Search results for " Structure"
showing 10 items of 25475 documents
Genetic Analysis of Human Preimplantation Embryos
2016
Preimplantation development comprises the initial stages of mammalian development, before the embryo implants into the mother's uterus. In normal conditions, after fertilization the embryo grows until reaching blastocyst stage. The blastocyst grows as the cells divide and the cavity expands, until it arrives at the uterus, where it "hatches" from the zona pellucida to implant into the uterine wall. Nevertheless, embryo quality and viability can be affected by chromosomal abnormalities, most of which occur during gametogenesis and early embryo development; human embryos produced in vitro are especially vulnerable. Therefore, the selection of chromosomally normal embryos for transfer in assis…
T-Box Genes in Drosophila Limb Development
2017
T-box genes are essential for limb development in vertebrates and arthropods. The Drosophila genome encodes eight T-box genes, six of which are expressed in limb ontogenesis. The Tbx20-related gene pair midline and H15 is essential for dorso-ventral patterning of the Drosophila legs. The three Tbx6-related Dorsocross genes are required for epithelial remodeling during wing development. The Drosophila gene optomotor-blind (omb) is the only member of the Tbx2 subfamily in the fly and is predominantly involved in wing development. Omb is essential for wing development and is sufficient to promote the development of a second wing pair. Targeted manipulations of omb expression have shown that th…
Lost Strings in Genomes: What Sense Do They Make?
2017
We studied the sets of avoided strings to be observed over a family of genomes. It was found that the length of the minimal avoided string rarely exceeds 9 nucleotides, with neither respect to a phylogeny of a genome under consideration. The lists of the avoided strings observed over the sets of (related) genomes have been analyzed. Very low correlation between the phylogeny, and the set of those strings has been found.
High prevalence and moderate diversity of Pseudomonas aeruginosa in the U-bends of high-risk units in hospital
2017
The presence of P. aeruginosa in water supply is clearly identified as a risk factor for P. aeruginosa infection in critical care units, even if routes of transmission are often unclear and remain a matter of debate. We determined here the frequency of U-bends contaminated with P. aeruginosa in high-risk units and described the population structure of this opportunistic pathogen in a non-outbreak situation. Eighty-seven U-bends from sinks of rooms in five wards were sampled 3 times and P. aeruginosa was detected in 121 of the 261 (46.4%) U-bend samples. We genotyped 123 P. aeruginosa isolates with pulsed-field gel electrophoresis and multilocus sequence typing and found 41 pulsotypes distri…
Long-term dynamics in microbial eukaryotes communities: a palaeolimnological view based on sedimentary DNA
2016
International audience; Assessing the extent to which changes in lacustrine biodiversity are affected by anthropogenic or climatic forces requires extensive palaeolimnological data. We used high-throughput sequencing to generate time-series data encompassing over 2200 years of microbial eukaryotes (protists and Fungi) diversity changes from the sedimentary DNA record of two lakes (Lake Bourget in French Alps and Lake Igaliku in Greenland). From 176 samples, we sequenced a large diversity of microbial eukaryotes, with a total 16 386 operational taxonomic units distributed within 50 phylogenetic groups. Thus, microbial groups, such as Chlorophyta, Dinophyceae, Haptophyceae and Ciliophora, tha…
Population Structure in the Model Grass Brachypodium distachyon Is Highly Correlated with Flowering Differences across Broad Geographic Areas
2016
The small, annual grass Brachypodium distachyon (L.) Beauv., a close relative of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), is a powerful model system for cereals and bioenergy grasses. Genome-wide association studies (GWAS) of natural variation can elucidate the genetic basis of complex traits but have been so far limited in B. distachyon by the lack of large numbers of well-characterized and sufficiently diverse accessions. Here, we report on genotyping-by-sequencing (GBS) of 84 B. distachyon, seven B. hybridum, and three B. stacei accessions with diverse geographic origins including Albania, Armenia, Georgia, Italy, Spain, and Turkey. Over 90,000 high-quality single-nu…
BDE-47 exposure modulates cellular responses, oxidative stress and biotransformation related-genes in Mytilus galloprovincialis.
2020
Abstract Polybrominated diphenyl ethers (PBDEs) are flame retardants, characterized by elevated stability in the marine environment, where are accumulated by organisms, inducing a wide panel of negative effects. In this study, some biochemical patterns related to toxicity, biotransformation and oxidative stress, were studied in the marine model system, Mytilus galloprovincialis, exposed to BDE-47. Mussels were fed with microalgae, previously treated with increasing concentrations of PBDEs (maximum dose 100 ng L-1 of BDE-47 per day). After 15 days of treatment, mussels were fed with the same diet without BDE-47, for additional 15 days. Gills and digestive glands were analyzed at T 0, at 15 a…
Alternative yeasts for winemaking: Saccharomyces non-cerevisiae and its hybrids
2017
Wine fermentation has not significantly changed since ancient times and the most traditional aspects are seen by the market as elements that uplift wine nuances and quality. In recent years, new trends have emerged from the sector in line with consumer preferences, and due to the effects of global climate change on grape ripening. In the first cases, the consumers are looking for wines with less ethanol and fruitier aromas and in the second cases the wineries want to reduce the wine alcohol levels and/or astringency. New yeast starters of alternative Saccharomyces species and their hybrids can help to solve some problems that wineries face. In this article we review several physiological an…
Structural commonalities and deviations in the hierarchical organization of crossed-lamellar shells: A case study on the shell of the bivalve Glycyme…
2016
11 pages; International audience; The structural organization of the palliostracum—the dominant part of the shell which is formed by the mantle cells—of Glycymeris glycymeris (Linné 1758) is comprised of five hierarchical levels with pronounced structural commonalities and deviations from other crossed-lamellar shells. The hierarchical level known as second order lamellae, present within other crossed-lamellar shells, is absent highlighting a short-coming of the currently used nomenclature. On the mesoscale, secondary microtubules penetrate the palliostracum and serve as crack arrestors. Moreover, the growth lamellae follow bent trajectories possibly impacting crack propagation, crack defle…
Genetic characterization of influenza viruses from influenza-related hospital admissions in the St. Petersburg and Valencia sites of the Global Influ…
2016
Abstract Background Continuous surveillance for genetic changes in circulating influenza viruses is needed to guide influenza prevention and control. Objectives To compare intra-seasonal influenza genetic diversity of hemagglutinin in influenza A strains isolated from influenza hospital admissions collected at two distinct sites during the same season. Study design Comparative phylogenetic analysis of full-length hemagglutinin genes from 77 isolated influenza A viruses from the St. Petersburg, Russian Federation and Valencia, Spain sites of the Global Influenza Hospital Surveillance Network (GIHSN) during the 2013/14 season. Results We found significant variability in A(H3N2) and A(H1N1)pdm…