Next-generation sequencing library preparation method for identification of RNA viruses on the Ion Torrent Sequencing Platform

High-throughput omics technologies in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic, relapsing intestinal disease. Elucidation of the pathogenic mechanisms of IBD requires high-throughput technologies (HTTs) to effectively obtain and analyze large amounts of data. Recently, HTTs have been widely used in IBD, including genomics, transcriptomics, proteomics, microbiomics, metabolomics and single-cell sequencing. When combined with endoscopy, the application of these technologies can provide an in-depth understanding on the alterations of intestinal microbe diversity and abundance, the abnormalities of signaling pathway-mediated immune responses and functionality, and the evaluation of therapeutic effects, improving the accuracy of early diagnosis and treatment of IBD. This review comprehensively summarizes the development and advancement of HTTs, and also highlights the challenges and future directions of these technologies in IBD research. Although HTTs have made striking breakthrough in IBD, more standardized methods and large-scale dataset processing are still needed to achieve the goal of personalized medicine.

A rabies-related lyssavirus from a Nycticeinops schlieffeni bat with neurological signs, South Africa

We report the coding-complete sequence of a lyssavirus, provisionally designated Phala bat lyssavirus (PBLV), characterized using a metagenomics approach. PBLV was identified in a Nycticeinops schlieffeni bat that exhibited neurological signs and died within 24 hours of admission to a wildlife rehabilitation center in Phalaborwa, South Africa.

Applying next-generation sequencing to unravel the mutational landscape in viral quasispecies

Next-generation sequencing (NGS) has revolutionized the scale and depth of biomedical sciences. Because of its unique ability for the detection of sub-clonal variants within genetically diverse populations, NGS has been successfully applied to analyze and quantify the exceptionally-high diversity within viral quasispecies, and many low-frequency drug- or vaccine-resistant mutations of therapeutic importance have been discovered. Although many works have intensively discussed the latest NGS approaches and applications in general, none of them has focused on applying NGS in viral quasispecies studies, mostly due to the limited ability of current NGS technologies to accurately detect and quantify rare viral variants. Here, we summarize several error-correction strategies that have been developed to enhance the detection accuracy of minority variants. We also discuss critical considerations for preparing a sequencing library from viral RNAs and for analyzing NGS data to unravel the mutational landscape.

Identification and genome characterization of a novel picornavirus from ducks in China

A novel picornavirus, referred to as Duck/FC22/China/2017, was isolated from breeding ducks in China and genetically characterized by conducting metagenomics studies. The complete genome consists of a single-stranded, positive-sense RNA made up of 7448 nucleotides (nt) and follows the common picornavirus genome layout: 5' UTR-VP0-VP3-VP1-2A-2B-2C-3A-3B-3C-3D-3' UTR. A typical type-IV internal ribosomal entry site and a conserved 'barbell-like' structure were identified in the 5' UTR and 3' UTR, respectively. The unique 6423-nt open reading frame was predicted to encode a 2141-amino-acid (aa) polyprotein precursor. A pairwise aa sequence identity comparison and phylogenetic analysis revealed that Duck/FC22/China/2017 is closely related to duck aalivirus, duck hepatitis A virus, turkey avisivirus, and red-crowned crane picornavirus.

Viral infection detection using metagenomics technology in six poultry farms of eastern China

With rapidly increasing animal pathogen surveillance requirements, new technologies are needed for a comprehensive understanding of the roles of pathogens in the occurrence and development of animal diseases. We applied metagenomic technology to avian virus surveillance to study the main viruses infecting six poultry farms in two provinces in eastern China. Cloacal/throat double swabs were collected from 60 birds at each farm according to a random sampling method. The results showed that the method could simultaneously detect major viruses infecting farms, including avian influenza virus, infectious bronchitis virus, Newcastle disease virus, rotavirus G, duck hepatitis B virus, and avian leukemia virus subgroup J in several farms. The test results were consistent with the results from traditional polymerase chain reaction (PCR) or reverse transcription-PCR analyses. Five H9N2 and one H3N8 avian influenza viruses were detected at the farms and were identified as low pathogenic avian influenza viruses according to HA cleavage sites analysis. One detected Newcastle disease virus was classified as Class II genotype I and avirulent type according to F0 cleavage sites analysis. Three avian infectious bronchitis viruses were identified as 4/91, CK/CH/LSC/99I and TC07-2 genotypes by phylogenetic analysis of S1 genes. The viral infection surveillance method using metagenomics technology enables the monitoring of multiple viral infections, which allows the detection of main infectious viruses.