20 research outputs found
The effects of hydrogen sulphide on aquaculture production
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A recombinant koi herpesvirus (KHV) or Cyprinid herpesvirus 3 (CyHV-3) and a vaccine for the prevention of a desease caused by KHV/CyHV-3 in Cyprinus carpio or Cyprinus carpio koi
No full textpeer reviewedThe present invention refers to a recombinant koi herpesvirus (KHV) or Cyprinid herpesvirus 3 (CyHV-3), which is immunogenic in fish, preferably in carps, more preferably in Cyprinus carpio, and to a vaccine for preventive and/or therapeutic treatment of a disease caused by koi herpesvirus (KHV) or CyHV-3. The 5 recombinant herpesvirus is used to confer immunity on fish, preferably on carps, more preferably on Cyprinus carpio, against a disease caused by koi herpesvirus (KHV) or Cyprinid herpesvirus 3 (CyHV-3)
Rapid detection and identification of viral and bacterial fish pathogens using a DNA array‐based multiplex assay
No full textFish diseases can be caused by a variety of diverse organisms, including bacteria, fungi, viruses and protozoa, and pose a universal threat to the ornamental fish industry and aquaculture. The lack of rapid, accurate and reliable means by which fish pathogens can be detected and identified has been one of the main limitations in fish pathogen diagnosis and fish disease management and has consequently stimulated the search for alternative diagnostic techniques. Here, we describe a method based on multiplex and broad‐range PCR amplification combined with DNA array hybridization for the simultaneous detection and identification of all cyprinid herpesviruses (CyHV‐1, CyHV‐2 and CyHV‐3) and some of the most important fish pathogenic Flavobacterium species, including F. branchiophilum, F. columnare and F. psychrophilum. For virus identification, the DNA polymerase and helicase genes were targeted. For bacterial identification, the ribosomal RNA gene was used. The developed methodology permitted 100% specificity for the identification of the target species. Detection sensitivity was equivalent to 10 viral genomes or less than a picogram of bacterial DNA. The utility and power of the array for sensitive pathogen detection and identification in complex samples such as infected tissue is demonstrated in this study
Identification and localization of the structural proteins of anguillid herpesvirus 1
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C=S⋯I halogen bonding interactions in crystalline iodinated dithiole-2-thiones and thiazole-2-thiones
No full textInternational audienceThe propensity of the sp2 sulfur atom in thiones to act as a halogen bond (XB) acceptor is well established with dihalides (I2, IBr or ICl) as XB donors, but has been more rarely explored with organic XB donors. The crystal structures of four iodinated heterocycles, namely, the mono- and diiodo derivatives of 1,3-dithiole-2-thione and N-ethylthiazole-2-thione, offer an opportunity to evaluate the strength and directionality of such C-I⋯S interactions. We describe here the original synthesis of 3-ethyl-5-iodothiazole-2(3H)-thione and 3-ethyl-4,5-diiodothiazole-2(3H)-thione and the solid state structures of the four compounds, with specific attention to the halogen bonds (C-I⋯SC) and hydrogen bonds (C-H⋯I,S) taking place in the crystals, in connection with the peculiarities of the calculated electrostatic surface potential (ESP) of the four molecules. The thione sulfur atoms in thiazole-2-thiones appear as better XB acceptors than in dithiole-2-thiones, with a notable deformation of the charge concentration area. The mono-iodinated derivatives, 4-iodo-1,3-dithiole-2-thione and 3-ethyl-5-iodothiazole-2-thione, are characterized by hydrogen atoms with positive extremum of the electrostatic surface potential comparable to those of the neighboring iodine atoms, illustrating the parallelism between C-I⋯S halogen bonds and the so-called weak C-H⋯I,S hydrogen bonds. © The Royal Society of Chemistry 2016
Molecular investigations of outbreaks of Perch perhabdovirus infections in pike-perch
No full textInternational audienceIn 2016, a total of 5 massive mortality episodes each affecting hundreds of thousands of pike-perch Sander lucioperca larvae occurred at 2 sites in 2 Western European countries. For each episode, perhabdoviruses related to the perch rhabdovirus (PRV) were detected in samples, using either PCR or cell culture combined with PCR. The sequences of the glycoprotein (g), phospho protein (p) and nucleoprotein (n) genes of these samples demonstrated that 2 different genotypes were present at 1 site, each associated with 1 of the 3 episodes. At the other site, a single genotype was associated with the 2 outbreaks. Furthermore, this genotype was strictly identical to 1 genotype involved in the outbreaks of the first site, strongly suggesting a common origin for these 2 viruses. The common origin was confirmed a posteriori because some larvae introduced to both sites had exactly the same geographic origin in Eastern Europe. Taken together, the molecular and epidemiological data suggest that both horizontal and vertical transmission of 2 distinct strains of perhabdoviruses were involved in the various outbreaks affecting pike-perch
Electrophilic•••nucleophilic interactions driving geometric preferences in molecular assembly
No full textInternational audienceMolecular regions of electrophilic (+) and nucleophilic (-) character are usually invoked in molecular assembly, as their electrostatic complementarity is a main driving force to bring molecules together. Whereas Molecular Electrostatic Potential (MESP) is typically mapped on molecular surfaces of iso-electron density to show up most significant electrophilic and nucleophilic regions on isolated or pseudo-isolated molecules, informing about donor···acceptor assemblies,[1-2] this quantity does not permit to understand the full 3D assembly of a single molecule embedded in its molecular environment. Indeed, further secondary electrostatic interactions, which are also involved in the recovering of molecules by their molecular environments, take also place after most significant + and - regions are monopolized by each other. Thus, MESP is not able to give the necessary information to predict the geometric preferences in the 3D molecular organization because after the first assembly the closest molecule modifies the initial MESP magnitudes (by polarization, charge transfer and/or dispersion effects), therefore biasing eventual predictions on secondary assemblies. On the other hand, the Laplacian of the electron density (2) is another scalar function in real space pointing the regions where electrons are locally concentrated (2 < 0) or depleted (2 > 0). The topological analysis of 2 permits to characterize electrophilic and nucleophilic regions in the valence-shell of atoms by characterizing the so-called critical points.[3] At difference of MESP, the 2 function possess a much more local character in its formation, mainly depending on the atom type and its hybridization, modulated by the atomic intramolecular environment.[1,4-5] Accordingly, main characteristic features in an isolated or pseudo-isolated molecule do not qualitatively vary after assembly. In our research we have already noticed that the direction between the critical points that are associated to electrophilic and nucleophilic regions almost correspond to internuclear directions in interatomic interactions involved in the assembly of molecules. [1,4-5] Hence, by-passing the inherent issues associated to MESP, the topological analysis of (2) appears as a reliable electronic descriptor to understand the 3D assembly of molecules.References[1] Shukla, R.; Dhaka, A.;Aubert, E.;Vijayakumar-Syamala, V.;Jeannin, O.; Fourmigué, M.; Espinosa, E.; Cryst. Growth Des. 2020, 20, 7704−7725.[2] Aubert, E.;Nicolas,I.;Jeannin,O.;Fourmigué,M.;Espinosa,E.; Cryst. Growth Des. 2023, 23, 7798−7810[3] Bader, R. F. W. Atoms in Molecules: A Quantum Theory; Oxford University Press: Oxford, 1990.[4] Brezgunova, M.E.; Aubert, E.; Dahaoui, S.; Fertey, P.; Lebegue, S.; Jelsch, C.; Angyan, J. G.; Espinosa, E., Cryst. Growth Des. 2012, 12, 5373−5386.[5] Brezgunova, M.E.; Lieffrig, J.; Aubert, E.; Dahaoui, S.; Fertey, P.; Lebègue, S.; Angyan, J.; Fourmigué, M.; Espinosa, E.; Cryst. Growth Des. 2013, 13, 3283−3289
Sensitivity and permissivity of Cyprinus carpio to cyprinid herpesvirus 3 during the early stages of its development: importance of the epidermal mucus as an innate immune barrier
Get PDFInternational audienceCyprinid herpesvirus 3 (CyHV-3) causes a lethal disease in common and koi carp (Cyprinus carpio). The present study investigated the ability of CyHV-3 to infect common carp during the early stages of its development (from embryos to fingerlings) after inoculation by immersion in water containing the virus. Fish were inoculated at different times after hatching with a pathogenic recombinant CyHV-3 strain expressing luciferase. The sensitivity and permissivity of carp to CyHV-3 were investigated using in vivo bioluminescence imaging. The susceptibility of carp to CyHV-3 disease was investigated by measuring the survival rate. Carp were sensitive and permissive to CyHV-3 infection and susceptible to CyHV-3 disease at all stages of development, but the sensitivity of the two early developmental stages (embryo and larval stages) was limited compared to later stages. The lower sensitivity observed for the early developmental stages was due to stronger inhibition of viral entry into the host by epidermal mucus. In addition, independent of the developmental stage at which inoculation was performed, the localization of light emission suggested that the skin is the portal of CyHV-3 entry. Taken together, the results of the present study demonstrate that carp are sensitive and permissive to CyHV-3 at all stages of development and confirm that the skin is the major portal of entry after inoculation by immersion in infectious water. The results also stress the role of epidermal mucus as an innate immune barrier against pathogens even and especially at the early stages of development
Cloning of the koi herpesvirus genome as an infectious bacterial artificial chromosome demonstrates that disruption of the thymidine kinase locus induces partial attenuation in Cyprinus carpio koi.
No full textpeer reviewedKoi herpesvirus (KHV) is the causative agent of a lethal disease in koi and common carp. In the present study, we describe the cloning of the KHV genome as a stable and infectious bacterial artificial chromosome (BAC) clone that can be used to produce KHV recombinant strains. This goal was achieved by the insertion of a loxP-flanked BAC cassette into the thymidine kinase (TK) locus. This insertion led to a BAC plasmid that was stably maintained in bacteria and was able to regenerate virions when permissive cells were transfected with the plasmid. Reconstituted virions free of the BAC cassette but carrying a disrupted TK locus (the FL
BAC-excised strain) were produced by the transfection of Cre recombinase-expressing cells with the BAC. Similarly, virions with a wild-type revertant TK sequence (the FL BAC revertant strain) were produced by the cotransfection of cells with the BAC and a DNA fragment encoding the wild-type TK sequence. Reconstituted recombinant viruses were compared to the wild-type parental virus in vitro and in vivo. The FL BAC revertant strain and the FL BAC-excised strain replicated comparably to the parental FL strain. The FL BAC revertant strain induced KHV infection in koi carp that was indistinguishable from that induced by the parental strain,
while the FL BAC-excised strain exhibited a partially attenuated phenotype. Finally, the usefulness of the KHV BAC for recombination studies was demonstrated by the production of an ORF16-deleted strain by using prokaryotic recombination technology. The availability of the KHV BAC is an important advance that will allow the study of viral genes involved in KHV pathogenesis, as well as the production of attenuated recombinant candidate vaccines
