Physical mapping and BAC-end sequence analysis provide initial insights into the flax (Linum usitatissimum L.) genome

<p>Abstract</p> <p>Background</p> <p>Flax (<it>Linum usitatissimum </it>L.) is an important source of oil rich in omega-3 fatty acids, which have proven health benefits and utility as an industrial raw material. Flax seeds also contain lignans which are associated with reducing the risk of certain types of cancer. Its bast fibres have broad industrial applications. However, genomic tools needed for molecular breeding were non existent. Hence a project, Total Utilization Flax GENomics (TUFGEN) was initiated. We report here the first genome-wide physical map of flax and the generation and analysis of BAC-end sequences (BES) from 43,776 clones, providing initial insights into the genome.</p> <p>Results</p> <p>The physical map consists of 416 contigs spanning ~368 Mb, assembled from 32,025 fingerprints, representing roughly 54.5% to 99.4% of the estimated haploid genome (370-675 Mb). The N50 size of the contigs was estimated to be ~1,494 kb. The longest contig was ~5,562 kb comprising 437 clones. There were 96 contigs containing more than 100 clones. Approximately 54.6 Mb representing 8-14.8% of the genome was obtained from 80,337 BES. Annotation revealed that a large part of the genome consists of ribosomal DNA (~13.8%), followed by known transposable elements at 6.1%. Furthermore, ~7.4% of sequence was identified to harbour novel repeat elements. Homology searches against flax-ESTs and NCBI-ESTs suggested that ~5.6% of the transcriptome is unique to flax. A total of 4064 putative genomic SSRs were identified and are being developed as novel markers for their use in molecular breeding.</p> <p>Conclusion</p> <p>The first genome-wide physical map of flax constructed with BAC clones provides a framework for accessing target loci with economic importance for marker development and positional cloning. Analysis of the BES has provided insights into the uniqueness of the flax genome. Compared to other plant genomes, the proportion of rDNA was found to be very high whereas the proportion of known transposable elements was low. The SSRs identified from BES will be valuable in saturating existing linkage maps and for anchoring physical and genetic maps. The physical map and paired-end reads from BAC clones will also serve as scaffolds to build and validate the whole genome shotgun assembly.</p

CNS Delivery Via Adsorptive Transcytosis

Adsorptive-mediated transcytosis (AMT) provides a means for brain delivery of medicines across the blood-brain barrier (BBB). The BBB is readily equipped for the AMT process: it provides both the potential for binding and uptake of cationic molecules to the luminal surface of endothelial cells, and then for exocytosis at the abluminal surface. The transcytotic pathways present at the BBB and its morphological and enzymatic properties provide the means for movement of the molecules through the endothelial cytoplasm. AMT-based drug delivery to the brain was performed using cationic proteins and cell-penetrating peptides (CPPs). Protein cationization using either synthetic or natural polyamines is discussed and some examples of diamine/polyamine modified proteins that cross BBB are described. Two main families of CPPs belonging to the Tat-derived peptides and Syn-B vectors have been extensively used in CPP vector-mediated strategies allowing delivery of a large variety of small molecules as well as proteins across cell membranes in vitro and the BBB in vivo. CPP strategy suffers from several limitations such as toxicity and immunogenicity—like the cationization strategy—as well as the instability of peptide vectors in biological media. The review concludes by stressing the need to improve the understanding of AMT mechanisms at BBB and the effectiveness of cationized proteins and CPP-vectorized proteins as neurotherapeutics

Abstracts from the 20th International Symposium on Signal Transduction at the Blood-Brain Barriers

https://deepblue.lib.umich.edu/bitstream/2027.42/138963/1/12987_2017_Article_71.pd

Radiolysis of water in the vicinity of passive surfaces

International audiencePorous metals were used to describe the water radiolysis in the vicinity of metal surfaces. The hydroxyl radical production under gamma irradiation was measured by benzoate scavenging in water confined in a 200nm porous Ni base alloy or in Stainless steel. The presence of the metallic surfaces changed drastically the HO° production level and lifetime. The solvated electron production was measured via glycylglycine scavenging for Stainless steel and was found to be significantly smaller than hydroxyl production. These observations imply that interfacial radiolysis may deeply impact the corrosion behavior of the SS and Ni based alloys

Radiolysis influence on low alloy steel atmospheric corrosion at 80°C

International audienceThe degradation of iron-based materials by atmospheric corrosion is a well-known problem thatmay have incidence, especially for the storage of radioactive nuclear wastes. It is of importanceto evaluate the damages due to this kind of corrosion within long time-periods. One parameterwhich can influence atmospheric corrosion in the case of storage container is irradiation. Asatmospheric corrosion happens when a water film condensates at the surface of a material,radiolysis of this water film in contact with air can have for consequence the formation of acid anoxidizing species which can modify the corrosion process.As a consequence the aim of this work is to evaluate the influence of γ-irradiation onatmospheric corrosion of low alloy steel. In this goal, an experiment, called CASIMIR, has beendeveloped. During this experiment, samples of low alloy steel have been introduced into smallstainless steel container. In these ones, two different media has been introduced. The firstmedium is a small quantity of water in order to fix a relative humidity (RH) of 100 %. Thesecond medium is a melt of KH$_2$PO$_4$/ K$_2$HPO$_4$in a small quantity of water corresponding to arelative humidity of about 70% at the surface of the samples. The small containers have beenintroduced in a heating system which enables to fix a temperature of 80°C. This system has beeninstalled in an irradiation pool with three $^{60}$Co sources which fix, according to the location of thestainless steel in the system, a dose rate of 80 Gy.h$^{-1}$ or 20 Gy.h$^{-1}$ at the surface of the low alloysteel samples.After six, nine and twelve months of corrosion in these conditions some samples were extractedof the experiment and analyzed by different methods. Gravimetry after desquamation of thecorrosion layer enables to measure total corroded thickness in function of RH, dose rate andtime. As show on figure 1, after 6 month of exposure, sample aged with a RH of 100% are morecorroded than the one aged at 70%. Moreover the dose rate does not have an effect on thecorroded thickness for 20 Gy.h$^{-1}$ whereas it increases corrosion when the dose rate is equal to 80Gy.h$^{-1}$. This result is confirmed for longer times. Gas analysis after corrosion experiment haveshown that for the higher corrosion rate, oxygen was totally consumed after 6 month and revealalso a production of hydrogen. Microscopical observations also confirm the influence of doserate on atmospheric corrosion.All the results show that dose rate does not influence atmospheric corrosion until a valuebetween 20 and 80 Gy.h$^{-1}$. For a dose rate up to these thresholds, irradiation increase corrosionrate on low alloy steel in presence of high values of relative humilities.6th International Works

On corrosion of carbon steels in Callovo-Oxfordian clay: complementary EIS, gravimetric and structural study providing insights on long term behaviour in French geological disposal conditions

International audienc

«Nano-réacteurs à base de cyclodextrines amphiphiles pour la catalyse et la vectorisation»

National audienc

«Nano-réacteurs à base de cyclodextrines amphiphiles pour la catalyse et la vectorisation»

National audienc

Optical and MRI multifunctional nanoprobe for targeting gliomas

A multifunctional nanoprobe capable of targeting glioma cells, detectable by both magnetic resonance imaging and fluorescence microscopy, was developed. The nanoprobe was synthesized by coating iron oxide nanoparticles with covalently bound bifunctional poly(ethylene glycol) (PEG) polymer, which were subsequently functionalized with chlorotoxin and the near-infrared fluorescing molecule Cy5.5. Both MR imaging and fluorescence microscopy showed significant preferential uptake of the nanoparticle conjugates by glioma cells. Such a nanoprobe could potentially be used to image resections of glioma brain tumors in real time and to correlate preoperative diagnostic images with intraoperative pathology at cellular-level resolution