Population genomic structure of the gelatinous zooplankton species Mnemiopsis leidyi in its nonindigenous range in the North Sea

Nonindigenous species pose a major threat for coastal and estuarine ecosystems. Risk management requires genetic information to establish appropriate management units and infer introduction and dispersal routes. We investigated one of the most successful marine invaders, the ctenophore Mnemiopsis leidyi, and used genotyping-by-sequencing (GBS) to explore the spatial population structure in its nonindigenous range in the North Sea. We analyzed 140 specimens collected in different environments, including coastal and estuarine areas, and ports along the coast. Single nucleotide polymorphisms (SNPs) were called in approximately 40 k GBS loci. Population structure based on the neutral SNP panel was significant (F-ST .02; p < .01), and a distinct genetic cluster was identified in a port along the Belgian coast (Ostend port; pairwise F-ST .02-.04; p < .01). Remarkably, no population structure was detected between geographically distant regions in the North Sea (the Southern part of the North Sea vs. the Kattegat/Skagerrak region), which indicates substantial gene flow at this geographical scale and recent population expansion of nonindigenous M. leidyi. Additionally, seven specimens collected at one location in the indigenous range (Chesapeake Bay, USA) were highly differentiated from the North Sea populations (pairwise F-ST .36-.39; p < .01). This study demonstrates the utility of GBS to investigate fine-scale population structure of gelatinous zooplankton species and shows high population connectivity among nonindigenous populations of this recently introduced species in the North Sea. OPEN RESEARCH BADGES This article has earned an Open Data Badge for making publicly available the digitally-shareable data necessary to reproduce the reported results. The data is available at: The DNA sequences generated for this study are deposited in the NCBI sequence read archive under SRA accession numbers -, and will be made publically available upon publication of this manuscript

The Heregulin/Human Epidermal Growth Factor Receptor as a New Growth Factor System in Melanoma with Multiple Ways of Deregulation

In a screening for new growth factors released by melanoma cells, we found that the p185-phosphorylating capacity of a medium conditioned by a melanoma cell line was due to the secretion of heregulin, a ligand for the human epidermal growth factor receptor (HER) family of receptor tyrosine kinases. Expression of heregulin, including a new isoform, and secretion of functionally active protein was found in several cell lines. Receptor activation by heregulin, either autocrine or paracrine, resulted in a potent growth stimulation of both melanocytes and melanoma cells. Heregulin receptor HER3 and coreceptor HER2 were the main receptors expressed by these cells. Nevertheless, none of the cell lines in our panel overexpressed HER2 or HER3. In contrast, loss of HER3 was found in two cell lines, whereas one cell line showed loss of functional HER2, both types of deregulations resulting in unresponsiveness to heregulin. This implies the heregulin/HER system as a possible important physiologic growth regulatory system in melanocytes in which multiple deregulations may occur during progression toward melanoma, all resulting in, or indicating, growth factor independence

Germline mutations in PMS2 and MLH1 in individuals with solitary loss of PMS2 expression in colorectal carcinomas from the Colon Cancer Family Registry Cohort

Immunohistochemistry for DNA mismatch repair proteins is used to screen for Lynch syndrome in individuals with colorectal carcinoma (CRC). Although solitary loss of PMS2 expression is indicative of carrying a germline mutation in PMS2, previous studies reported MLH1 mutation in some cases. We determined the prevalence of MLH1 germline mutations in a large cohort of individuals with a CRC demonstrating solitary loss of PMS2 expression

Single-walled carbon nanotube/polystyrene core-shell hybrids: synthesis and photoluminescence properties

International audienceThe formation of core-shell structures has permitted to improve greatly the emission properties of inorganic quantum dots. Single-Walled Carbon Nanotubes, thanks to their emission in the near infrared region, are promising materials for optoelectronics. However, the extreme sensitivity of nanotubes to their environment hinders their applications. Thus, the fabrication of tailor-made functional hybrid materials that preserve the optical properties of SWNTs and facilitate their manipulation is extremely important. Here, we describe the synthesis of core-shell nanotube materials made of SWNTs and polystyrene. We developed a two-step strategy that permits to form a stable and homogeneous layer of polymer around the nanotubes by adding first polystyrene via the micelle swelling method and then by locking the structure via radical polymerisation in micelles of styrene and divinylbenzene. After polymerisation and redispersion, the nanotube hybrids can be easily manipulated in solution; they still exhibited photoluminescence properties both in solution and in the solid state demonstrating that the SWNTs embedded in their polystyrene shell are isolated one from each other

Caractérisation et modélisation non linéaire de Transistors hyperfréquences à Effet de Champ à base de Nano tubes de Carbone (CNFETs) à l'aide d'un Analyseur de réseau Large Signal (LSNA)

National audienc

Characterization of carbon nanotube field-effect transistors using an active load pull LSNA setup

International audienceCNFETs have been characterized under large signal conditions at 600 MHz with an original active load pull setup using a LSNA. A non linear model of CNFET has been established and validated by comparison with the experimental results. Using this non linear model, design of circuits can be considered, allowing the optimization in non linear behavior

Caractérisation et modélisation non linéaire de transistors hyperfréquences à effet de champ à base de nanotubes de carbone (CNFETs) à l'aide d'un analyseur de réseau large signal (LSNA)

International audienc