Wellcome Open Research
Latest articles in this journal
New version
Wellcome Open Research, Volume 6; https://doi.org/10.12688/wellcomeopenres.16928.2
Abstract:
Background: The rising prevalence of childhood obesity and dyslipidaemia is a major public health concern due to its association with morbidity and mortality in later life. Previous studies have found that genetic variants inherited at birth can begin to exert their effects on cardiometabolic traits during the early stages of the lifecourse. Methods: In this study, we have conducted genome-wide association studies (GWAS) for eight measures of adiposity and lipids in a cohort of young individuals (mean age 9.9 years, sample sizes=4,202 to 5,766) from the Avon Longitudinal Study of Parents and Children (ALSPAC). These measures were body mass index (BMI), systolic and diastolic blood pressure, high- density and low-density lipoprotein cholesterol, triglycerides, apolipoprotein A-I and apolipoprotein B. We next undertook functional enrichment, pathway analyses and linkage disequilibrium (LD) score regression to evaluate genetic correlations with later-life cardiometabolic diseases. Results: Using GWAS we identified 14 unique loci associated with at least one risk factor in this cohort of age 10 individuals (P<5x10-8), with lipoprotein lipid-associated loci being enriched for liver tissue-derived gene expression and lipid synthesis pathways. LD score regression provided evidence of various genetic correlations, such as childhood systolic blood pressure being genetically correlated with later-life coronary artery disease (rG=0.26, 95% CI=0.07 to 0.46, P=0.009) and hypertension (rG=0.37, 95% CI=0.19 to 0.55, P=6.57x10-5), as well as childhood BMI with type 2 diabetes (rG=0.35, 95% CI=0.18 to 0.51, P=3.28x10-5). Conclusions: Our findings suggest that there are genetic variants inherited at birth which begin to exert their effects on cardiometabolic risk factors as early as age 10 in the life course. However, further research is required to assess whether the genetic correlations we have identified are due to direct or indirect effects of childhood adiposity and lipid traits.
Wellcome Open Research, Volume 8; https://doi.org/10.12688/wellcomeopenres.19100.1
Abstract:
We present a genome assembly from a colony of Cryptosula pallasiana (an encrusting bryozoan; Bryozoa; Gymnolaemata; Cheilostomatida; Cryptosulidae). The genome sequence is 605.6 megabases in span. Most of the assembly is scaffolded into 12 chromosomal pseudomolecules. The mitochondrial genome has also been assembled and is 16.1 kilobases in length.
Wellcome Open Research, Volume 8; https://doi.org/10.12688/wellcomeopenres.19245.1
Abstract:
We present a genome assembly from an individual male Eupithecia dodoneata (the Oak-tree Pug; Arthropoda; Insecta; Lepidoptera; Geometridae). The genome sequence is 353.7 megabases in span. Most of the assembly is scaffolded into 31 chromosomal pseudomolecules, including the assembled Z sex chromosome. The mitochondrial genome has also been assembled and is 15.3 kilobases in length.
Wellcome Open Research, Volume 8; https://doi.org/10.12688/wellcomeopenres.19049.1
Abstract:
Background: Measurement of antibody titers directed against mosquito salivary antigens in blood samples has been proposed as an outcome measure to assess human exposure to vector bites. However, only a handful of antigens have been identified and the specificity and longitudinal dynamics of antibody responses are not well known. We report the protocol of a clinical trial of controlled exposure to mosquito bites that aims to identify and validate biomarkers of exposure to bites of mosquito vector species that transmit malaria and dengue in Southeast Asia and some other parts of the world. Methods: This study is an exploratory factorial randomized control trial of controlled exposure to mosquito bites with 10 arms corresponding to different species (Aedes aegypt, Ae. albopictus, Anopheles dirus, An. maculatus and An. minimus) and numbers of bites (35 or 305 bites in total over 6 weeks). Blood samples will be collected from study participants before, during and after mosquito biting challenges. Candidate peptides will be identified from published literature with antigen prediction algorithms using mosquito DNA sequence data and with immunoblotting assays carried out using protein extracts of dissected mosquito salivary glands and participants samples. Antibody titers against candidate peptides will be determined in participants samples with high-throughput cutting-edge immuno-assays. Quantification of the antibody response profile over time (including an estimate of the decay rate) and the effect of the number of bites on the antibody response will be determined using linear and logistic mixed-effects models for the continuous and the binary response, respectively. Conclusion: This research is expected to generate important knowledge for vector sero-surveillance and evaluation of vector-control interventions against malaria and dengue in the Greater Mekong Subregion. Registration: This study is registered with clinicaltrials.gov (NCT04478370) on July 20th, 2020.
Wellcome Open Research, Volume 8; https://doi.org/10.12688/wellcomeopenres.18868.1
Abstract:
Background: Coastal Kenya has experienced repeated outbreaks of Chikungunya (CHIKV) and Dengue (DENV) viruses mediated by competent Aedes aegypti mosquito populations. These mosquitoes harbor insect specific viruses (ISVs), some of which can prevent arboviral transmission. However, there has been no systematic molecular entomological surveillance in coastal Kenya and the diversity of viruses in local Aedes aegypti populations remains largely unknown. Methods: To obtain a snapshot of the Aedes aegypti viromes from coastal Kenya, we took advantage of a cross-sectional survey of mosquitoes to determine the prevalence of Zika virus. We collected adult mosquitoes using lured Biogent’s sentinel traps at 16 different localities along the Kenyan coast between May to September 2017. Pools of 20 female Aedes aegypti mosquitoes were generated following grouping by morphological characteristics. Presence of arboviruses in the mosquito pools was determined using virus-specific and genera-specific primers with real-time PCR. Metagenomic next generation sequencing (mNGS) on Illumina Miseq and analysis was used to characterize the virome. Results: A total of 16,520 female Aedes aegypti grouped into 826 pools were analysed. Flaviviruses were detected in 69/826 (8.4%) pools by real time PCR. Sequencing generated 8,459/971,754 (0.87%) clean reads that were taxonomically assigned to 16 and 28 viral families and species, respectively. The family Phenuiviridae represented by Phasi Charoen-like phasivirus (PCLV) species was the most prevalent, detected in 64/73 (87%) mosquito pools. No pathogenic viruses were identified by mNGS. Phylogenetic analysis revealed local PCLV and Cell fusing agent virus (CFAV) were distinct from global sequences. Conclusions: Our data provides information about virus diversity and composition of the Aedes aegypti mosquitoes from coastal Kenya and contributes to the body of knowledge of the Aedes aegypti virome. To the best of our knowledge, this is the first study to provide this information from this region.
Wellcome Open Research, Volume 8; https://doi.org/10.12688/wellcomeopenres.19241.1
Abstract:
We present a genome assembly from an individual male Xylota sylvarum (the Golden-tailed Leafwalker; Arthropoda; Insecta; Diptera; Syrphidae). The genome sequence is 534.8 megabases in span. Most of the assembly is scaffolded into five chromosomal pseudomolecules, including the assembled X sex chromosome. The mitochondrial genome has also been assembled and is 16.0 kilobases in length. Gene annotation of this assembly on Ensembl identified 11,993 protein coding genes.
Wellcome Open Research, Volume 8; https://doi.org/10.12688/wellcomeopenres.19057.1
Abstract:
While Adaptive Clinical Trials (ACTs) have grown in prevalence, prominence, and impact, the ethical issues implicit in such trial designs, particularly in the context of public health emergencies, have been afforded relatively scant attention. This work argues that the ethical dimensions of ACTs should be considered at trial conception, factored into the trial’s design, and subject to ongoing evaluation during the trial’s conduct.
Wellcome Open Research, Volume 8; https://doi.org/10.12688/wellcomeopenres.19038.1
Abstract:
Current RNA purification methods widely use silica-based columns that allow quick isolation of high-quality and good quantities of RNA. However, the major limitations include high cost, the requirement of different kits for small RNA isolation, genomic DNA contamination, and not being flexible. Here, we used the in-house RNA isolation reagent (RIR) for cell lysis, followed by RNA precipitation using isopropanol. RNA isolated using the in-house RIR resulted in a similar quantity and quality compared to the commercial TRIzol. Furthermore, the commercial RNA isolation kits with silica-based columns recommend genomic DNA digestion during or after RNA purification, adding time and cost to RNA purification. Here, we developed an optimized in-house protocol for isolating high-quality RNA free of genomic DNA contamination using magnetic silica beads without needing DNase digestion. Additionally, our method purifies total RNA along with the small RNA fraction, including miRNAs, which usually require a separate kit for extraction. Additionally, the RNA prepared with our method was equally suitable for mRNA and miRNA expression analysis using RT-qPCR. Together, the in-house method of RNA isolation using the magnetic silica beads has exhibited comparable or better total RNA extraction compared to commercial kits at a fraction of the cost and across various cells and tissues.
New version
Wellcome Open Research, Volume 7; https://doi.org/10.12688/wellcomeopenres.17950.2
Abstract:
Background: Previous studies using the Avon Longitudinal Study of Parents and Children (ALSPAC) have shown that if men commenced smoking prior to the onset of puberty their sons, their granddaughters and great-granddaughters were more likely to have excess fat (but not lean) mass during childhood, adolescence and early adulthood. In this study we assess associations between ancestral smoking during adolescence (ages 11–16 years) with fat and lean mass of subsequent generations at two ages. Methods: We analysed data on exposures of grandparents and great-grandparents collected by ALSPAC. The outcomes were the fat masses of their grandchildren and great-grandchildren measured at ages 17 and 24. Measures of lean mass were used as controls. Adjustment was made for 8–10 demographic factors using multiple regression. Results: We found associations between adolescent smoking of the paternal grandfathers and the adjusted fat mass of their grandchildren, but no associations with the grandchildren’s lean mass. Grandchildren at age 17 had an average excess fat mass of +1.65 [95% CI +0.04, +3.26] Kg, and at age 24 an average excess of +1.55 [95% CI -0.27, +3.38] Kg. Adolescent smoking by the maternal grandfather showed similar, but weaker, associations: at 17 an average excess fat mass of +1.02 Kg [95% CI -0.20, +2.25] Kg, and at 24 an average excess of +1.28 [95% CI -0.11, +2.66] Kg. There were no pronounced differences between the sexes of the children. For the great-grandparents there were few convincing results, although numbers were small. Conclusions: We have shown associations between grandfathers’ smoking in adolescence and increased fat (but not lean) mass in their children. Confirmation of these associations is required, either in a further data set or by demonstrating the presence of supportive biomarkers.
Wellcome Open Research, Volume 8; https://doi.org/10.12688/wellcomeopenres.19155.1
Abstract:
Background: Ongoing research of the mosquito microbiome aims to uncover novel strategies to reduce pathogen transmission. Sequencing costs, especially for metagenomics, are however still significant. A resource that is increasingly used to gain insights into host-associated microbiomes is the large amount of publicly available genomic data based on whole organisms like mosquitoes, which includes sequencing reads of the host-associated microbes and provides the opportunity to gain additional value from these initially host-focused sequencing projects. Methods: To analyse non-host reads from existing genomic data, we developed a snakemake workflow called MINUUR (Microbial INsights Using Unmapped Reads). Within MINUUR, reads derived from the host-associated microbiome were extracted and characterised using taxonomic classifications and metagenome assembly followed by binning and quality assessment. We applied this pipeline to five publicly available Aedes aegypti genomic datasets, consisting of 62 samples with a broad range of sequencing depths. Results: We demonstrate that MINUUR recovers previously identified phyla and genera and is able to extract bacterial metagenome assembled genomes (MAGs) associated to the microbiome. Of these MAGS, 42 are high-quality representatives with >90% completeness and <5% contamination. These MAGs improve the genomic representation of the mosquito microbiome and can be used to facilitate genomic investigation of key genes of interest. Furthermore, we show that samples with a high number of KRAKEN2 assigned reads produce more MAGs. Conclusions: Our metagenomics workflow, MINUUR, was applied to a range of Aedes aegypti genomic samples to characterise microbiome-associated reads. We confirm the presence of key mosquito-associated symbionts that have previously been identified in other studies and recovered high-quality bacterial MAGs. In addition, MINUUR and its associated documentation are freely available on GitHub and provide researchers with a convenient workflow to investigate microbiome data included in the sequencing data for any applicable host genome of interest.