Continuous Cell Lines from the European Biting Midge Culicoides nubeculosus (Meigen, 1830)

Culicoides biting midges (Diptera: Ceratopogonidae) transmit arboviruses of veterinary or medical importance, including bluetongue virus (BTV) and Schmallenberg virus, as well as causing severe irritation to livestock and humans. Arthropod cell lines are essential laboratory research tools for the isolation and propagation of vector-borne pathogens and the investigation of host-vector-pathogen interactions. Here we report the establishment of two continuous cell lines, CNE/LULS44 and CNE/LULS47, from embryos of Culicoides nubeculosus, a midge distributed throughout the Western Palearctic region. Species origin of the cultured cells was confirmed by polymerase chain reaction (PCR) amplification and sequencing of a fragment of the cytochrome oxidase 1 gene, and the absence of bacterial contamination was confirmed by bacterial 16S rRNA PCR. Both lines have been successfully cryopreserved and resuscitated. The majority of cells examined in both lines had the expected diploid chromosome number of 2n = 6. Transmission electron microscopy of CNE/LULS44 cells revealed the presence of large mitochondria within cells of a diverse population, while arrays of virus-like particles were not seen. CNE/LULS44 cells supported replication of a strain of BTV serotype 1, but not of a strain of serotype 26 which is not known to be insect-transmitted. These new cell lines will expand the scope of research on Culicoides-borne pathogens. View Full-Tex

Bird-biting mosquitoes on farms in southern England

Mosquitoes that blood-feed on avian hosts are important vectors of many arthropod-borne viruses (arboviruses). In Europe, these include West Nile virus (WNV), Usutu virus (USUTV) and Sindbis virus. These are all maintained in enzootic bird-mosquito-bird cycles and are important veterinary and medical threats to the UK. Principally, veterinary concerns lie with the risks to domestic animals, such as the incidental spillover infection of horses with WNV which may lead to serious neurological sequelae. Wildlife may also be affected, with certain wild birds being highly susceptible to infection and death with USUTV, although poultry are less susceptible. To date, UK surveillance for these viruses has not yielded evidence of active virus transmission although serological evidence has been reported

An Early Block in the Replication of the Atypical Bluetongue Virus Serotype 26 in Culicoides Cells Is Determined by Its Capsid Proteins

Arboviruses such as bluetongue virus (BTV) replicate in arthropod vectors involved in their transmission between susceptible vertebrate-hosts. The “classical” BTV strains infect and replicate effectively in cells of their insect-vectors (Culicoides biting-midges), as well as in those of their mammalian-hosts (ruminants). However, in the last decade, some “atypical” BTV strains, belonging to additional serotypes (e.g., BTV-26), have been found to replicate efficiently only in mammalian cells, while their replication is severely restricted in Culicoides cells. Importantly, there is evidence that these atypical BTV are transmitted by direct-contact between their mammalian hosts. Here, the viral determinants and mechanisms restricting viral replication in Culicoides were investigated using a classical BTV-1, an “atypical” BTV-26 and a BTV-1/BTV-26 reassortant virus, derived by reverse genetics. Viruses containing the capsid of BTV-26 showed a reduced ability to attach to Culicoides cells, blocking early steps of the replication cycle, while attachment and replication in mammalian cells was not restricted. The replication of BTV-26 was also severely reduced in other arthropod cells, derived from mosquitoes or ticks. The data presented identifies mechanisms and potential barriers to infection and transmission by the newly emerged “atypical” BTV strains in Culicoides

Search for neutral resonances decaying into a Z boson and a pair of b jets or tau leptons

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Detection of single fully infected <i>C. sonorensis</i> among pools of uninfected individuals processed using an optimised Tissuelyser® assay (n = 3 in all cases).

<p>Detection of single fully infected <i>C. sonorensis</i> among pools of uninfected individuals processed using an optimised Tissuelyser® assay (n  = 3 in all cases).</p

Relationship between viral titre (log₁₀ TCID₅₀) and viral RNA quantity (estimated using C_q values generated from sqPCR) in membrane-fed <i>C. sonorensis</i>.

<p>Results are shown for midges tested at different days post infection (dpi). Spearman’s correlation coefficient (ρ) was computed for each time point to compare titres and C_q values. All correlations were significantly (P<0.0.01) different from zero for 3–11 days post infection. In each figure the dashed line indicates the mean C_q value for individuals sampled on day 0.</p

Changes over time in detection of total BTV RNA (as measured by C_q value).

<p>(A) <i>Culicoides sonorensis</i> and (B) <i>C. nubeculosus</i> were fed upon a BTV-1 strain via a membrane based system (note the inverted scales for the y-axes). In each figure the dashed line indicates the mean C_q value for <i>Culicoides</i> sampled on day 0. For <i>C. sonorensis</i> the symbols indicate whether (red down-triangles) or not (blue up-triangles) infectious BTV was isolated from the individual. For <i>C. nubeculosus</i> the symbols indicate whether infectious BTV was detected (red down-triangles) or the individual was not tested for infectious BTV (black circles).</p

Search for Leptoquarks Coupled to Third-Generation Quarks in Proton-Proton Collisions at root s=13 TeV

Three of the most significant measured deviations from standard model predictions, the enhanced decay rate for B → DðÞτν, hints of lepton universality violation in B → KðÞll decays, and the anomalous magnetic moment of the muon, can be explained by the existence of leptoquarks (LQs) with large couplings to third-generation quarks and masses at the TeV scale. The existence of these states can be probed at the LHC in high energy proton-proton collisions. A novel search is presented for pair production of LQs coupled to a top quark and a muon using data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb−1, recorded by the CMS experiment. No deviation from the standard model prediction has been observed and scalar LQs decaying exclusively into tμ are excluded up to masses of 1420 GeV. The results of this search are combined with those from previous searches for LQ decays into tτ and bν, which excluded scalar LQs below masses of 900 and 1080 GeV. Vector LQs are excluded up to masses of 1190 GeV for all possible combinations of branching fractions to tμ, tτ and bν. With this analysis, all relevant couplings of LQs with an electric charge of −1=3 to third-generation quarks are probed for the first time