Massive presence of insertion sequences in the genome of SOPE, the primary endosymbiont of the rice weevil Sitophilus oryzae

Bacteria that establish an obligate intracellular relationship with eukaryotic hosts undergo an evolutionary genomic reductive process. Recent studies have shown an increase in the number of mobile elements in the first stage of the adaptive process towards intracellular life, although these elements are absent in ancient endosymbionts. Here, the genome of SOPE, the obligate mutualistic endosymbiont of rice weevils, was used as a model to analyze the initial events that occur after symbiotic integration. During the first phases of the SOPE genome project, four different types of insertion sequence (IS) elements, belonging to well-characterized IS families from γ-proteobacteria, were identified. In the present study, these elements, which may represent more than 20% of the complete genome, were completely characterized; their relevance as a source of gene inactivation, chromosomal rearrangements, and as participants in the genome reductive process are discussed herein. [Int Microbiol 2008; 11(1): 41-48

Massive presence of insertion sequences in the genome of SOPE, the primary endosymbiont of the rice weevil Sitophilus oryzae

Bacteria that establish an obligate intracellular relationship with eukaryotic hosts undergo an evolutionary genomic reductive process. Recent studies have shown an increase in the number of mobile elements in the first stage of the adaptive process towards intracellular life, although these elements are absent in ancient endosymbionts. Here, the genome of SOPE, the obligate mutualistic endosymbiont of rice weevils, was used as a model to analyze the initial events that occur after symbiotic integration. During the first phases of the SOPE genome project, four different types of insertion sequence (IS) elements, belonging to well-characterized IS families from γ-proteobacteria, were identified. In the present study, these elements, which may represent more than 20% of the complete genome, were completely characterized; their relevance as a source of gene inactivation, chromosomal rearrangements, and as participants in the genome reductive process are discussed herein.Gil Garcia, Rosario, [email protected] ; Belda Cuesta, Eugenio, [email protected] ; Gosalbes Soler, Maria Jose, [email protected] ; Delaye, Luis, [email protected] ; Silva Moreno, Francisco J., [email protected] ; Moya Simarro, Andres, [email protected] ; Latorre Castillo, Amparo, [email protected]

Avoiding Progenitor Bias: The Structural and Mass Evolution of Brightest Group and Cluster Galaxies in Hierarchical Models since z≾1

The mass and structural evolution of massive galaxies is one of the hottest topics in galaxy formation. This is because it may reveal invaluable insights into the still debated evolutionary processes governing the growth and assembly of spheroids. However, direct comparison between models and observations is usually prevented by the so-called progenitor bias, i.e., new galaxies entering the observational selection at later epochs, thus eluding a precise study of how pre-existing galaxies actually evolve in size. To limit this effect, we here gather data on high-redshift brightest group and cluster galaxies, evolve their (mean) host halo masses down to z = 0 along their main progenitors, and assign as their "descendants" local Sloan Digital Sky Survey central galaxies matched in host halo mass. At face value, the comparison between high redshift and local data suggests a noticeable increase in stellar mass of a factor of ≳ 2 since z ~ 1, and of ≳ 2.5 in mean effective radius. We then compare the inferred stellar mass and size growth with those predicted by hierarchical models for central galaxies, selected at high redshifts to closely match the halo and stellar mass bins as in the data. Only hierarchical models characterized by very limited satellite stellar stripping and parabolic orbits are capable of broadly reproducing the stellar mass and size increase of a factor of ~2-4 observed in cluster galaxies since z ~ 1. The predicted, average (major) merger rate since z ~ 1 is in good agreement with the latest observational estimates

Properties of Electrodeposited CuSCN 2D Layers and Nanowires Influenced by Their Mixed Domain Structure

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ETUDE ET REALISATION D'UN TELEMETRE LASER PAR TEMPS DE VOL

GRENOBLE1-BU Sciences (384212103) / SudocSudocFranceF

Impact and behavior of Sn during the Ni/GeSn solid-state reaction

International audienceNi-based intermetallics are promising materials for forming efficient contacts in GeSn-based Si photonic devices. However, the role that Sn might have during the Ni/GeSn solid-state reaction (SSR) is not fully understood. A comprehensive analysis focused on Sn segregation during the Ni/GeSn SSR was carried out. In situ X-ray diffraction and cross-section transmission electron microscopy measurements coupled with energy-dispersive X-ray spectrometry and electron energy-loss spectroscopy atomic mappings were performed to follow the phase sequence, Sn distribution and segregation. The results showed that, during the SSR, Sn was incorporated into the intermetallic phases. Sn segregation happened first around the grain boundaries (GBs) and then towards the surface. Sn accumulation around GBs hampered atom diffusion, delaying the growth of the Ni(GeSn) phase. Higher thermal budgets will thus be mandatory for formation of contacts in high-Sn-content photonic devices, which could be detrimental for thermal stability

Atomic Scale Investigation of Arsenic Segregation in High-k Metal Gate Stacks

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Behavior of B in passivating gels formed on International Simple Glass in acid and basic pH

International audienceInternational Simple Glass altered for years in silica saturated conditions develops a passivating gel, which retains some B and Ca in its the inner region. These elements could impact the way the gel limits glass alteration. However, the retention mechanism, speciation, and diffusion properties of these elements are still unknown. First, we found that the presence of B and Ca in solution can dramatically slow down glass alteration. However, splitting the B and Ca into two different solutions with other glass elements did not give similar protection against glass alteration. Further experiments in basic and acid pHs revealed that i) water diffusion is not dramatically affected by the retention of B and Ca in passivating gels, and ii) slow diffusion and high retention of B is observed only in gels formed in basic pH. This mechanism could explain how passivating gels control the residual rate

GeSn heterostructure micro-disk laser operating at 230 K

International audienceWe demonstrate lasing up to 230 K in a GeSn heterostructure micro-disk cavity. The GeSn 16.0% optically active layer was grown on a step-graded GeSn buffer, limiting the density of misfit dislocations. The lasing wavelengths shifted from 2720 to 2890 nm at 15 K up to 3200 nm at 230 K. Compared to results reported elsewhere, we attribute the increase in maximal lasing temperature to two factors: a stronger optical confinement by a thicker active layer and a better carrier confinement provided by a GeSn 13.8% / GeSn 16.0% / GeSn 13.8% double heterostructure