Genetic characterization of Acipenser sturio L., 1758 in relation to other sturgeon species using satellite DNA

We obtained and characterized a satellite (st) DNA family named HindIII from the genomes of the Adriatic sturgeon Acipenser naccarii Bonaparte, 1836, Siberian sturgeon Acipenser baerii Brandt, 1869, and beluga sturgeon Huso huso (L., 1758). We did not find this stDNA in the genome of the Atlantic sturgeon Acipenser sturio L., 1758. The comparison of sturgeon species using the HindIII stDNA revealed the following: (1) A. naccarii and A. baerii are closely related; (2) H. huso appears to belong to the genus Acipenser and, probably, Huso is not a separate genus within the Acipenserinae; (3) A. sturio differs from the other three studied species by the absence of the HindIII stDNA and, most likely, it represents a separate evolutionary lineage within the Acipenseridae. The data on the HindIII stDNA can be successfully used for species identification of sturgeon specimens captured in different European regions.En este trabajo presentamos la caracterización del genoma de Acipenser sturio L., 1758 en relación con el genoma de Acipenser naccarii Bonaparte, 1836, Acipenser baerii Brandt, 1869 y Huso huso (L., 1758) utilizando una familia de ADN satélite (la familia HindIII). Nuestro análisis revela que: (1) A. naccarii y A. baerii son especies muy emparentadas; (2) H. huso aparece muy relacionada con las especies del género Acipenser y, probablemente, podría ser considerada como una especie perteneciente a dicho género, y (3) A. sturio difiere del resto de las especies analizadas, lo que sugiere que esta especie ha debido seguir una evolución independiente respecto a las otras especies. Estos datos pueden ser muy útiles, no sólo para establecer las relaciones filogenéticas entre A. sturio y las otras especies de Acipenseridae, sino también para la identificación de ejemplares de esturiones capturados en diferentes regiones europeas.Instituto Español de Oceanografí

Three-body structure of low-lying 18Ne states

We investigate to what extent 18Ne can be descibed as a three-body system made of an inert 16O-core and two protons. We compare to experimental data and occasionally to shell model results. We obtain three-body wave functions with the hyperspherical adiabatic expansion method. We study the spectrum of 18Ne, the structure of the different states and the predominant transition strengths. Two 0+, two 2+, and one 4+ bound states are found where they are all known experimentally. Also one 3+ close to threshold is found and several negative parity states, 1-, 3-, 0-, 2-, most of them bound with respect to the 16O excited 3- state. The structures are extracted as partial wave components, as spatial sizes of matter and charge, and as probability distributions. Electromagnetic decay rates are calculated for these states. The dominating decay mode for the bound states is E2 and occasionally also M1.Comment: 17 pages, 5 figures (version to appear in EPJA

Expanding the Search for Sperm Transmission Elements in the Mitochondrial Genomes of Bivalve Mollusks

This research was funded by Discovery grants from the Natural Sciences and Engineering Research Council of Canada (NSERC) to D.T.S. (grant number 217175) and S.B. (grant number 435656). E.E.C. was funded by the European Union's Horizon 2020 research and innovation programme under the Marie Skodowska-Curie grant agreement No713750, carried out with the financial support of the Regional Council of Provence- Alpes-Cote d'Azur and with the financial support of the A*MIDEX (n degrees ANR- 11-IDEX-0001-02), funded by the Investissements d'Avenir project funded by the French Government, managed by the French National Research Agency [ANR]. B.M.R. was supported by an NSERC CGS-D award, Killam Predoctoral Scholarship, and a NS Graduate Scholarship. M.A.G.-R. was supported by a Harrison McCain Visiting Professorship Award at Acadia University from the Harrison McCain Foundation.Doubly uniparental inheritance (DUI) of mitochondrial DNA (mtDNA) in bivalve mollusks is one of the most notable departures from the paradigm of strict maternal inheritance of mtDNA among metazoans. Recently, work on the Mediterranean mussel Mytilus galloprovincialis suggested that a nucleotide motif in the control region of this species, known as the sperm transmission element (STE), helps protect male-transmitted mitochondria from destruction during spermatogenesis. Subsequent studies found similar, yet divergent, STE motifs in other marine mussels. Here, we extend the in silico search for mtDNA signatures resembling known STEs. This search is carried out for the large unassigned regions of 157 complete mitochondrial genomes from within the Mytiloida, Veneroida, Unionoida, and Ostreoida bivalve orders. Based on a sliding window approach, we present evidence that there are additional putative STE signatures in the large unassigned regions of several marine clams and freshwater mussels with DUI. We discuss the implications of this finding for interpreting the origin of doubly uniparental inheritance in ancestral bivalve mollusks, as well as potential future in vitro and in silico studies that could further refine our understanding of the early evolution of this unusual system of mtDNA inheritance.Natural Sciences and Engineering Research Council of Canada (NSERC) 217175 435656European Commission 713750Region Provence-Alpes-Cote d'AzurFrench National Research Agency (ANR) ANR- 11-IDEX-0001-02 NSERC CGS-D awardKillam Predoctoral ScholarshipNS Graduate ScholarshipHarrison McCain Visiting Professorship Award at Acadia University from the Harrison McCain Foundatio

High spatial resolution optical imaging of the multiple T Tauri system LkH{\alpha} 262/LkH{\alpha} 263

We report high spatial resolution i' band imaging of the multiple T Tauri system LkH$\alpha$ 262/LkH$\alpha$ 263 obtained during the first commissioning period of the Adaptive Optics Lucky Imager (AOLI) at the 4.2 m William Herschel Telescope, using its Lucky Imaging mode. AOLI images have provided photometry for each of the two components LkH$\alpha$ 263 A and B (0.41 arcsec separation) and marginal evidence for an unresolved binary or a disc in LkH$\alpha$ 262. The AOLI data combined with previously available and newly obtained optical and infrared imaging show that the three components of LkH$\alpha$ 263 are co-moving, that there is orbital motion in the AB pair, and, remarkably, that LkH$\alpha$ 262-263 is a common proper motion system with less than 1 mas/yr relative motion. We argue that this is a likely five-component gravitationally bounded system. According to BT-settl models the mass of each of the five components is close to 0.4 M$_{\odot}$ and the age is in the range 1-2 Myr. The presence of discs in some of the components offers an interesting opportunity to investigate the formation and evolution of discs in the early stages of multiple very low-mass systems. In particular, we provide tentative evidence that the disc in 263C could be coplanar with the orbit of 263AB.Comment: 11 pages, 7 figures, Accepted 2016 May