Electrophysiological Evaluation of Pacific Oyster (Crassostrea gigas) Sensitivity to Saxitoxin and Tetrodotoxin     

Floriane Boullot  Caroline Fabioux  Hlne Hgaret  Pierre Boudry  Philippe Soudant  Evelyne Benoit 《Marine drugs》2021,19(7)

Pacific oysters (Crassostrea gigas) may bio-accumulate high levels of paralytic shellfish toxins (PST) during harmful algal blooms of the genus Alexandrium. These blooms regularly occur in coastal waters, affecting oyster health and marketability. The aim of our study was to analyse the PST-sensitivity of nerves of Pacific oysters in relation with toxin bio-accumulation. The results show that C. gigas nerves have micromolar range of saxitoxin (STX) sensitivity, thus providing intermediate STX sensitivity compared to other bivalve species. However, theses nerves were much less sensitive to tetrodotoxin. The STX-sensitivity of compound nerve action potential (CNAP) recorded from oysters experimentally fed with Alexandrium minutum (toxic-alga-exposed oysters), or Tisochrysis lutea, a non-toxic microalga (control oysters), revealed that oysters could be separated into STX-resistant and STX-sensitive categories, regardless of the diet. Moreover, the percentage of toxin-sensitive nerves was lower, and the STX concentration necessary to inhibit 50% of CNAP higher, in recently toxic-alga-exposed oysters than in control bivalves. However, no obvious correlation was observed between nerve sensitivity to STX and the STX content in oyster digestive glands. None of the nerves isolated from wild and farmed oysters was detected to be sensitive to tetrodotoxin. In conclusion, this study highlights the good potential of cerebrovisceral nerves of Pacific oysters for electrophysiological and pharmacological studies. In addition, this study shows, for the first time, that C. gigas nerves have micromolar range of STX sensitivity. The STX sensitivity decreases, at least temporary, upon recent oyster exposure to dinoflagellates producing PST under natural, but not experimental environment.  相似文献   

Improved water repellency of black spruce wood surfaces after treatment in carbon tetrafluoride plasmas   总被引：1，自引：0，他引：1  

Bouddah Poaty  Bernard Riedl  Pierre Blanchet  Vincent Blanchard  Luc Stafford 《Wood Science and Technology》2013,47(2):411-422

Plasma treatments for black spruce wood (Picea mariana (Mill.) B.S.P.), a widespread forest species from Canada, were carried out in order to waterproof the exposed surfaces. Experiments were performed using inductively coupled argon plasma with carbon tetrafluoride as the gaseous precursor for plasma-enhanced chemical vapor deposition of functional fluoropolymer coatings on wood. Analysis of the wettability through water contact angle measurements showed water-repellent characteristics, with static contact angles up to 130° depending on plasma exposure time, CF₄ concentration in the Ar/CF₄ plasma, and plasma source-to-substrate distance. X-ray photoelectron spectroscopy investigations of plasma-treated wood surfaces confirmed the growth of a thin, fluorocarbon layer with fluorine atomic concentrations close to 50 % on highly hydrophobic wood surfaces. Estimation of the thickness of the coatings by stylus profilometry revealed that a minimum layer thickness of about 80 nm is required to obtain water repellant wood surfaces with minimum water uptake. This complete set of data indicates that fluorocarbon-containing plasmas represent a very promising approach for improving the durability of wood products in wet and humid conditions.  相似文献   

Anaesthetic induction with alfaxalone may produce hypoxemia in rabbits premedicated with fentanyl/droperidol     

Alexandru C Tutunaru  Alexandru Şonea  Pierre Drion  Didier Serteyn  Charlotte Sandersen 《Veterinary anaesthesia and analgesia》2013,40(6):657-659

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Population structure of the fish pathogen Flavobacterium psychrophilum at whole-country and model river levels in Japan     

Erina Fujiwara-Nagata  Céline Chantry-Darmon  Jean-Fran?ois Bernardet  Mitsuru Eguchi  Eric Duchaud  Pierre Nicolas 《Veterinary research》2013,44(1):34

The bacterium Flavobacterium psychrophilum is a serious problem for salmonid farming worldwide. This study investigates by multilocus sequence typing (MLST) the population structure of this pathogen in Japan where it is also a major concern for ayu, a popular game fish related to salmoniforms. A total of 34 isolates collected across the country and 80 isolates sampled in a single model river by electrofishing were genotyped. The data accounting for 15 fish species allowed identifying 35 distinct sequence types (ST) in Japan. These ST are distinct from those reported elsewhere, except for some ST found in rainbow trout and coho salmon, two fish that have been the subject of intensive international trade. The pattern of polymorphism is, however, strikingly similar across geographical scales (model river, Japan, world) in terms of the fraction of molecular variance linked to the fish host (~50%) and of pairwise nucleotide diversity between ST (~5 Kbp^-1). These observations go against the hypothesis of a recent introduction of F. psychrophilum in Japan. Two findings were made that are important for disease control: 1) at least two independent F. psychrophilum lineages infect ayu and 2) co-infections of the same individual fish by different strains occur.  相似文献   

Assessment of hydraulic properties of technosols using Beerkan and multiple tension disc infiltration methods     

Deniz Yilmaz  Sofia Bouarafa  Pierre‐Emmanuel Peyneau  Rafael Angulo‐Jaramillo  Laurent Lassabatere 《European Journal of Soil Science》2019,70(5):1049-1062

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Carabid beetle (Coleoptera: Carabidae) diversity in the black spruce succession of eastern Canada     

Pierre Paquin 《Biological conservation》2008,141(1):261-275

This study provides the first assessment of carabid beetle diversity in a natural forest context that encompasses a complete black spruce (Picea mariana) natural succession. Boreal forest conservation has been based on several assumptions about forest age that only consider species richness without accounting for species composition. It has also been guided by studies of incomplete chronologies that do not include naturally burned or old-growth stages. Twenty-one forest stands of different ages following fire - from recently burned to old-growth stages (0-340 years of age) - were sampled, revealing a strong relationship between age of forest and diversity of Carabidae. Over time, species richness followed a parabolic U-shaped pattern both with observed (Obs) and predicted richness (ACE). Chronological clustering identified four groups of species in the succession: the ‘burned’ group characterized 0-2-year-old forests, ‘regenerating’ (21-58 year), ‘mature’ (70-170 year) and ‘old-growth’ (177-340 year). The time spans corresponding to each of these assemblages lengthen with age of forest at an exponential rate. Ward’s and K-means (clustering without constraint) provided support for the four assemblages but showed variation between individual successions, particularly for the ‘regenerating’ assemblage, identified as the most heterogeneous. The IndVal method identified characteristic species in every stage of the succession, particularly Sericoda spp. in the burned stage and Dromius piceus and Platynus mannerheimii associated with old-growth stands. The results obtained here show that diversity of Carabidae varies in primeval conditions according to age of forest and such variation should be taken into account when conservation issues are involved.  相似文献   

The role of oxylipins and antioxidants on off-flavor precursor formation during potato flake processing     

Gosset V  Göbel C  Laine G  Delaplace P  du Jardin P  Feussner I  Fauconnier ML 《Journal of agricultural and food chemistry》2008,56(23):11285-11292

The impact of processing on nonenzymatic antioxidant degradation and lipid oxidation leading to off-flavor development in potato flakes during storage was investigated. Lipoxygenase activity measurements in parallel with the analysis of lipid oxidation products (oxylipins) profiles using HPLC showed that the processing conditions used inhibited efficiently enzymatic lipid oxidation. However, nonenzymatic lipid oxidation products were found throughout processing and in fresh potato flakes. Furthermore, these autoxidative processes cannot be inactivated by the main endogenous nonenzymatic antioxidants in potato tubers (ascorbic acid, phenolic compounds and carotenoids), as these antioxidants are degraded during processing. Indeed, leaching and thermal treatments taking place during processing lead to a decrease of about 95%, 82% and 27% in the content of ascorbic acid, phenolic compounds and carotenoids, respectively. Therefore, storage is a critical step to prevent off-flavor development in potato flakes. Specific attention has thus to be paid on the use of efficient exogenous antioxidants as well as on storage conditions.  相似文献   

Synthesis of haptens and conjugates for ELISA of glycitein: development and validation of an immunological test     

Shinkaruk S  Lamothe V  Schmitter JM  Fructus A  Sauvant P  Vergne S  Degueil M  Babin P  Bennetau B  Bennetau-Pelissero C 《Journal of agricultural and food chemistry》2008,56(16):6809-6817

Two carboxylic acid haptens of glycitein were synthesized, with a spacer arm at the C2 position. They differed in the length of the spacer arm, with the length of the spacer arms being three or four carbon atoms, and were named Delta3-glycitein and Delta4-glycitein haptens, respectively. The different haptens were coupled to bovine serum albumin (BSA), and the coupling efficiency was assessed by MALDI mass spectrometry. Polyclonal antibodies were generated against the BSA conjugates. An additional conjugate of Delta4-glycitein hapten was generated with swine thyroglobulin (Thyr). Enzyme-linked immunosorbent assays (ELISAs) based on the competition between free glycitein and Delta4-glycitein-Thyr conjugates for specific antibodies were developed. The IC50 of the standard curves was 15.6 ng mL(-1) with anti-Delta3-glycitein and 62.5 ng mL(-1) with anti-Delta4-glycitein, that is, 10.9 and 44 pmol/well, respectively. With the Delta3-glycitein antibody, interassay and intra-assay variations were 12.2 and 11.5%, respectively. Specificity tests did not show any significant cross-reaction with any other soy isoflavone. This specificity is not influenced by the length of the spacer arm. The assay was validated by measurements performed on plasma samples as well as on soy-based foodstuffs and on soy-based food supplements.  相似文献   

Twin pregnancy experimental model for transvaginal ultrasound-guided twin reduction in mares     

Ignacio Raggio  Réjean C. Lefebvre  Pierre Poitras  Denis Vaillancourt  Alan K. Goff 《The Canadian veterinary journal. La revue veterinaire canadienne》2008,49(11):1093-1098

Multiple pregnancies are still an important cause of noninfectious abortion, stillbirth, neonatal mortality, and significant delays in reproductive performance in mares. Despite new management techniques, reduction in multiple pregnancies is an ongoing preoccupation and challenge for the equine veterinarian. The aim of the present study was to establish a twin pregnancy experimental model in the mare to study the effectiveness of a transvaginal ultrasound-guided embryonic vesicle injection. Mares in heat were inseminated and then received an embryo at day 7 of the estrous cycle. At days 14 and 30, 53.5% (n = 23) and 23% (n = 10) of the mares, respectively, were carrying twins. Twin pregnancies were reduced at day 30 by transvaginal ultrasound-guided puncture of the embryonic vesicle (control, n = 5) or by transvaginal ultrasound-guided injection (TVUEVI) of 25 mg of amikacin into the embryonic vesicle (n = 5). The TVUEVI treatment had a 40% success rate and no significant variations in progesterone and prostaglandin metabolite were observed. Even though the technique does not seem very effective, the experimental model could be useful for clinical research in embryo reduction and early embryonic loss.  相似文献   

Phenotype of macular corneal dystrophy in Labrador Retrievers: A multicenter study     

Claudia Busse  Christiane Kafarnik  Rose Linn‐Pearl  Christelle Volmer  Kaspar Matiasek  Johana E. Premont  Thomas Dulaurent  Jean‐Yves Douet  Ida Gilbert  Sari Jalomäki  Katrin Trost  Pierre‐Francois Isard  Ryan Boyd  Isabelle Raymond 《Veterinary ophthalmology》2019,22(3):294-304

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