Rapid turnaround multiplex sequencing of SARS-CoV-2: comparing tiling amplicon protocol performance

Genome sequencing is pivotal to SARS-CoV-2 surveillance, elucidating the emergence and global dissemination of acquired genetic mutations. Amplicon sequencing has proven very effective for sequencing SARS-CoV-2, but prevalent mutations disrupting primer binding sites have necessitated the revision of sequencing protocols in order to maintain performance for emerging virus lineages. We compared the performance of Oxford Nanopore Technologies (ONT) Midnight and ARTIC tiling amplicon protocols using 196 Delta lineage SARS-CoV-2 clinical specimens, and 71 mostly Omicron lineage samples with S gene target failure (SGTF), reflecting circulating lineages in the United Kingdom during December 2021. 96-plexed nanopore sequencing was used. For Delta lineage samples, ARTIC v4 recovered the greatest proportion of >=90% complete genomes (81.1%; 159/193), followed by Midnight (71.5%; 138/193) and ARTIC v3 (34.1%; 14/41). Midnight protocol however yielded higher average genome recovery (mean 98.8%) than ARTIC v4 (98.1%) and ARTIC v3 (75.4%), resulting in less ambiguous final consensus assemblies overall. Explaining these observations were ARTIC v4's superior genome recovery in low viral titre/high cycle threshold (Ct) samples and inferior performance in high titre/low Ct samples, where Midnight excelled. We evaluated Omicron sequencing performance using a revised Midnight primer mix alongside the latest ARTIC v4.1 primers, head-to-head with the existing commercially available Midnight and ARTIC v4 protocols. The revised protocols both improved considerably the recovery of Omicron genomes and exhibited similar overall performance to one another. Revised Midnight protocol recovered >=90% complete genomes for 85.9% (61/71) of Omicron samples vs. 88.7% (63/71) for ARTIC v4.1. Approximate cost per sample for Midnight (12GBP) is lower than ARTIC (16GBP) while hands-on time is considerably lower for Midnight (~7 hours) than ARTIC protocols (~9.5 hours).

Genetic Diversity and Prevalence of Porcine Circovirus Type 2 in China During 2000-2019

As the major pathogen for porcine circovirus-associated disease (PCVAD), porcine circovirus type 2 (PCV2) is no longer treated as an emerging virus anymore. The wide distribution of PCV2 infection in China causes huge economic losses in the swine industry. Currently, it is generally believed that PCV2 has eight genotypes (PCV2a to PCV2h), with PCV2a, PCV2b, and PCV2d being widely distributed. To comprehensively explore the genetic diversity and prevalence of PCV2 in China, PCV-2 sequences submitted from China in the GenBank database were retrieved. With a total of 714 PCV2 strains were retrieved, we found that early-submitted PCV2 sequences were mainly collected from coastal provinces in the southeast part of China, which may indicate PCV2 was initially circulating in those regions. From 2002 to 2008, PCV2b was the dominant prevalent genotype in those retrieved sequences. From 2009, PCV2d became the dominant genotype in those sequences, dropping a hint that a potential shift of PCV2b to PCV2d might occur in 2009, which is similar to the patterns at the global level. In addition to the PCV2a, PCV2b, and PCV2d genotypes, novel strains were also characterized. We further revealed that the amino acid sequences consistency of PCV2a Cap is higher than those in other genotypes. Together, this study provided clues for the possible prevalent genotypes and dynamics of genetic diversity in China from 2000 to 2019.

COVID-19: Source, Symptoms, Screening, Prevention and Treatment

Background: COVID-19 is an infectious disease caused by the newly acquired SARS-COV2 virus. The disease is rapidly changing, as well as our understanding of the emerging virus. Not knowing what it was at the beginning of the year 2020, scientists have been able to classify, track, classify, and establish diagnostic tests. Severe illness may strike the elderly and those with chronic illnesses, such as heart disease, diabetes, or cancer. Conclusion: Over the past four decades, the emergence of new infectious, global threats has reshaped national and international thinking and the level of public health responses needed to combat these threats. All countries are at risk of new diseases, according to International Health Regulations.

Atovaquone and Berberine Chloride Reduce SARS-CoV-2 Replication In Vitro

Epidemic RNA viruses seem to arise year after year leading to countless infections and devastating disease. SARS-CoV-2 is the most recent of these viruses, but there will undoubtedly be more to come. While effective SARS-CoV-2 vaccines are being deployed, one approach that is still missing is effective antivirals that can be used at the onset of infections and therefore prevent pandemics. Here, we screened FDA-approved compounds against SARS-CoV-2. We found that atovaquone, a pyrimidine biosynthesis inhibitor, is able to reduce SARS-CoV-2 infection in human lung cells. In addition, we found that berberine chloride, a plant-based compound used in holistic medicine, was able to inhibit SARS-CoV-2 infection in cells through direct interaction with the virion. Taken together, these studies highlight potential avenues of antiviral development to block emerging viruses. Such proactive approaches, conducted well before the next pandemic, will be essential to have drugs ready for when the next emerging virus hits.

Identification of novel QTL contributing to barley yellow mosaic resistance in wild barley (Hordeum vulgare spp. spontaneum)

Background Barley yellow mosaic disease (BYMD) caused by Barley yellow mosaic virus (BaYMV) and Barley mild mosaic virus (BaMMV) seriously threatens the production of winter barley. Cultivating and promoting varieties that carry disease-resistant genes is one of the most powerful ways to minimize the disease’s effect on yield. However, as the BYMD virus mutates rapidly, resistance conferred by the two cloned R genes to the virus had been overcome by new virus strains. There is an urgent need for novel resistance genes in barley that convey sustainable resistance to newly emerging virus strains causing BYMD. Results A doubled haploid (DH) population derived from a cross of SRY01 (BYMD resistant wild barley) and Gairdner (BYMD susceptible barley cultivar) was used to explore for QTL of resistance to BYMD in barley. A total of six quantitative trait loci (qRYM-1H, qRYM-2Ha, qRYM-2Hb, qRYM-3H, qRYM-5H, and qRYM-7H) related to BYMD resistance were detected, which were located on chromosomes 1H, 2H, 3H, 5H, and 7H. Both qRYM-1H and qRYM-2Ha were detected in all environments. qRYM-1H was found to be overlapped with rym7, a known R gene to the disease, whereas qRYM-2Ha is a novel QTL on chromosome 2H originated from SRY01, explaining phenotypic variation from 9.8 to 17.8%. The closely linked InDel markers for qRYM-2Ha were developed which could be used for marker-assisted selection in barley breeding. qRYM-2Hb and qRYM-3H were stable QTL for specific resistance to Yancheng and Yangzhou virus strains, respectively. qRYM-5H and qRYM-7H identified in Yangzhou were originated from Gairdner. Conclusions Our work is focusing on a virus disease (barley yellow mosaic) of barley. It is the first report on BYMD-resistant QTL from wild barley accessions. One novel major QTL (qRYM-2Ha) for the resistance was detected. The consistently detected new genes will potentially serve as novel sources for achieving pre-breeding barley materials with resistance to BYMD.

Vitamin D, Zinc and Iron in Adult Patients with Covid-19 and Their Action in the Immune Response as Biomarkers

COVID-19 in 2020 brought challenges to the Brazilian public health system with an emerging virus with respiratory contagion called SARS-CoV-2. There are few studies in Brazil and in some countries, on the increased incidence of certain viral respiratory infections, including H1N1 and coronavirus and their association with low levels of vitamin D, zinc and iron. The aim of this study was to demonstrate that the deficit of vitamin D, zinc and iron has an impact on the infectious process of patients with COVID-19 and to establish new forms of prevention for the worsening of COVID-19 in the human body. Data were collected from medical records and test results from patients being followed up during the treatment period for COVID-19. Patients with low blood levels of vitamin D, zinc and iron during the treatment period of COVID-19 had a higher percentage of worsening and complications requiring hospitalization in intensive care beds. The ingestion of vitamin D, zinc and iron in the treatment period of patients with COVID-19 in addition to being an immunological protector against SARS-CoV-2 and alleviating the process of worsening the disease can also act as a biomarker in cases of this disease.

Specificity of resistance and tolerance to cucumber vein yellowing virus in melon accessions and evidence for resistance breaking associated with a single mutation in VPg

Cucumber vein yellowing virus (CVYV) is an emerging virus on cucurbits in the Mediterranean Basin, against which few resistance sources are available, particularly in melon. The melon accession PI 164323 displays complete resistance to isolate CVYV-Esp, and accession HSD 2458 presents a tolerance, i.e. very mild symptoms in spite of virus accumulation in inoculated plants. The resistance is controlled by a dominant allele Cvy-11, while the tolerance is controlled by a recessive allele cvy-2, independent from Cvy-11. Before introducing the resistance or tolerance in commercial cultivars through a long breeding process, it is important to estimate their specificity and durability. Upon inoculation with eight molecularly diverse CVYV isolates, the resistance was found to be isolate-specific since many CVYV isolates induced necrosis on PI 164323, whereas the tolerance presented a broader range. A resistance-breaking isolate inducing severe mosaic on PI 164323 was obtained. This isolate differed from the parental strain by a single amino acid change in the VPg coding region. An infectious CVYV cDNA clone was obtained, and the effect of the mutation in the VPg cistron on resistance to PI 164323 was confirmed by reverse genetics. This represents the first determinant for resistance-breaking in an ipomovirus. Our results indicate that the use of the Cvy-11 allele alone will not provide durable resistance to CVYV and that, if used in the field, it should be combined with other control methods such as cultural practices and pyramiding of resistance genes to achieve long-lasting resistance against CVYV.

Rapid Response to SARS-CoV-2 in Aotearoa New Zealand: Implementation of a Diagnostic Test and Characterization of the First COVID-19 Cases in the South Island

It has been 20 months since we first heard of SARS-CoV-2, the novel coronavirus detected in the Hubei province, China, in December 2019, responsible for the ongoing COVID-19 pandemic. Since then, a myriad of studies aimed at understanding and controlling SARS-CoV-2 have been published at a pace that has outshined the original effort to combat HIV during the beginning of the AIDS epidemic. This massive response started by developing strategies to not only diagnose individual SARS-CoV-2 infections but to monitor the transmission, evolution, and global spread of this new virus. We currently have hundreds of commercial diagnostic tests; however, that was not the case in early 2020, when just a handful of protocols were available, and few whole-genome SARS-CoV-2 sequences had been described. It was mid-January 2020 when several District Health Boards across New Zealand started planning the implementation of diagnostic testing for this emerging virus. Here, we describe our experience implementing a molecular test to detect SARS-CoV-2 infection, adapting the RT-qPCR assay to be used in a random-access platform (Hologic Panther Fusion® System) in a clinical laboratory, and characterizing the first whole-genome SARS-CoV-2 sequences obtained in the South Island, right at the beginning of the SARS-CoV-2 outbreak in New Zealand. We expect that this work will help us and others prepare for the unequivocal risk of similar viral outbreaks in the future.