Red Cusk-Eel (Genypterus chilensis) Gut Microbiota Description of Wild and Aquaculture Specimens

Chile has promoted the diversification of aquaculture and red cusk-eel (Genypterus chilensis) is one of the prioritized species. However, many aspects of the biology of the species are unknown or have little information available. These include intestinal microbiota, an element that may play an important role in the nutrition and defense of cultured animals for meat production. This study compares the microbiota composition of the intestinal contents of wild and aquaculture fish to explore the microbial communities present and their potential contribution to the host. DNA was extracted from the intestinal content samples and the V4 region of the 16S rRNA gene was amplified and sequenced using the Ion Torrent platform. After the examination of the sequences, strong differences were found in the composition at the level of phylum, being Firmicutes and Tenericutes the most abundant in aquaculture and wild condition, respectively. At the genus level, the Vagococcus (54%) and Mycoplasma (97%) were the most prevalent in the microbial community of aquaculture and wild condition, respectively. The evaluation of predicted metabolic pathways in these metagenomes showed that in wild condition there is an important presence of lipid metabolism belonging to the unsaturated fatty acid synthesis. In the aquaculture condition, the metabolism of terpenoids and polyketides were relevant. To our knowledge, this is the first study to characterize and compare the intestinal microbiota of red cusk-eel (Genypterus chilensis) of wild and aquaculture origin using high-throughput sequencing.

Rare among Rare: Phenotypes of Uncommon CMT Genotypes

(1) Background: Charcot–Marie–Tooth disease (CMT) is the most frequent form of inherited chronic motor and sensory polyneuropathy. Over 100 CMT causative genes have been identified. Previous reports found PMP22, GJB1, MPZ, and MFN2 as the most frequently involved genes. Other genes, such as BSCL2, MORC2, HINT1, LITAF, GARS, and autosomal dominant GDAP1 are responsible for only a minority of CMT cases. (2) Methods: we present here our records of CMT patients harboring a mutation in one of these rare genes (BSCL2, MORC2, HINT1, LITAF, GARS, autosomal dominant GDAP1). We studied 17 patients from 8 unrelated families. All subjects underwent neurologic evaluation and genetic testing by next-generation sequencing on an Ion Torrent PGM (Thermo Fischer) with a 44-gene custom panel. (3) Results: the following variants were found: BSCL2 c.263A > G p.Asn88Ser (eight subjects), MORC2 c.1503A > T p.Gln501His (one subject), HINT1 c.110G > C p.Arg37Pro (one subject), LITAF c.404C > G p.Pro135Arg (two subjects), GARS c.1660G > A p.Asp554Asn (three subjects), GDAP1 c.374G > A p.Arg125Gln (two subjects). (4) Expanding the spectrum of CMT phenotypes is of high relevance, especially for less common variants that have a higher risk of remaining undiagnosed. The necessity of reaching a genetic definition for most patients is great, potentially making them eligible for future experimentations.

Avanços em testes genéticos pré-implantacionais: revisão de literatura

O desenvolvimento das tecnologias genéticas pré-implantacionais nos permite, hoje, identificar anomalias genéticas hereditárias, realizar triagem em busca de mutações e analisar previamente a viabilidade de um embrião, inclusive conhecer a compatibilidade genética embrionária com a de uma pessoa já nascida e doente, que necessite de um doador compatível. Os testes genéticos pré-implantacionais consistem em um conjunto de técnicas, realizadas após o processo de Fertilização in vitro (FIV) e antes da implantação do embrião. Devido à escassez de artigos na literatura brasileira sobre o assunto, foi desenvolvida uma revisão de literatura, que tem como objetivo explanar sobre os avanços que ocorreram nos últimos 30 anos nos testes utilizados para o diagnóstico genético pré-implantacional (DGPI), esclarecendo e apresentando seus protocolos. Para isso, foram selecionadas as principais técnicas adotadas, sendo elas Nested PCR, Multiplex PCR, qPCR, FISH, aCGH, SNP’s, NGS Ion Torrent e Illumina, além de contextualizar a cronologia dos testes e apresentar todo o contexto ético que os envolve. Para tanto, foram utilizadas 48 referências de língua inglesa, portuguesa e espanhola, em sua maioria datadas entre 2017 a 2021. É fato que o DGPI confere um grande avanço no campo da reprodução assistida e possibilita mulheres com idade avançada ou histórico recorrente de aborto, além de pessoas com anomalias genéticas, terem o DNA de seus embriões analisados antes de sua implantação, permitindo identificar mutações que poderão afetar a saúde do bebê e garantindo a sua compatibilidade com a vida.

From Forensics to Clinical Research: Expanding the Variant Calling Pipeline for the Precision ID mtDNA Whole Genome Panel

Despite a multitude of methods for the sample preparation, sequencing, and data analysis of mitochondrial DNA (mtDNA), the demand for innovation remains, particularly in comparison with nuclear DNA (nDNA) research. The Applied Biosystems™ Precision ID mtDNA Whole Genome Panel (Thermo Fisher Scientific, USA) is an innovative library preparation kit suitable for degraded samples and low DNA input. However, its bioinformatic processing occurs in the enterprise Ion Torrent Suite™ Software (TSS), yielding BAM files aligned to an unorthodox version of the revised Cambridge Reference Sequence (rCRS), with a heteroplasmy threshold level of 10%. Here, we present an alternative customizable pipeline, the PrecisionCallerPipeline (PCP), for processing samples with the correct rCRS output after Ion Torrent sequencing with the Precision ID library kit. Using 18 samples (3 original samples and 15 mixtures) derived from the 1000 Genomes Project, we achieved overall improved performance metrics in comparison with the proprietary TSS, with optimal performance at a 2.5% heteroplasmy threshold. We further validated our findings with 50 samples from an ongoing independent cohort of stroke patients, with PCP finding 98.31% of TSS’s variants (TSS found 57.92% of PCP’s variants), with a significant correlation between the variant levels of variants found with both pipelines.

Evaluation of a Rapid Automated Next Generation Sequencing Assay for Precision Medicine in Acute Myeloid Leukemia

Background: In the last decade there have been significant advances in diagnosing and classifying adult acute myeloid leukemia (AML) based on genomic profiling, enabling risk-stratification and targeted therapies. In 2017 the US FDA approved the first gene mutation targeted therapies for AML with multiple additional targeted therapies since approved or in development. Given the typical acuity of AML at initial presentation however and the current turnaround time for next-generation sequencing (NGS) assays, most patients will start definitive initial therapy before all potentially targetable mutations are known. There is, therefore, a significant need for a fast molecular genotyping test to determine eligibility for personalized therapy in AML. The NCI Myeloid Assay (NMA) is a comprehensive targeted NGS assay on the Ion Torrent Genexus System, a fully automated platform that provides a rapid turnaround time from specimen receipt to clinical reporting. NMA utilizes Thermo Fisher Scientific's Oncomine Myeloid Assay GX and appears ideally suited for use in upcoming AML targeted therapy trials but has yet to be extensively tested in a cohort of AML patient diagnostic samples and compared to a standard targeted "myeloid panel" NGS assay platform (s-NGS). Methods: DNA samples (n=173) extracted from pretreatment bone marrow and/or peripheral blood of adult patients (n=112) diagnosed with de novo AML or high-risk myelodysplastic syndrome (MDS), were blindly tested in parallel using the NMA and s-NGS assays. For the NMA assay, 27.75ng of DNA was put into the Genexus System. All runs, controls, and samples were first analyzed for sequencing quality using established quality control (QC) metrics to assess pass/fail status. For all samples that passed QC metrics, variant results generated by the Ion Torrent Genexus pipeline were manually reviewed prior to being called true positive variants. For the s-NGS, using the ArcherDx Myeloid VariantPlex assay, a DNA input of 50ng was used for library preparation on a dual pre- and post-PCR separated automated liquid-handling workflow. Resulting libraries were sequencing on the Novaseq 6000 (Illumina) and the data analyzed using the Archer Analysis software and filtered as previously described (PMID: 34258102). Results from the two assays were compared for mutations with a variant allele fraction (VAF) >5% occurring in genes of interest in small molecule targeted clinical trials including: FLT3, IDH1, IDH2, JAK2, KIT, NPM1, NRAS, KRAS, and TP53. For FLT3-ITD comparison, the presence or absence of a call by the assay was used. Results: Utilizing a 5% VAF reporting threshold, a total of 171 and 174 variants were detected by NMA and s-NGS assays, respectively. A high rate of concordance was observed between the assays, with NMA detecting 96% of s-NGS variants and s-NGS detecting 95% of NMA variants. The VAF of detected single nucleotide variants was highly correlated (r=0.9848, P<0.0001, Figure 1A). NPM1 mutation VAF values trended lower by s-NGS compared to NMA. We investigated the discordant calls (n=15 total in 11 patients). One patient was correctly identified as having an NRAS p.Gly12 mutation by both approaches, but the resulting mutation was incorrectly annotated by the s-NGS pipeline. Samples from two patients (including one with both blood and marrow tested) were correctly identified as being FLT3 tyrosine kinase domain mutated by both sequencing approaches, although only the major of two missense variants identified by s-NGS was reported by the NMA pipeline. None of these patients, however, would be misclassified. The remaining 11 discordant calls were false negatives (including 6 variants detected by s-NGS but not by NMA). All of these "edge case" variants were detectable by lowering the VAF reporting threshold below 5% (Figure 1B). Conclusions: NMA is an automated sample-to-results workflow that can identify myeloid disorder-associated genomic variants in less than 48 hours from library preparation to clinical reporting. We show that NMA is highly concordant with a standard DNA NGS assay for detecting mutations within recurrently mutated AML genes. Accurate rapid genotyping is required for assignment to initial treatment with targeted therapy, and this technology may be a valuable tool for upcoming clinical trials for patients with myeloid malignancies. Figure 1 Figure 1. Disclosures Zhang: Thermo Fisher Scientific: Current Employment. Sedova: Thermo Fisher Scientific: Current Employment. Huang: Thermo Fisher Scientific: Current Employment. Mittal: Thermo Fisher Scientific: Current Employment. Hatch: Thermo Fisher Scientific: Current Employment. Ni: Thermo Fisher Scientific: Current Employment. Kaznadzey: Thermo Fisher Scientific: Current Employment. Sadis: Thermo Fisher Scientific: Current Employment. Smith: Thermo Fisher Scientific: Current Employment. Williams: Illumina: Other: CRADA. Hourigan: Sellas: Research Funding.

511. Treatment with Molnupiravir in the MOVe-In and MOVe-Out Clinical Trials Results in an Increase in Transition Mutations Across the SARS-CoV-2 Genome

Background Molnupiravir (MOV), (MK-4482, EIDD-2801) is being clinically developed for the treatment of COVID-19 disease caused by SARS-CoV-2. MOV is the orally administered 5′-isobutyrate prodrug of the active, antiviral ribonucleoside analogue, N-hydroxycytidine (NHC, EIDD-1931) which inhibits viral replication by induction of mutations in the viral genome, leading to viral error catastrophe. In 2 clinical studies, hospitalized (MOVe-In) and non-hospitalized (MOVe-Out) participants were treated for 5 days with MOV and followed up to Day 29. Viral RNA isolated from nasal swab samples were sequenced to determine the rate, distribution and type of viral mutations observed after MOV treatment. Methods RNA isolated from nasopharangeal swab samples collected during study conduct was quantified by RT-PCR. Samples containing >22,000 copies/mL of RNA underwent complete genome NGS using the Ion AmpliSeq SARS-CoV-2 research panel and Ion Torrent sequencing. Mutation rates were calculated by determining the number of nucleotide changes observed across the entire genome at Day 3 and/or Day 5 compared to baseline. Results Combined data from both studies showed an increase of ~2-4 fold in the viral mutation rate post-baseline in MOV treated compared with placebo. Mutations were distributed across the entire genome with only a minority being observed in more than one sample. The most frequent mutations were transitions of C to U observed in the highest MOV dose group (800 mg/BID). Conclusion Consistent with the proposed mechanism of action of MOV, an increase in the rate of transition mutations in the virus was observed in post-baseline nasal swab samples from participants treated with MOV compared with placebo. Disclosures Julie Strizki, PhD, Merck & Co., Inc. (Employee, Shareholder) Jay Grobler, PhD, Merck & Co., Inc. (Employee, Shareholder) Ying Zhang, PhD, Merck & Co., Inc. (Employee, Shareholder) Jiejun Du, PhD, Merck & Co., Inc. (Employee, Shareholder) Shunbing Zhao, PhD, Merck & Co., Inc. (Employee, Shareholder) Diane Levitan, PhD, Merck & Co., Inc. (Employee, Shareholder) Alex Therien, PhD, Merck & Co., Inc. (Employee, Shareholder) Joan R. Butterton, MD, Merck Sharp & Dohme Corp. (Employee, Shareholder) Nicholas Murgolo, PhD, Merck & Co., Inc. (Employee, Shareholder)

Detection of antimicrobial resistance genes in urban air

To understand antibiotic resistance in pathogenic bacteria, we need to monitor environmental microbes as reservoirs of antimicrobial resistance genes (ARGs). These bacteria are present in the air and can be investigated with the whole metagenome shotgun sequencing approach. This study aimed to investigate the feasibility of a method for metagenomic analysis of microbial composition and ARGs in the outdoor air. Air samples were collected with a Harvard impactor in the PM10 range at 50 m from a hospital in Budapest. From the DNA yielded from samples of PM10 fraction single-end reads were generated with an Ion Torrent sequencer. During the metagenomic analysis, reads were classified taxonomically. The core bacteriome was defined. Reads were assembled to contigs and the ARG content was analyzed. The dominant genera in the core bacteriome were Bacillus, Acinetobacter, Leclercia and Paenibacillus. Among the identified ARGs best hits were vanRA, Bla1, mphL, Escherichia coli EF-Tu mutants conferring resistance to Pulvomycin, BcI, FosB, and mphM. Despite the low DNA content of the samples of PM10 fraction, the number of detected airborne ARGs was surprisingly high.

Evaluation of the Oncomine Comprehensive Assay v3 panel for the detection of 1p/19q codeletion in oligodendroglial tumours

AimsAccurate assessment of 1p/19q codeletion status in diffuse gliomas is of paramount importance for diagnostic, prognostic and predictive purposes. While targeted next generation sequencing (NGS) has been widely implemented for glioma molecular profiling, its role in detecting structural chromosomal variants is less well established, requiring supplementary informatic tools for robust detection. Herein, we evaluated a commercially available amplicon-based targeted NGS panel (Oncomine Comprehensive Assay v3) for the detection of 1p/19q losses in glioma tissues using an Ion Torrent platform and the standard built-in NGS data analysis pipeline solely.MethodsUsing as little as 20 ng of DNA from formalin-fixed paraffin-embedded tissues, we analysed 25 previously characterised gliomas for multi-locus copy number losses (CNLs) on 1p and 19q, including 11 oligodendrogliomas (ODG) and 14 non-oligodendroglial (non-ODG) controls. Fluorescence in-situ hybridisation (FISH) was used as a reference standard.ResultsThe software confidently detected combined contiguous 1p/19q CNLs in 11/11 ODGs (100% sensitivity), using a copy number cut-off of ≤1.5 and a minimum of 10 amplicons covering the regions. Only partial non-specific losses were identified in non-ODGs (100% specificity). Copy number averages of ODG and non-ODG groups were significantly different (p<0.001). NGS was concordant with FISH and was superior to it in distinguishing partial from contiguous losses indicative of whole-arm chromosomal deletion.ConclusionsThis commercial NGS panel, along with the standard Ion Torrent algorithm, accurately detected 1p/19q losses in ODG samples, obviating the need for specialised custom-made informatic analyses. This can easily be incorporated into routine glioma workflow as an alternative to FISH.

Development of a Custom NGS Panel for the Determination of Bladder Cancer Risk

BackgoundBladder cancer (BCa) is a heterogeneous disease caused by the interaction between environmental and genetic risk factors. The objective of this study was to design a panel that evaluates the role of some selected variants in BCa susceptibility. We are also interested in studying the interaction between environmental and genetic risk factors.MethodsThe case/controls cohort was composed with 249 BCa cases and 255 controls. The designed Bladder cancer hereditary panel (BCHP) is composed of 139 selected variants. These variants were genotyped by an amplification-based targeted Next-Generation Sequencing (NGS) on the Ion Torrent Proton sequencer (Life Technologies, Ion Torrent technology). ResultsWe have found that rs162555, rs2228000, rs10936599, rs710521, rs3752645, rs804276, rs4639, rs4881400 and rs288980 were significantly associated with decreased risk of bladder cancer. However the homozygous genotypes for VPS37C (rs7104333, A/A), MPG (rs1013358, C/C) genes or the heterozygous genotype for ARNT gene (rs1889740, rs2228099, rs2256355, rs2864873), GSTA4 (rs17614751) and APOBR/IL27 (rs17855750) were significantly associated with increased risk of bladder cancer development compared to reference group (OR=2.53, 2.34, 1.99, 2.00, 2.00, 1.47, 1.96 and 2.27 respectively). We have also found that non–smokers patients harboring heterozygous genotypes for ARNT/rs2864873 (A>G), ARNT/ rs1889740 (C>T) or GSTA4/rs17614751 (G to A) were respectively at 2.775, 3.069 and 6.608 –folds increased risk of Bca development compared to non-smokers controls with wild genotypes. Moreover the ARNT CT (rs1889740), ARNT CG (rs2228099), ARNT TC (rs2864873) and GSS GA genotypes were associated with an increased risk of BCa even in absence of professional risk factors. Finally the decision-tree analysis produced a three major BCa class. These three classes were essentially characterized by an intensity of tobacco use more than 20 pack years (PY) and the CYP1A2 (rs762551) genotype. ConclusionsThe determined association between genetic variations in BCa and environmental factors, as well as the effect of studied pathway SNPs in comparison with environmental exposition may provide urologists additional genetic information that may help for clinical assessment and treatment decisions. Nevertheless, the underlying mechanisms through which these genes or SNPs affect the clinical behavior of BCas require further studies.