34 research outputs found

    The tree that hides the forest: Cryptic diversity and phylogenetic relationships in the Palaearctic vector Obsoletus/Scoticus Complex (Diptera: Ceratopogonidae) at the European level

    Get PDF
    Background: Culicoides obsoletus is an abundant and widely distributed Holarctic biting midge species, involved in the transmission of bluetongue virus (BTV) and Schmallenberg virus (SBV) to wild and domestic ruminants. Females of this vector species are often reported jointly with two morphologically very close species, C. scoticus and C. montanus, forming the Obsoletus/Scoticus Complex. Recently, cryptic diversity within C. obsoletus was reported in geographically distant sites. Clear delineation of species and characterization of genetic variability is mandatory to revise their taxonomic status and assess the vector role of each taxonomic entity. Our objectives were to characterize and map the cryptic diversity within the Obsoletus/Scoticus Complex. Methods: Portion of the cox1 mitochondrial gene of 3763 individuals belonging to the Obsoletus/Scoticus Complex was sequenced. Populations from 20 countries along a Palaearctic Mediterranean transect covering Scandinavia to Canary islands (North to South) and Canary islands to Turkey (West to East) were included. Genetic diversity based on cox1 barcoding was supported by 16S rDNA mitochondrial gene sequences and a gene coding for ribosomal 28S rDNA. Species delimitation using a multi-marker methodology was used to revise the current taxonomic scheme of the Obsoletus/Scoticus Complex. Results: Our analysis showed the existence of three phylogenetic clades (C. obsoletus clade O2, C. obsoletus clade dark and one not yet named and identified) within C. obsoletus. These analyses also revealed two intra-specific clades within C. scoticus and raised questions about the taxonomic status of C. montanus. Conclusions: To our knowledge, our study provides the first genetic characterization of the Obsoletus/Scoticus Complex on a large geographical scale and allows a revision of the current taxonomic classification for an important group of vector species of livestock viruses in the Palaearctic region.[Figure not available: See fulltext.

    The tree that hides the forest : cryptic diversity and phylogenetic relationships in the Palaearctic vector Obsoletus/Scoticus Complex (Diptera: Ceratopogonidae) at the European level

    Get PDF
    Correction: Volume: 13 Issue: 1 Article Number: 483 DOI: 10.1186/s13071-020-04349-yBackgroundCulicoides obsoletus is an abundant and widely distributed Holarctic biting midge species, involved in the transmission of bluetongue virus (BTV) and Schmallenberg virus (SBV) to wild and domestic ruminants. Females of this vector species are often reported jointly with two morphologically very close species, C. scoticus and C. montanus, forming the Obsoletus/Scoticus Complex. Recently, cryptic diversity within C. obsoletus was reported in geographically distant sites. Clear delineation of species and characterization of genetic variability is mandatory to revise their taxonomic status and assess the vector role of each taxonomic entity. Our objectives were to characterize and map the cryptic diversity within the Obsoletus/Scoticus Complex.MethodsPortion of the cox1 mitochondrial gene of 3763 individuals belonging to the Obsoletus/Scoticus Complex was sequenced. Populations from 20 countries along a Palaearctic Mediterranean transect covering Scandinavia to Canary islands (North to South) and Canary islands to Turkey (West to East) were included. Genetic diversity based on cox1 barcoding was supported by 16S rDNA mitochondrial gene sequences and a gene coding for ribosomal 28S rDNA. Species delimitation using a multi-marker methodology was used to revise the current taxonomic scheme of the Obsoletus/Scoticus Complex.ResultsOur analysis showed the existence of three phylogenetic clades (C. obsoletus clade O2, C. obsoletus clade dark and one not yet named and identified) within C. obsoletus. These analyses also revealed two intra-specific clades within C. scoticus and raised questions about the taxonomic status of C. montanus.ConclusionsTo our knowledge, our study provides the first genetic characterization of the Obsoletus/Scoticus Complex on a large geographical scale and allows a revision of the current taxonomic classification for an important group of vector species of livestock viruses in the Palaearctic region.Peer reviewe

    Cancer effects of formaldehyde: a proposal for an indoor air guideline value

    Get PDF
    Formaldehyde is a ubiquitous indoor air pollutant that is classified as “Carcinogenic to humans (Group 1)” (IARC, Formaldehyde, 2-butoxyethanol and 1-tert-butoxypropanol-2-ol. IARC monographs on the evaluation of carcinogenic risks to humans, vol 88. World Health Organization, Lyon, pp 39–325, 2006). For nasal cancer in rats, the exposure–response relationship is highly non-linear, supporting a no-observed-adverse-effect level (NOAEL) that allows setting a guideline value. Epidemiological studies reported no increased incidence of nasopharyngeal cancer in humans below a mean level of 1 ppm and peak levels below 4 ppm, consistent with results from rat studies. Rat studies indicate that cytotoxicity-induced cell proliferation (NOAEL at 1 ppm) is a key mechanism in development of nasal cancer. However, the linear unit risk approach that is based on conservative (“worst-case”) considerations is also used for risk characterization of formaldehyde exposures. Lymphohematopoietic malignancies are not observed consistently in animal studies and if caused by formaldehyde in humans, they are high-dose phenomenons with non-linear exposure–response relationships. Apparently, these diseases are not reported in epidemiological studies at peak exposures below 2 ppm and average exposures below 0.5 ppm. At the similar airborne exposure levels in rodents, the nasal cancer effect is much more prominent than lymphohematopoietic malignancies. Thus, prevention of nasal cancer is considered to prevent lymphohematopoietic malignancies. Departing from the rat studies, the guideline value of the WHO (Air quality guidelines for Europe, 2nd edn. World Health Organization, Regional Office for Europe, Copenhagen, pp 87–91, 2000), 0.08 ppm (0.1 mg m−3) formaldehyde, is considered preventive of carcinogenic effects in compliance with epidemiological findings

    Identifying an indoor air exposure limit for formaldehyde considering both irritation and cancer hazards

    Get PDF
    Formaldehyde is a well-studied chemical and effects from inhalation exposures have been extensively characterized in numerous controlled studies with human volunteers, including asthmatics and other sensitive individuals, which provide a rich database on exposure concentrations that can reliably produce the symptoms of sensory irritation. Although individuals can differ in their sensitivity to odor and eye irritation, the majority of authoritative reviews of the formaldehyde literature have concluded that an air concentration of 0.3 ppm will provide protection from eye irritation for virtually everyone. A weight of evidence-based formaldehyde exposure limit of 0.1 ppm (100 ppb) is recommended as an indoor air level for all individuals for odor detection and sensory irritation. It has recently been suggested by the International Agency for Research on Cancer (IARC), the National Toxicology Program (NTP), and the US Environmental Protection Agency (US EPA) that formaldehyde is causally associated with nasopharyngeal cancer (NPC) and leukemia. This has led US EPA to conclude that irritation is not the most sensitive toxic endpoint and that carcinogenicity should dictate how to establish exposure limits for formaldehyde. In this review, a number of lines of reasoning and substantial scientific evidence are described and discussed, which leads to a conclusion that neither point of contact nor systemic effects of any type, including NPC or leukemia, are causally associated with exposure to formaldehyde. This conclusion supports the view that the equivocal epidemiology studies that suggest otherwise are almost certainly flawed by identified or yet to be unidentified confounding variables. Thus, this assessment concludes that a formaldehyde indoor air limit of 0.1 ppm should protect even particularly susceptible individuals from both irritation effects and any potential cancer hazard

    Crystal structure of the tetraaquabis(thiocyanato-κN)cobalt(II)–caffeine–water (1/2/4) co-crystal

    No full text
    In the structure of the title compound [systematic name: tetraaquabis(thiocyanato-κN)cobalt(II)–1,3,7-trimethyl-1,2,3,6-tetrahydro-7H-purine-2,6-dione–water (1/2/4)], [Co(NCS)2(H2O)4]·2C8H10N4O2·4H2O, the cobalt(II) cation lies on an inversion centre and is coordinated in a slightly distorted octahedral geometry by the oxygen atoms of four water molecules and two N atoms of two trans-arranged thiocyanate anions. In the crystal, the complex molecules interact with the caffeine molecules through O—H...N, O—H...O and C—H...S hydrogen bonds and π–π interactions [centroid-to-centroid distance = 3.4715 (5) Å], forming layers parallel to the ab plane, which are further connected into a three-dimensional network by O—H...O and O—H...S hydrogen bonds involving the non-coordinating water molecules

    Synthesis, spectroscopic properties, crystal structure, antimicrobial properties and molecular docking studies of the complex (1) 3(C36H24MnN6)·6(PF6). 0.5H2O

    No full text
    International audienceThe complex (1) of general formula 3(C36H24MnN6)·6(F6P). 0.5H2O was prepared and characterized by IR, UV–visible spectroscopy and single crystal X-ray structure analysis. The complex (1) is crystallized in the monoclinic system (z = 2) with space group of P 2/c, the unit cell parameters are a = 15.1490(3) Å, b = 15.2154(2) Å, c = 23.1114(3) Å, β = 90.5152°, and V = 5326.92 Å3. The asymmetric unit contains one and a half Manganese (II) complex (2) [Mn(II)(C12H8N2)3]2+; one of the cations having crystallographic twofold rotational symmetry. Each Mn (II) is pseudo-octahedrally coordinated by three 1,10-phenanthroline molecules with Mn-N distances included between 1.96 and 1.99 Å. Besides, the intermolecular hydrogen bonds: CH⋯F, CH⋯O and π-π interactions are together playing a vital role in the stabilization of the crystal packing. In addition, the antibacterial activity of the complex (1) was evaluated against some bacterial species: Escherichia coli, Staphylococcus aureus, Klebsiella pneumonia, Bacillus Spp, Serratia marcescens, Acinetobacter Bounannue, Staphylococcus saprophiticus; and the antifungal activity against: Aaspergillus niger, Aspergillus spp, Aspergillus nidulans and Candida albicanse. Finally, the 1,10-phenanthroline was docked against various target proteins from diverse bacterial species 1E15 (S. marcescens), 3BU2 (S. saprophiticus), 3GFX (klipsila pnumani), 1BY3 (E. coli) and 5IDV (acinetobacter baumannii) to confirm those obtained results from antibacterial activity. In short, the results of synthesized complex (1) can be exploited in medical field

    Prospective life cycle assessment of metal commodities obtained from deep-sea polymetallic nodules

    No full text
    Sustainable metal supply will be essential to achieve climate and sustainability goals (e.g., Paris agreement), for instance by providing the necessary raw materials for renewable energy infrastructure systems. The potential exploitation of mineral resources from the deep sea (e.g., polymetallic nodules) can play a major role in this supply. A holistic environmental analysis is needed, in order to consider the entire value chain of the products obtained out of deep-sea exploitation. Therefore, the objective of this study was to perform a prospective life cycle assessment (LCA) of deep-sea-sourced commodities and compare it to equivalent products obtained from terrestrial mining. It considered as reference flow one tonne of (dry) nodules, using a cradle-to-gate approach up to the final metal commodities, analyzing the delivery to the market of 10.5 kg of copper, 12.8 kg of nickel, 2.3 kg of cobalt and 311.3 kg of ferromanganese. Three environmental impact categories were analyzed, i.e., climate change, acidification and photochemical oxidant formation. Overall, onshore activities (e.g., hydrometallurgical processing) are the main hotspots for environmental impacts of metals sourced from the deep sea; offshore activities play a minor role in the value chain. While photochemical oxidant formation impacts would be similar to terrestrial alternatives, the deep-sea-sourced commodities can bring environmental gains in the order of 38% for climate change and up to 72% for acidification. As this study shows, a strategic selection of the location for onshore processing of the polymetallic nodules is key to target cleaner production, not only because of the distance from the nodules site, but especially because of the available energy mix. The results should be interpreted with care, though, due to intrinsic limitations of the LCA study, e.g., the prospective nature of this study, the limited access to terrestrial mining data, amongst others. Nonetheless, regardless the limitations a prospective LCA imposes, this study highlights some important potential benefits that commodities from deep-sea polymetallic nodules can bring to society with respect to three important environmental impacts
    corecore