Field-evolved resistance to imidacloprid and ethiprole in populations of brown planthopper Nilaparvata lugens collected from across South and East Asia

This is the final version of the article. Available from Wiley via the DOI in this record.BACKGROUND: We report on the status of imidacloprid and ethiprole resistance in Nilaparvata lugens Stål collected from across South and East Asia over the period 2005-2012. RESULTS: A resistance survey found that field populations had developed up to 220-fold resistance to imidacloprid and 223-fold resistance to ethiprole, and that many of the strains collected showed high levels of resistance to both insecticides. We also found that the cytochrome P450 CYP6ER1 was significantly overexpressed in 12 imidacloprid-resistant populations tested when compared with a laboratory susceptible strain, with fold changes ranging from ten- to 90-fold. In contrast, another cytochrome P450 CYP6AY1, also implicated in imidacloprid resistance, was underexpressed in ten of the populations and only significantly overexpressed (3.5-fold) in a single population from India compared with the same susceptible strain. Further selection of two of the imidacloprid-resistant field strains correlated with an approximate threefold increase in expression of CYP6ER1. CONCLUSIONS: We conclude that overexpression of CYP6ER1 is associated with field-evolved resistance to imidacloprid in brown planthopper populations in five countries in South and East Asia.This work was funded by Bayer CropScience. Rothamsted Research receives grant-aided support from the Biotechnology and Biosciences Research Council of the United Kingdom

Constraining modified gravity with weak-lensing peaks

\ua9 2024 The Author(s)It is well established that maximizing the information extracted from upcoming and ongoing stage-IV weak-lensing surveys requires higher order summary statistics that complement the standard two-point statistics. In this work, we focus on weak-lensing peak statistics to test two popular modified gravity models, f(R) and nDGP, using the FORGE and BRIDGE weak-lensing simulations, respectively. From these simulations, we measure the peak statistics as a function of both cosmological and modified gravity parameters simultaneously. Our findings indicate that the peak abundance is sensitive to the strength of modified gravity, while the peak two-point correlation function is sensitive to the nature of the screening mechanism in a modified gravity model. We combine these simulated statistics with a Gaussian Process Regression emulator and a Gaussian likelihood to generate stage-IV forecast posterior distributions for the modified gravity models. We demonstrate that, assuming small scales can be correctly modelled, peak statistics can be used to distinguish general relativity from f(R) and nDGP models at the 2σ level with a stage-IV survey area of 300 and 1000 deg2, respectively. Finally, we show that peak statistics can constrain log10 (|fR0|) = −6 per cent to 2 per cent precision, and log10(H0rc) = 0.5 per cent to 25 per cent precision

A CRISPR/Cas9 mediated point mutation in the alpha 6 subunit of the nicotinic acetylcholine receptor confers resistance to spinosad in Drosophila melanogaster.

This is the final version of the article. Available from the publisher via the DOI in this record.Open Access funded by Biotechnology and Biological Sciences Research CouncilSpinosad, a widely used and economically important insecticide, targets the nicotinic acetylcholine receptor (nAChRs) of the insect nervous system. Several studies have associated loss of function mutations in the insect nAChR α6 subunit with resistance to spinosad, and in the process identified this particular subunit as the specific target site. More recently a single non-synonymous point mutation, that does not result in loss of function, was identified in spinosad resistant strains of three insect species that results in an amino acid substitution (G275E) of the nAChR α6 subunit. The causal role of this mutation has been called into question as, to date, functional evidence proving its involvement in resistance has been limited to the study of vertebrate receptors. Here we use the CRISPR/Cas9 gene editing platform to introduce the G275E mutation into the nAChR α6 subunit of Drosophila melanogaster. Reverse transcriptase-PCR and sequencing confirmed the presence of the mutation in Dα6 transcripts of mutant flies and verified that it does not disrupt the normal splicing of the two exons in close vicinity to the mutation site. A marked decrease in sensitivity to spinosad (66-fold) was observed in flies with the mutation compared to flies of the same genetic background minus the mutation, clearly demonstrating the functional role of this amino acid substitution in resistance to spinosad. Although the resistance levels observed are 4.7-fold lower than exhibited by a fly strain with a null mutation of Dα6, they are nevertheless predicated to be sufficient to result in resistance to spinosad at recommended field rates. Reciprocal crossings with susceptible fly strains followed by spinosad bioassays revealed G275E is inherited as an incompletely recessive trait, thus resembling the mode of inheritance described for this mutation in the western flower thrips, Frankliniella occidentalis. This study both resolves a debate on the functional significance of a target-site mutation and provides an example of how recent advances in genome editing can be harnessed to study insecticide resistance.This work was, in part, funded by a research grant (BB/G023352/1) from the Biotechnology and Biological Sciences Research Council of the UK to CB

Host plant adaptation in the polyphagous whitefly, Trialeurodes vaporariorum, is associated with transcriptional plasticity and altered sensitivity to insecticides

This is the final version. Available from BMC via the DOI in this record. Background: The glasshouse whitefly, Trialeurodes vaporariorum, is a damaging crop pest and an invasive generalist capable of feeding on a broad range of host plants. As such this species has evolved mechanisms to circumvent the wide spectrum of anti-herbivore allelochemicals produced by its host range. T. vaporariorum has also demonstrated a remarkable ability to evolve resistance to many of the synthetic insecticides used for control. Results: To gain insight into the molecular mechanisms that underpin the polyphagy of T. vaporariorum and its resistance to natural and synthetic xenobiotics, we sequenced and assembled a reference genome for this species. Curation of genes putatively involved in the detoxification of natural and synthetic xenobiotics revealed a marked reduction in specific gene families between this species and another generalist whitefly, Bemisia tabaci. Transcriptome profiling of T. vaporariorum upon transfer to a range of different host plants revealed profound differences in the transcriptional response to more or less challenging hosts. Large scale changes in gene expression (> 20% of genes) were observed during adaptation to challenging hosts with a range of genes involved in gene regulation, signalling, and detoxification differentially expressed. Remarkably, these changes in gene expression were associated with significant shifts in the tolerance of host-adapted T. vaporariorum lines to natural and synthetic insecticides. Conclusions: Our findings provide further insights into the ability of polyphagous insects to extensively reprogram gene expression during host adaptation and illustrate the potential implications of this on their sensitivity to synthetic insecticides.ER

Participant recruitment to FiCTION, a primary dental care trial – survey of facilitators and barriers

Objective To identify reasons behind a lower than expected participant recruitment rate within the FiCTION trial, a multi-centre paediatric primary dental care randomised controlled trial (RCT). Subjects (materials) and methods An online survey, based on a previously published tool, consisting of both quantitative and qualitative responses, completed by staff in dental practices recruiting to FiCTION. Ratings from quantitative responses were aggregated to give overall scores for factors related to participant recruitment. Qualitative responses were independently grouped into themes. Results Thirty-nine anonymous responses were received. Main facilitators related to the support received from the central research team and importance of the research question. The main barriers related to low child eligibility rates and the integration of trial processes within routine workloads. Conclusions These findings have directed strategies for enhancing participant recruitment at existing practices and informed recruitment of further practices. The results help provide a profile of the features required of practices to successfully screen and recruit participants. Future trials in this setting should consider the level of interest in the research question within practices, and ensure trial processes are as streamlined as possible. Research teams should actively support practices with participant recruitment and maintain enthusiasm among the entire practice team

ERK1/2 signaling dominates over RhoA signaling in regulating early changes in RNA expression induced by endothelin-1 in neonatal rat cardiomyocytes

Cardiomyocyte hypertrophy is associated with changes in gene expression. Extracellular signal-regulated kinases 1/2 (ERK1/2) and RhoA [activated by hypertrophic agonists (e.g. endothelin-1)] regulate gene expression and are implicated in the response, but their relative significance in regulating the cardiomyocyte transcriptome is unknown. Our aim was to establish the significance of ERK1/2 and/or RhoA in the early cardiomyocyte transcriptomic response to endothelin-1.Cardiomyocytes were exposed to endothelin-1 (1 h) with/without PD184352 (to inhibit ERK1/2) or C3 transferase (C3T, to inhibit RhoA). RNA expression was analyzed using microarrays and qPCR. ERK1/2 signaling positively regulated approximately 65% of the early gene expression response to ET-1 with a small (approximately 2%) negative effect, whereas RhoA signaling positively regulated approximately 10% of the early gene expression response to ET-1 with a greater (approximately 14%) negative contribution. Of RNAs non-responsive to endothelin-1, 66 or 448 were regulated by PD184352 or C3T, respectively, indicating that RhoA had a more significant effect on baseline RNA expression. mRNAs upregulated by endothelin-1 encoded a number of receptor ligands (e.g. Ereg, Areg, Hbegf) and transcription factors (e.g. Abra/Srf) that potentially propagate the response.ERK1/2 dominates over RhoA in the early transcriptomic response to endothelin-1. RhoA plays a major role in maintaining baseline RNA expression but, with upregulation of Abra/Srf by endothelin-1, RhoA may regulate changes in RNA expression over longer times. Our data identify ERK1/2 as a more significant node than RhoA in regulating the early stages of cardiomyocyte hypertrophy

Human neutrophil clearance of bacterial pathogens triggers anti-microbial gamma delta T cell responses in early infection

Human blood Vc9/Vd2 T cells, monocytes and neutrophils share a responsiveness toward inflammatory chemokines and are rapidly recruited to sites of infection. Studying their interaction in vitro and relating these findings to in vivo observations in patients may therefore provide crucial insight into inflammatory events. Our present data demonstrate that Vc9/Vd2 T cells provide potent survival signals resulting in neutrophil activation and the release of the neutrophil chemoattractant CXCL8 (IL-8). In turn, Vc9/Vd2 T cells readily respond to neutrophils harboring phagocytosed bacteria, as evidenced by expression of CD69, interferon (IFN)-c and tumor necrosis factor (TNF)-a. This response is dependent on the ability of these bacteria to produce the microbial metabolite (E)-4-hydroxy-3-methyl-but-2-enyl pyrophosphate (HMB-PP), requires cell-cell contact of Vc9/Vd2 T cells with accessory monocytes through lymphocyte function-associated antigen-1 (LFA-1), and results in a TNF-a dependent proliferation of Vc9/Vd2 T cells. The antibiotic fosmidomycin, which targets the HMB-PP biosynthesis pathway, not only has a direct antibacterial effect on most HMB-PP producing bacteria but also possesses rapid anti-inflammatory properties by inhibiting cd T cell responses in vitro. Patients with acute peritoneal-dialysis (PD)-associated bacterial peritonitis – characterized by an excessive influx of neutrophils and monocytes into the peritoneal cavity – show a selective activation of local Vc9/Vd2 T cells by HMB-PP producing but not by HMB-PP deficient bacterial pathogens. The cd T celldriven perpetuation of inflammatory responses during acute peritonitis is associated with elevated peritoneal levels of cd T cells and TNF-a and detrimental clinical outcomes in infections caused by HMB-PP positive microorganisms. Taken together, our findings indicate a direct link between invading pathogens, neutrophils, monocytes and microbe-responsive cd T cells in early infection and suggest novel diagnostic and therapeutic approaches.Martin S. Davey, Chan-Yu Lin, Gareth W. Roberts, Sinéad Heuston, Amanda C. Brown, James A. Chess, Mark A. Toleman, Cormac G.M. Gahan, Colin Hill, Tanya Parish, John D. Williams, Simon J. Davies, David W. Johnson, Nicholas Topley, Bernhard Moser and Matthias Eber

Gauge-Higgs Unification In Spontaneously Created Fuzzy Extra Dimensions

We propose gauge-Higgs unification in fuzzy extra dimensions as a possible solution to the Higgs naturalness problem. In our approach, the fuzzy extra dimensions are created spontaneously as a vacuum solution of certain four-dimensional gauge theory. As an example, we construct a model which has a fuzzy torus as its vacuum. The Higgs field in our model is associated with the Wilson loop wrapped on the fuzzy torus. We show that the quadratic divergence in the mass of the Higgs field in the one-loop effective potential is absent. We then argue based on symmetries that the quantum corrections to the Higgs mass is suppressed including all loop contributions. We also consider a realization on the worldvolume theory of D3-branes probing $C^3/(Z_N \times Z_N)$ orbifold with discrete torsion.Comment: 1+38 pages, 4 figures v2: refs adde

The 'Switch' study protocol: a randomised-controlled trial of switching to an alternative tumour-necrosis factor (TNF)-inhibitor drug or abatacept or rituximab in patients with rheumatoid arthritis who have failed an initial TNF-inhibitor drug

Background: Rheumatoid Arthritis (RA) is one of the most common autoimmune diseases, affecting approximately 1% of the UK adult population. Patients suffer considerable pain, stiffness and swelling and can sustain various degrees of joint destruction, deformity, and significant functional decline. In addition, the economic burden due to hospitalisation and loss of employment is considerable, with over 50% of patients being work-disabled within 10 years of diagnosis. Despite several biologic disease modifying anti-rheumatic drugs (bDMARD) now available, there is a lack of data to guide biologic sequencing. In the UK, second-line biologic treatment is restricted to a single option, rituximab. The aim of the SWITCH trial is to establish whether an alternative-mechanism-TNF-inhibitor (TNFi) or abatacept are as effective as rituximab in patients with RA who have failed an initial TNFi drug. Methods/Design: SWITCH is a pragmatic, phase IV, multi-centre, parallel-group design, open-label, randomised, controlled trial (RCT) comparing alternative-mechanism-TNFi and abatacept with rituximab in patients with RA who have failed an initial TNFi drug. Participants are randomised in a 1:1:1 ratio to receive alternative mechanism TNFi, (monoclonal antibodies: infliximab, adalimumab, certolizumab or golimumab or the receptor fusion protein, etanercept), abatacept or rituximab during the interventional phase (from randomisation up to week 48). Participants are subsequently followed up to a maximum of 96 weeks, which constitutes the observational phase. The primary objective is to establish whether an alternative-mechanism-TNFi or abatacept are non-inferior to rituximab in terms of disease response at 24 weeks post randomisation. The secondary objectives include the comparison of alternative-mechanism-TNFi and abatacept to rituximab in terms of disease response, quality of life, toxicity, safety and structural and bone density outcomes over a 12-month period (48 weeks) and to evaluate the cost-effectiveness of switching patients to alternative active therapies compared to current practice. Discussion: SWITCH is a well-designed trial in this therapeutic area that aims to develop a rational treatment algorithm to potentially inform personalised treatment regimens (as opposed to switching all patients to only one available (and possibly unsuccessful) therapy), which may lead to long-term improved patient outcomes and gains in population health

DHODH modulates transcriptional elongation in the neural crest and melanoma

Melanoma is a tumour of transformed melanocytes, which are originally derived from the embryonic neural crest. It is unknown to what extent the programs that regulate neural crest development interact with mutations in the BRAF oncogene, which is the most commonly mutated gene in human melanoma1. We have used zebrafish embryos to identify the initiating transcriptional events that occur on activation of human BRAF(V600E) (which encodes an amino acid substitution mutant of BRAF) in the neural crest lineage. Zebrafish embryos that are transgenic for mitfa:BRAF(V600E) and lack p53 (also known as tp53) have a gene signature that is enriched for markers of multipotent neural crest cells, and neural crest progenitors from these embryos fail to terminally differentiate. To determine whether these early transcriptional events are important for melanoma pathogenesis, we performed a chemical genetic screen to identify small-molecule suppressors of the neural crest lineage, which were then tested for their effects on melanoma. One class of compound, inhibitors of dihydroorotate dehydrogenase (DHODH), for example leflunomide, led to an almost complete abrogation of neural crest development in zebrafish and to a reduction in the self-renewal of mammalian neural crest stem cells. Leflunomide exerts these effects by inhibiting the transcriptional elongation of genes that are required for neural crest development and melanoma growth. When used alone or in combination with a specific inhibitor of the BRAF(V600E) oncogene, DHODH inhibition led to a marked decrease in melanoma growth both in vitro and in mouse xenograft studies. Taken together, these studies highlight developmental pathways in neural crest cells that have a direct bearing on melanoma formation