417 research outputs found

    The effect of habitat composition on sexual conflict in the seaweed flies Coelopa frigida and C. pilipes

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    Despite the recent explosion of interest in sexual conflict, the effect of environmental conditions on the intensity of sexual conflict within populations has been largely ignored. Reproductive encounters within coelopids are characterized by sexual conflict in the form of intense harassment by males, usually resulting in a vigorous premating struggle. We investigated the effect of habitat composition and duration of exposure to oviposition sites on the level of sexual harassment by males and mating success in two species of European seaweed flies, Coelopa frigida and C. pilipes. The wrack beds inhabited by these two species are dominated by two genera of brown algae, Fucus and Laminaria, the relative proportions of which can vary considerably between wrack beds. Fucus is known to stimulate harassment by males, increase copulation duration and induce females to oviposit in both species. In this study Laminaria stimulated a higher level of harassment by male C. frigida than Fucus did. However, a similar effect was not observed in C. pilipes, with the main additional factor affecting harassment in this species being the age of the male. Our study highlights the potential importance of environmental conditions on the intensity of sexual conflict within a population. We discuss the evolutionary significance of these observed effects in seaweed flies

    The mRNA-based reprogramming of fibroblasts from a SOD1\u3csup\u3eE101G\u3c/sup\u3e familial amyotrophic lateral sclerosis patient to induced pluripotent stem cell line UOWi007

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    2020 The Authors Dermal fibroblasts were donated by a 43 year old male patient with clinically diagnosed familial amyotrophic lateral sclerosis (ALS), carrying the SOD1E101G mutation. The induced pluripotent stem cell (iPSC) line UOWi007-A was generated using repeated mRNA transfections for pluripotency transcription factors Oct4, Klf4, Sox2, c-Myc, Lin28 and Nanog. The iPSCs carried the SOD1E101G genotype and had a normal karyotype, expressed expected pluripotency markers and were capable of in vitro differentiation into endodermal, mesodermal and ectodermal lineages. This iPSC line may be useful for investigating familial ALS resulting from a SOD1 E101G mutation

    Limitations of Electromyography in the Assessment of Abdominal Wall Muscle Contractility Following Botulinum Toxin A Injection

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    Purpose: Pre-operative botulinum toxin A (BTA) injection of the lateral obliques aims to facilitate the closure of large ventral hernia defects and decrease the risk of repair breakdown during the critical healing phase. The exact duration of post-operative BTA effect and top-up timing in cases at high risk of recurrence remains uncertain. This study was designed to assess the value of electromyography (EMG) in determining the appropriate time for BTA top-up.Methods: 56 patients underwent ventral hernia repair with pre-operative BTA infiltration of the lateral obliques. Eleven patients at high risk of recurrence considered suitable for BTA top-up were assessed post-operatively with both functional computed tomography (CT) and EMG. CT assessed segmental contractility of each muscle layer. Single-point EMG assessed the activity of individual muscle layers bilaterally in the anterior axillary line.Results: CT showed (i) variable contractility of anterior and posterior muscle segments prior to BTA injection; (ii) absent or incomplete muscle paralysis in over half of all segments; (iii) increased BTA effect on progress scans; and (iv) non-uniform pattern of change in BTA effect between the anterior and posterior muscle. EMG demonstrated modest voluntary activity in most muscle layers. Compared to standard of reference (CT), EMG showed moderate sensitivity (0.62), poor specificity (0.48), poor accuracy (0.57), and incorrect grading in 71% of true positive results.Conclusions: As BTA effect wanes, single-point EMG cannot reliably determine functional muscle status. A novel finding is that BTA-induced paralysis of the abdominal muscles may be remarkably non-uniform in degree, distribution and duration

    Red blood cell tension protects against severe malaria in the Dantu blood group.

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    Malaria has had a major effect on the human genome, with many protective polymorphisms-such as the sickle-cell trait-having been selected to high frequencies in malaria-endemic regions1,2. The blood group variant Dantu provides 74% protection against all forms of severe malaria in homozygous individuals3-5, a similar degree of protection to that afforded by the sickle-cell trait and considerably greater than that offered by the best malaria vaccine. Until now, however, the protective mechanism has been unknown. Here we demonstrate the effect of Dantu on the ability of the merozoite form of the malaria parasite Plasmodium falciparum to invade red blood cells (RBCs). We find that Dantu is associated with extensive changes to the repertoire of proteins found on the RBC surface, but, unexpectedly, inhibition of invasion does not correlate with specific RBC-parasite receptor-ligand interactions. By following invasion using video microscopy, we find a strong link between RBC tension and merozoite invasion, and identify a tension threshold above which invasion rarely occurs, even in non-Dantu RBCs. Dantu RBCs have higher average tension than non-Dantu RBCs, meaning that a greater proportion resist invasion. These findings provide both an explanation for the protective effect of Dantu, and fresh insight into why the efficiency of P. falciparum invasion might vary across the heterogenous populations of RBCs found both within and between individuals.JCR, AM and DK were supported by the Wellcome Trust (206194/Z/17/Z). MPW is funded by a Wellcome Senior Fellowship (108070). TNW is funded through Fellowships awarded by the Wellcome Trust (091758 and 202800). SNK is supported by the Wellcome Trust-funded Initiative to Develop African Research Leaders (IDeAL) early-career postdoctoral fellowship (107769/Z/10/Z), supported through the DELTAS Africa Initiative (DEL-15-003). The Wellcome Trust provides core support to The KEMRI/Wellcome Trust Research Programme, Kilifi, Kenya (084535), Wellcome Sanger Institute, Cambridge, UK (206194/Z/17/Z) and the Wellcome Centre for Human Genetics, Oxford, UK (090532/Z/09/Z, 203141). PC is supported by the Engineering and Physical Sciences Research Council (EPSRC) (EP/R011443/1), and VI is supported by the EPSRC and the Sackler fellowship

    Two complement receptor one alleles have opposing associations with cerebral malaria and interact with α+thalassaemia

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    Malaria has been a major driving force in the evolution of the human genome. In sub-Saharan African populations, two neighbouring polymorphisms in the Complement Receptor One (CR1) gene, named Sl2 and McCb, occur at high frequencies, suggesting selection by malaria. Previous studies have been inconclusive. Using a large case-control study of severe malaria in Kenyan children and statistical models adjusted for confounders, we demonstrate that Sl2 and McCb have opposing malaria associations. The Sl2 polymorphism is associated with markedly reduced odds of cerebral malaria and death, while the McCb polymorphism is associated with increased odds of cerebral malaria. We also identified an unexpected interaction between Sl2 and α+thalassaemia, revealing that the protective association of Sl2 was greatest in children with normal α-globin. The complex relationship between these three mutations may explain previous conflicting findings, and the data highlight the importance of considering genetic interactions in disease-association studies

    Whole genome sequencing for the genetic diagnosis of heterogenous dystonia phenotypes

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    Introduction: Dystonia is a clinically and genetically heterogeneous disorder and a genetic cause is often difficult to elucidate. This is the first study to use whole genome sequencing (WGS) to investigate dystonia in a large sample of affected individuals. Methods: WGS was performed on 111 probands with heterogenous dystonia phenotypes. We performed analysis for coding and non-coding variants, copy number variants (CNVs), and structural variants (SVs). We assessed for an association between dystonia and 10 known dystonia risk variants. Results: A genetic diagnosis was obtained for 11.7% (13/111) of individuals. We found that a genetic diagnosis was more likely in those with an earlier age at onset, younger age at testing, and a combined dystonia phenotype. We identified pathogenic/likely-pathogenic variants in ADCY5 (n = 1), ATM (n = 1), GNAL (n = 2), GLB1 (n = 1), KMT2B (n = 2), PRKN (n = 2), PRRT2 (n = 1), SGCE (n = 2), and THAP1 (n = 1). CNVs were detected in 3 individuals. We found an association between the known risk variant ARSG rs11655081 and dystonia (p = 0.003). Conclusion: A genetic diagnosis was found in 11.7% of individuals with dystonia. The diagnostic yield was higher in those with an earlier age of onset, younger age at testing, and a combined dystonia phenotype. WGS may be particularly relevant for dystonia given that it allows for the detection of CNVs, which accounted for 23% of the genetically diagnosed cases. © 2019 The Author

    PET Tau and Amyloid-β Burden in Mild Alzheimer's Disease: Divergent Relationship with Age, Cognition, and Cerebrospinal Fluid Biomarkers.

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    BACKGROUND: Combining PET amyloid-β (Aβ) and tau imaging may be critical for tracking disease progression in Alzheimer's disease (AD). OBJECTIVE: We sought to characterize the relationship between Aβ and tau ligands as well as with other measures of pathology. METHODS: We conducted a multi-center observational study in early AD (MMSE >20) participants aged 50 to 85 y. The schedule included cognitive assessments (ADAS-Cog) and CSF measurement of Aβ and tau at baseline and 6 months; PET-CT imaging with Aβ ([18F]AV45) and tau ([18F]AV1451) ligands at baseline. RESULTS: 22 participants took part in the study with 20 completing its 6-month duration and 12 having both tau and amyloid PET. The PET biomarker analysis revealed a strong negative correlation between age and tau in multiple regions. Entorhinal cortex tau and age interacted significantly in terms of cognitive change over 6 months which may have been to older participants deteriorating faster despite lower levels of cortical tau. Cortical Aβ associated with entorhinal cortex tau while CSF tau/Aβ ratio correlated strongly with cortical tau but not Aβ. CONCLUSION: The negative relationship between age and cortical tau whereby younger patients with mild AD had relatively greater tau burden is potentially important. It suggests that younger-age onset AD may be primarily driven by tau pathology while AD developing later may depend on a multitude of pathological mechanisms. These data also suggest that PET-tau performs better than PET-amyloid in predicting the best validated AD diagnostic marker- the CSF total tau/Aβ ratio

    Measurement of Epstein-Barr virus DNA load using a novel quantification standard containing two EBV DNA targets and SYBR Green I dye

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    <p>Abstract</p> <p>Background</p> <p>Reactivation of Epstein-Barr virus (EBV) infection may cause serious, life-threatening complications in immunocompromised individuals. EBV DNA is often detected in EBV-associated disease states, with viral load believed to be a reflection of virus activity. Two separate real-time quantitative polymerase chain reaction (QPCR) assays using SYBR Green I dye and a single quantification standard containing two EBV genes, Epstein-Barr nuclear antigen-1 (EBNA-1) and BamHI fragment H rightward open reading frame-1 (BHRF-1), were developed to detect and measure absolute EBV DNA load in patients with various EBV-associated diseases. EBV DNA loads and viral capsid antigen (VCA) IgG antibody titres were also quantified on a population sample.</p> <p>Results</p> <p>EBV DNA was measurable in ethylenediaminetetraacetic acid (EDTA) whole blood, peripheral blood mononuclear cells (PBMCs), plasma and cerebrospinal fluid (CSF) samples. EBV DNA loads were detectable from 8.0 × 10<sup>2 </sup>to 1.3 × 10<sup>8 </sup>copies/ml in post-transplant lymphoproliferative disease (n = 5), 1.5 × 10<sup>3 </sup>to 2.0 × 10<sup>5 </sup>copies/ml in infectious mononucleosis (n = 7), 7.5 × 10<sup>4 </sup>to 1.1 × 10<sup>5 </sup>copies/ml in EBV-associated haemophagocytic syndrome (n = 1), 2.0 × 10<sup>2 </sup>to 5.6 × 10<sup>3 </sup>copies/ml in HIV-infected patients (n = 12), and 2.0 × 10<sup>2 </sup>to 9.1 × 10<sup>4 </sup>copies/ml in the population sample (n = 218). EBNA-1 and BHRF-1 DNA were detected in 11.0% and 21.6% of the population sample respectively. There was a modest correlation between VCA IgG antibody titre and BHRF-1 DNA load (rho = 0.13, p = 0.05) but not EBNA-1 DNA load (rho = 0.11, p = 0.11).</p> <p>Conclusion</p> <p>Two sensitive and specific real-time PCR assays using SYBR Green I dye and a single quantification standard containing two EBV DNA targets, were developed for the detection and measurement of EBV DNA load in a variety of clinical samples. These assays have application in the investigation of EBV-related illnesses in immunocompromised individuals.</p
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