In silico analyses of mitochondrial ORFans in freshwater mussels (Bivalvia: Unionoida) provide a framework for future studies of their origin and function

Protein sequence alignment of Cumberlandia monodonta M-ORF and ATP8, along with ATP8 from the most diverse members of the Mt_ATP-synt_B superfamily (pfam02326). Homo sapiens ATP8 has also been included for comparison. The alignment was generated using T-COFFEE. The most conserved N-terminal domain, i.e. the best aligned portion, is in red; the rest of the sequences are rather badly aligned (in green). Consensus is shown and indicates good (red), intermediate (yellow), and bad alignment (green), and insertion/deletion (in blue). Cumberland, Cumberlandia monodonta; H_sapiens, Homo sapiens; Malawimonas, Malawimonas sp. (Excavate); Thraustoch, Thraustochytrium sp. (Stramenopiles); Mesostigma, Mesostigma sp. (Streptophyta); Reclinomon, Reclinomonas sp. (Protozoa); Porphyra, Porphyra sp. (Rhodophyta); Cyanidiosc, Cyanidioschyzon sp. (Rhodophyta); Pseudendoc, Pseudendoclonium sp. (Chlorophyta); Acanthamoe, Acanthamoeba sp. (Amoebozoa); Nephroselm, Nephroselmis sp. (Streptophyta). (PDF 236 kb

Synthesis of globopentaose using a novel β1,3-galactosyltransferase activity of the Haemophilus influenzae β1,3-N-acetylgalactosaminyltransferase LgtD

AbstractWe have previously described a bacterial system for the conversion of globotriaose (Gb3) into globotetraose (Gb4) by a metabolically engineered Escherichia coli strain expressing the Haemophilus influenzae lgtD gene encoding β1,3-N-acetylgalactosaminyltransferase [Antoine, T., Bosso, C., Heyraud, A. Samain, E. (2005) Large scale in vivo synthesis of globotriose and globotetraose by high cell density culture of metabolically engineered Escherichia coli. Biochimie 87, 197–203]. Here, we found that LgtD has an additional β1,3-galactosyltransferase activity which allows our bacterial system to be extended to the synthesis of the carbohydrate portion of globopentaosylceramide (Galβ-3GalNAcβ-3Galα-4Galβ-4Glc) which reacts with the monoclonal antibody defining the stage-specific embryonic antigen-3. In vitro assays confirmed that LgtD had both β1,3-GalT and β1,3-GalNAcT activities and showed that differences in the affinity for Gb3 and Gb4 explain the specific and exclusive formation of globopentaose

Large area Bragg grating for pump recycling in cladding-pumped multicore erbium-doped fiber amplifiers

We demonstrate for the first time that a Bragg grating can be written over a large area inside the cladding of a multicore erbium-doped fiber amplifier to increase the power conversion efficiency (PCE) by recycling the output pump power. Our results indicate that a Bragg grating covering ~25% of the cladding area allows to recycle 19% of the output pump power which leads to a relative increase of the PCE by 16% for an input pump power of 10.6 W in the specific case of an eight-core erbium-doped fiber with a length of 20.3 m and one core loaded with an input signal power of 1.5 dBm

Evolution of sex-dependent mtDNA transmission in freshwater mussels (Bivalvia: Unionida)

Doubly uniparental inheritance (DUI) describes a mode of mtDNA transmission widespread in gonochoric freshwater mussels (Bivalvia: Palaeoheterodonta: Unionida). In this system, both female- and male-transmitted mtDNAs, named F and M respectively, coexist in the same species. In unionids, DUI is strictly correlated to gonochorism and to the presence of the atypical open reading frames (ORFans) F-orf and M-orf, respectively inside F and M mtDNAs, which are hypothesized to participate in sex determination. However, DUI is not found in all three Unionida superfamilies (confirmed in Hyrioidea and Unionoidea but not in Etherioidea), raising the question of its origin in these bivalves. To reconstruct the co-evolution of DUI and of ORFans, we sequenced the mtDNAs of four unionids (two gonochoric with DUI, one gonochoric and one hermaphroditic without DUI) and of the related gonochoric species Neotrigonia margaritacea (Palaeoheterodonta: Trigoniida). Our analyses suggest that rearranged mtDNAs appeared early during unionid radiation, and that a duplicated and diverged atp8 gene evolved into the M-orf associated with the paternal transmission route in Hyrioidea and Unionoidea, but not in Etherioidea. We propose that novel mtDNA-encoded genes can deeply influence bivalve sex determining systems and the evolution of the mitogenomes in which they occur

La conscience morphologique est-elle une variable importante dans l’apprentissage de la lecture?

Le présent article est une revue synthétique des travaux portant sur lesliens entre conscience morphologique et apprentissage de la lecture. Cettesynthèse permet de confirmer que la conscience morphologique contribuebien à l’apprentissage de la lecture (tant au niveau de l’installation deshabiletés de décodage qu’au niveau du développement de la compréhension).Toutefois, il semble que ce ne sont pas tout à fait les mêmes aspects de la conscience morphologique qui sont liés aux capacités de décodage et aux capacités de compréhension. Des recherches doivent donc être développées pour mieux appréhender les rôles respectifs de chacune des composantes de la conscience morphologique

Optimization criteria and design of few-mode erbium-doped fibers for cladding-pumped amplifiers

We propose a novel optimization method that combines two design criteria to reduce the differential modal gain (DMG) in few-mode cladding-pumped erbium-doped fiber amplifiers (FM-EDFAs). In addition to the standard criterion that considers the mode intensity and dopant profile overlap, we introduce a second criterion that ensures that all doped regions have the same saturation behavior. With these two criteria, we define a figure-of-merit (FOM) that allows the design of MM-EDFAs with low DMG without high computational cost. We illustrate this method with the design of six-mode erbium-doped fibers (EDFs) for amplification over the C-Band targeting designs that are compatible with standard fabrication processes. The fibers have either a step-index or a staircase refractive index profile (RIP), with two ring-shaped erbium-doped regions in the core. With a staircase RIP, a fiber length of 29 m and 20 W of pump power injected in the cladding, our best design leads to a minimum gain of 22.6 dB while maintaining a DMGmax under 0.18 dB. We further show that the FOM optimization achieves a robust design with low DMG over a wide range of variations in signal power, pump power and fiber length

La conscience morphologique est-elle une variable importante dans l’apprentissage de la lecture?

Le présent article est une revue synthétique des travaux portant sur lesliens entre conscience morphologique et apprentissage de la lecture. Cettesynthèse permet de confirmer que la conscience morphologique contribuebien à l’apprentissage de la lecture (tant au niveau de l’installation deshabiletés de décodage qu’au niveau du développement de la compréhension).Toutefois, il semble que ce ne sont pas tout à fait les mêmes aspects de la conscience morphologique qui sont liés aux capacités de décodage et aux capacités de compréhension. Des recherches doivent donc être développées pour mieux appréhender les rôles respectifs de chacune des composantes de la conscience morphologique

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

Analysis of inter-core cross-gain modulation in cladding pumped multi-core fiber amplifiers

We numerically investigate pump-induced gain variations in eight-core fi ber amplifi ers. We compare two fi bers with different erbium profi les by varying input power from -25 dBm to 0 dBm in one or four cores. Inter-core cross-gain modulation is < 0.6 dB

Modeling and characterization of cladding-pumped erbium-ytterbium co-doped fibers for amplification in communication systems

Cladding-pumped optical fiber amplifiers are of increased interest in the context of space-division multiplexing but are known to suffer from low power efficiency. In this context, ytterbium (Yb) co-doping can be an attractive solution to improve the performance of erbium (Er) doped fiber amplifiers. We present a detailed direct comparison between Er/Yb-co-doping and Er-doping using numerical simulations validated by experimental results. Two double-cladding fibers, one doped with Er only and the other one co-doped with Er and Yb, were designed, fabricated and characterized. Using the experimentally extracted parameters, we simulate multi-core fiber amplifiers and investigate the interest of Er/Yb-co-doping. We calculate the minimum gain of the amplifiers over a 35-nm spectral window considering various scenarios