Polymérisation radicalaire contrôlée par les nitroxydes en émulsion sans tensioactif pour le développement industriel de latex à morphologies variées

Water-soluble, SG1-based macroalkoxyamines composed of methacrylic acid with a low percentage of sodium 4-styrene sulfonate were synthesized in aqueous solution. These macroalkoxyamines were used as macroinitiators in the surfactant-free emulsion polymerization ofmethyl methacrylate or n-butyl methacrylate with a low percentage of styrene. The polymerization induced self-assembly of the so-formed amphiphilic block copolymers leads to nanoobjects with various morphologies (spheres, fibers, vesicles), depending on their hydrophilic/hydrophobic balance. The most interesting morphology is the nanofiber type of organization as the suspensions presentshear-thinning properties at low concentration and viscoelastic behavior at high concentration. The synthesis of these latexes was investigated and developed in one-pot conditions in order to allow further production at the industrial scale.La synthèse de macroalcoxyamines hydrosolubles à partir d’acide méthacrylique et d’un faible pourcentage de styrène sulfonate de sodium a été étudiée en solution aqueuse. Ces macroalcoxyamines ont été utilisées comme macroamorceurs pour la polymérisation en émulsion sanstensioactif du méthacrylate de méthyle et du méthacrylate de n-butyle avec un faible pourcentage destyrène. Les copolymères diblocs amphiphiles produits s’auto-assemblent in situ et conduisent, en fonction de leur taux d’hydrophilie, à l’obtention de nano-objets présentant des morphologies variées(sphères, fibres, vésicules). La plus intéressante est la morphologie fibrillaire car les suspensions correspondantes présentent des propriétés rhéofluidifiantes à basse concentration et possèdent un comportement viscoélastique à haute concentration. La synthèse de ces latex a été étudiée et développée dans des conditions monotopes les plus proches possibles d’une production industrielle

Polymerization-Induced Self-Assembly of Block Copolymer Nano-objects via RAFT Aqueous Dispersion Polymerization

In this Perspective, we discuss the recent development of polymerization-induced self-assembly mediated by reversible addition–fragmentation chain transfer (RAFT) aqueous dispersion polymerization. This approach has quickly become a powerful and versatile technique for the synthesis of a wide range of bespoke organic diblock copolymer nano-objects of controllable size, morphology, and surface functionality. Given its potential scalability, such environmentally-friendly formulations are expected to offer many potential applications, such as novel Pickering emulsifiers, efficient microencapsulation vehicles, and sterilizable thermo-responsive hydrogels for the cost-effective long-term storage of mammalian cells

A Vesicle-to-Worm Transition Provides a New High-Temperature Oil Thickening Mechanism

Diblock copolymer vesicles are prepared via RAFT dispersion polymerization directly in mineral oil. Such vesicles undergo a vesicle‐to‐worm transition on heating to 150 °C, as judged by TEM and SAXS. Variable‐temperature 1H NMR spectroscopy indicates that this transition is the result of surface plasticization of the membrane‐forming block by hot solvent, effectively increasing the volume fraction of the stabilizer block and so reducing the packing parameter for the copolymer chains. The rheological behavior of a 10 % w/w copolymer dispersion in mineral oil is strongly temperature‐dependent: the storage modulus increases by five orders of magnitude on heating above the critical gelation temperature of 135 °C, as the non‐interacting vesicles are converted into weakly interacting worms. SAXS studies indicate that, on average, three worms are formed per vesicle. Such vesicle‐to‐worm transitions offer an interesting new mechanism for the high‐temperature thickening of oils

Effect of the probiotic Lactobacillus rhamnosus on the expression of genes involved in European eel spermatogenesis

[EN] Positive effects of probiotics on fish reproduction have been reported in several species. In the present study, 40 male European eels were weekly treated with recombinant hCG for 9 weeks and with three different concentrations (10(3), 10(5), and 10(6) CFU/mL) of probiotic Lactobacillus rhamnosus IMC 501 (Sinbyotec, Italy). The probiotics were daily added to the water from the sixth week of the hCG treatment. Males from the treated and control groups were sacrificed after 1, 2, and 3 weeks of probiotic treatment (seventh ninth weeks of hCG treatment); at this point, sperm and testis samples were also collected. Sperm volume was estimated, and motility was analyzed by computer-assisted sperm analysis software. Alternations in transcription of specific genes involved in reproductive process such as activin, androgen receptors alpha and beta (ar alpha and ar beta), progesterone receptor 1 (pr1), bone morphogenetic protein 15 (bmp15), and FSH receptor (fshr) were analyzed in the testis. After 2 weeks of probiotic treatment, sperm production and sperm motility parameters (percentage of motile cells and percentage of straight-swimming spermatozoa) were increased in the European eel treated with 105 CFU/mL compared to controls or to the other probiotic doses. These changes were associated with increases in messenger RNA expression of activin, ar alpha, ar beta, pr1, and fshr. Conversely, after 3 weeks, activin and pr1 expression decreased. No significant changes were observed on bmp15 expression throughout the duration of the treatment with 10(5) CFU/mL dose. The lowest and highest probiotic dose (10(3) and 10(6) CFU/mL, respectively) inhibited the transcription of all genes along all the experiment, except for ar alpha and ar beta after 1 week of probiotic treatment when compared to controls. The changes observed by transcriptomic analysis and the sperm parameters suggest that a treatment with L rhamnosus at 10(5) CFU/mL for 2 weeks could improve spermatogenesis process in Anguilla anguilla. (C) 2015 Elsevier Inc. All rights reserved.This study was funded by the European Community’s 7th FP (grant agreement no. 245257, PRO-EEL) and COST Office (Food and Agriculture COST Action FA1205: AQUAGAMETE) Victor Gallego and M. Carmen Vilchez have predoctoral grants from MINISTERIO DE ECONOMIA Y COMPETITIVIDAD (BES-2009-020310) and UNIVERSIDAD POLITECNICA DE VALENCIA PAID Program (2011-S2-02-6521), respectively. Fondo Ateneo 2012 to Oliana Carnevali.Vilchez Olivencia, MC.; Santangeli, S.; Maradonna, F.; Gioacchini, G.; Verdenelli, C.; Gallego Albiach, V.; Peñaranda, D.... (2015). Effect of the probiotic Lactobacillus rhamnosus on the expression of genes involved in European eel spermatogenesis. Theriogenology. 84(8):1321-1331. https://doi.org/10.1016/j.theriogenology.2015.07.011S1321133184

Sexual dimorphism of drumming muscles in European hake (Merluccius merluccius)

Dissections of mature and non-mature European hake males and females (N = 142) collected in waters off the western coast of Norway and in the Bay of Biscay (France) in 2004–2006 demonstrate for the first time that this gadoid species contains drumming muscles. There were differences in drumming muscles weight with body length, sex and maturity stage. This study shows that the difference between females and males is primarily manifested during the spawning season, seen both in the French and Norwegian samples. For the mature females the drumming muscles dry weight increases only slightly, if at all, with increase in total length. For mature males there is a corresponding rapid increase. There does not seem to be any consistent difference between the average dry weight of the drumming muscles in immature male and immature and mature female hake of the same length, tested on the Norwegian samples. Our results suggest that male hake, like the males of other gadoids studied, may produce sounds in the context of spawning

Identifying modeled ship noise hotspots for marine mammals of Canada's Pacific region

RW was supported by a Marie Curie International Incoming Fellowship within the 7th European Community Framework Programme (Project CONCEAL, FP7, PIIF-GA-2009-253407). These analyses were funded by a grant to RW and EA from Marisla Foundation.The inshore, continental shelf waters of British Columbia (BC), Canada are busy with ship traffic. South coast waters are heavily trafficked by ships using the ports of Vancouver and Seattle. North coast waters are less busy, but expected to get busier based on proposals for container port and liquefied natural gas development and expansion. Abundance estimates and density surface maps are available for 10 commonly seen marine mammals, including northern resident killer whales, fin whales, humpback whales, and other species with at-risk status under Canadian legislation. Ship noise is the dominant anthropogenic contributor to the marine soundscape of BC, and it is chronic. Underwater noise is now being considered in habitat quality assessments in some countries and in marine spatial planning. We modeled the propagation of underwater noise from ships and weighted the received levels by species-specific audiograms. We overlaid the audiogram-weighted maps of ship audibility with animal density maps. The result is a series of so-called "hotspot'' maps of ship noise for all 10 marine mammal species, based on cumulative ship noise energy and average distribution in the boreal summer. South coast waters (Juan de Fuca and Haro Straits) are hotspots for all species that use the area, irrespective of their hearing sensitivity, simply due to ubiquitous ship traffic. Secondary hotspots were found on the central and north coasts (Johnstone Strait and the region around Prince Rupert). These maps can identify where anthropogenic noise is predicted to have above-average impact on species-specific habitat, and where mitigation measures may be most effective. This approach can guide effective mitigation without requiring fleet-wide modification in sites where no animals are present or where the area is used by species that are relatively insensitive to ship noise.Publisher PDFPeer reviewe

Male reproductive biology of European hake Merluccius merluccius

The reproductive biology of European hake (Merluccius merluccius) has been studied extensively in the field, but mainly focusing on fecundity regulation in females and its implications for the fishery. The European hake is highly important commercially throughout its geographical range. Because catches have been decreasing since the 1960s, interest in hake as a potential aquaculture species has recently increased. However, for successful domestication of hake, a better understanding of its reproductive biology, including sperm biology, is needed for purposes of broodstock management and also for the development of sperm storage techniques, including cryopreservation. The objectives of this thesis were to assess hake sperm quality, including sperm production characteristics and energetics, and to characterize sperm movement parameters such as the percentage of motile cells, sperm velocity and flagellar beats. Changes of these parameters over time following activation were evaluated qualitatively for fresh hake sperm. The effects of i) salinity of the activation medium, ii) survival in relation to short term storage duration at 4°C, and iii) sperm cryopreservation on sperm motility characteristics, as well as the reliance on the sperm’s energetic content, were evaluated. In many other Gadoid species, drumming muscles are an important component of reproductive behaviour in spawning males: the contraction of these muscles associated to the swim-bladder results in an audible ‘drumming’ sound during the courtship of the females. However, the presence of drumming muscles has never been reported for hake. Mature hake collected for the sperm analyses, as well as mature females and immature individuals were thus dissected to investigate the presence of drumming muscles and the existence in mature males of potential correlations between their morphological characteristics and the sperm motility parameters. Hake sperm were collected from mature males caught during the summer-early autumn waters off western Norway and during the winter-early spring in the Bay of Biscay (France). Sperm quality characteristics were assessed after storage at 4°C for 25 ± 14 h for transportation. The total ATP, ADP and AMP concentrations were measured using high-performance liquid chromatography followed by calculation of the Adenylate Energy Charge (AEC). Computer Assisted Sperm Analysis (CASA) was used to measure a series of head parameters characterizing the sperm swimming performances. The flagellar characteristics of spermatozoa were explored by high resolution video images. Dissections of mature and non-mature European hake males and females were conducted to investigate the presence of drumming muscles. Sperm production characteristics were evaluated for both Norwegian (Nw) and French (Fr) sperm samples: sperm volume in ml (Nw: 3.9 ± 4.0; Fr: 2.6 ± 4.0), spermatozoa concentration (in × 109 spermatozoa / ml) (Nw: 6.6 ± 3.2; Fr: 13.9 ± 5.1), spermatocrit in % (Nw: 80.2 ± 3.3; Fr: 81.8 ± 10.7) and total number of spermatozoa (in × 109) (Nw: 23.5 ± 30.0; Fr: 35.1 ± 36.2). Osmolality (349 ± 28 mOsmol / kg) and pH (7.6 ± 0.1) of French samples were also measured. When sperm was activated with 100% filtrated sea water (100 SW), the percentage of motile sperm, the velocity, the straightness of the movement, the flagellar beat frequency, the wave amplitude, the number of flagellar waves and the linearity of flagellar waves shape were initially at maximum but decreased sharply later. As a result, active sperm motility sufficient to allow the sperm to reach and fertilize the egg is limited to only a brief time period post-activation (< 100 sec). When transferred into 50 % sea water diluted with distilled water (50 SW), the percentage of motile sperm and the velocity of the movement increased initially but subsequently reached a maximum followed by a decline. Sperm were motile for a longer duration (up to ca. 1600 s) when activated with an activating medium of lower salinity (50 SW: 498 mOsmol / kg) compared to 100 SW (998 mOsmol / kg) (ca. 450 s). Sperm storage: initial percentage of motile sperm in 100 SW, velocity and straightness of the movement were at maximum after 0.5 - 1 day storage duration and then decreased gradually to reach their minima after about four days. Further, both the Adenylate Energy Charge (AEC = 0.78 ± 0.07) and the Adenosine triphosphate (ATP = 85 ± 80 nmoles × 109 spermatozoa) content decreased with storage duration (minima reached after ca. two days: 0.20 ± 0.09 and 5 ± 4 respectively). Cryopreservation significantly negatively affected the percentage of motile sperm, with 0 - 76.4 % motile sperm following thawing. Dissections of hake fish demonstrated for the first time that this gadoid species contains drumming muscles. The results indicated that sound production by adult hake males was much more frequent during the spawning season than in the rest of the year, i.e., formed a central component of the mating system in this species. The present thesis represents a first step towards a better comprehension of the male reproductive biology of European hake, for which no studies were published. Basic knowledge on sperm biology, including movement characteristics, cell energy but also the effects of salinity on sperm movement were recorded. Based on these descriptive elements, sperm management methods were tested such as short term storage and cryopreservation techniques. While hake exhibited only low sperm production, this was compensated by the fact that hake sperm were actively motile for a relatively long time. While this thesis has increased our knowledge on the sperm characteristics of hake further research is needed on determining the relationship between sperm quality and fertilization success, including after cryopreservation procedures. The availability of a hake broodstock facility would be beneficial for future studies in determining which sexual characteristics (drumming muscles, sperm quality) influence male reproductive success

Nitroxide-mediated polymerization induced self-assembly in emulsion for the industrial development of latexes with well-defined nanoobjects

La synthèse de macroalcoxyamines hydrosolubles à partir d’acide méthacrylique et d’un faible pourcentage de styrène sulfonate de sodium a été étudiée en solution aqueuse. Ces macroalcoxyamines ont été utilisées comme macroamorceurs pour la polymérisation en émulsion sanstensioactif du méthacrylate de méthyle et du méthacrylate de n-butyle avec un faible pourcentage destyrène. Les copolymères diblocs amphiphiles produits s’auto-assemblent in situ et conduisent, en fonction de leur taux d’hydrophilie, à l’obtention de nano-objets présentant des morphologies variées(sphères, fibres, vésicules). La plus intéressante est la morphologie fibrillaire car les suspensions correspondantes présentent des propriétés rhéofluidifiantes à basse concentration et possèdent un comportement viscoélastique à haute concentration. La synthèse de ces latex a été étudiée et développée dans des conditions monotopes les plus proches possibles d’une production industrielle.Water-soluble, SG1-based macroalkoxyamines composed of methacrylic acid with a low percentage of sodium 4-styrene sulfonate were synthesized in aqueous solution. These macroalkoxyamines were used as macroinitiators in the surfactant-free emulsion polymerization ofmethyl methacrylate or n-butyl methacrylate with a low percentage of styrene. The polymerization induced self-assembly of the so-formed amphiphilic block copolymers leads to nanoobjects with various morphologies (spheres, fibers, vesicles), depending on their hydrophilic/hydrophobic balance. The most interesting morphology is the nanofiber type of organization as the suspensions presentshear-thinning properties at low concentration and viscoelastic behavior at high concentration. The synthesis of these latexes was investigated and developed in one-pot conditions in order to allow further production at the industrial scale