Metagenomic analyses of 7000 to 5500 years old coprolites excavated from the Torihama shell-mound site in the Japanese archipelago.

Coprolites contain various kinds of ancient DNAs derived from gut micro-organisms, viruses, and foods, which can help to determine the gut environment of ancient peoples. Their genomic information should be helpful in elucidating the interaction between hosts and microbes for thousands of years, as well as characterizing the dietary behaviors of ancient people. We performed shotgun metagenomic sequencing on four coprolites excavated from the Torihama shell-mound site in the Japanese archipelago. The coprolites were found in the layers of the Early Jomon period, corresponding stratigraphically to 7000 to 5500 years ago. After shotgun sequencing, we found that a significant number of reads showed homology with known gut microbe, viruses, and food genomes typically found in the feces of modern humans. We detected reads derived from several types of phages and their host bacteria simultaneously, suggesting the coexistence of viruses and their hosts. The food genomes provide biological evidence for the dietary behavior of the Jomon people, consistent with previous archaeological findings. These results indicate that ancient genomic analysis of coprolites is useful for understanding the gut environment and lifestyle of ancient peoples.

The International Virus Bioinformatics Meeting 2023.

The 2023 International Virus Bioinformatics Meeting was held in Valencia, Spain, from 24-26 May 2023, attracting approximately 180 participants worldwide. The primary objective of the conference was to establish a dynamic scientific environment conducive to discussion, collaboration, and the generation of novel research ideas. As the first in-person event following the SARS-CoV-2 pandemic, the meeting facilitated highly interactive exchanges among attendees. It served as a pivotal gathering for gaining insights into the current status of virus bioinformatics research and engaging with leading researchers and emerging scientists. The event comprised eight invited talks, 19 contributed talks, and 74 poster presentations across eleven sessions spanning three days. Topics covered included machine learning, bacteriophages, virus discovery, virus classification, virus visualization, viral infection, viromics, molecular epidemiology, phylodynamic analysis, RNA viruses, viral sequence analysis, viral surveillance, and metagenomics. This report provides rewritten abstracts of the presentations, a summary of the key research findings, and highlights shared during the meeting.

Women in the European Virus Bioinformatics Center.

Viruses are the cause of a considerable burden to human, animal and plant health, while on the other hand playing an important role in regulating entire ecosystems. The power of new sequencing technologies combined with new tools for processing "Big Data" offers unprecedented opportunities to answer fundamental questions in virology. Virologists have an urgent need for virus-specific bioinformatics tools. These developments have led to the formation of the European Virus Bioinformatics Center, a network of experts in virology and bioinformatics who are joining forces to enable extensive exchange and collaboration between these research areas. The EVBC strives to provide talented researchers with a supportive environment free of gender bias, but the gender gap in science, especially in math-intensive fields such as computer science, persists. To bring more talented women into research and keep them there, we need to highlight role models to spark their interest, and we need to ensure that female scientists are not kept at lower levels but are given the opportunity to lead the field. Here we showcase the work of the EVBC and highlight the achievements of some outstanding women experts in virology and viral bioinformatics.

Extraction of CRISPR-targeted sequences from the metagenome.

Homology-based search is commonly used to uncover mobile genetic elements (MGEs) from metagenomes, but it heavily relies on reference genomes in the database. Here we introduce a protocol to extract CRISPR-targeted sequences from the assembled human gut metagenomic sequences without using a reference database. We describe the assembling of metagenome contigs, the extraction of CRISPR direct repeats and spacers, the discovery of protospacers, and the extraction of protospacer-enriched regions using the graph-based approach. This protocol could extract numerous characterized/uncharacterized MGEs. For complete details on the use and execution of this protocol, please refer to Sugimoto et al. (2021).

Detection of Ancient Viruses and Long-Term Viral Evolution.

The COVID-19 outbreak has reminded us of the importance of viral evolutionary studies as regards comprehending complex viral evolution and preventing future pandemics. A unique approach to understanding viral evolution is the use of ancient viral genomes. Ancient viruses are detectable in various archaeological remains, including ancient people's skeletons and mummified tissues. Those specimens have preserved ancient viral DNA and RNA, which have been vigorously analyzed in the last few decades thanks to the development of sequencing technologies. Reconstructed ancient pathogenic viral genomes have been utilized to estimate the past pandemics of pathogenic viruses within the ancient human population and long-term evolutionary events. Recent studies revealed the existence of non-pathogenic viral genomes in ancient people's bodies. These ancient non-pathogenic viruses might be informative for inferring their relationships with ancient people's diets and lifestyles. Here, we reviewed the past and ongoing studies on ancient pathogenic and non-pathogenic viruses and the usage of ancient viral genomes to understand their long-term viral evolution.

The International Virus Bioinformatics Meeting 2022.

The International Virus Bioinformatics Meeting 2022 took place online, on 23-25 March 2022, and has attracted about 380 participants from all over the world. The goal of the meeting was to provide a meaningful and interactive scientific environment to promote discussion and collaboration and to inspire and suggest new research directions and questions. The participants created a highly interactive scientific environment even without physical face-to-face interactions. This meeting is a focal point to gain an insight into the state-of-the-art of the virus bioinformatics research landscape and to interact with researchers in the forefront as well as aspiring young scientists. The meeting featured eight invited and 18 contributed talks in eight sessions on three days, as well as 52 posters, which were presented during three virtual poster sessions. The main topics were: SARS-CoV-2, viral emergence and surveillance, virus-host interactions, viral sequence analysis, virus identification and annotation, phages, and viral diversity. This report summarizes the main research findings and highlights presented at the meeting.

Comprehensive discovery of CRISPR-targeted terminally redundant sequences in the human gut metagenome: Viruses, plasmids, and more.

Viruses are the most numerous biological entity, existing in all environments and infecting all cellular organisms. Compared with cellular life, the evolution and origin of viruses are poorly understood; viruses are enormously diverse, and most lack sequence similarity to cellular genes. To uncover viral sequences without relying on either reference viral sequences from databases or marker genes that characterize specific viral taxa, we developed an analysis pipeline for virus inference based on clustered regularly interspaced short palindromic repeats (CRISPR). CRISPR is a prokaryotic nucleic acid restriction system that stores the memory of previous exposure. Our protocol can infer CRISPR-targeted sequences, including viruses, plasmids, and previously uncharacterized elements, and predict their hosts using unassembled short-read metagenomic sequencing data. By analyzing human gut metagenomic data, we extracted 11,391 terminally redundant CRISPR-targeted sequences, which are likely complete circular genomes. The sequences included 2,154 tailed-phage genomes, together with 257 complete crAssphage genomes, 11 genomes larger than 200 kilobases, 766 genomes of Microviridae species, 56 genomes of Inoviridae species, and 95 previously uncharacterized circular small genomes that have no reliably predicted protein-coding gene. We predicted the host(s) of approximately 70% of the discovered genomes at the taxonomic level of phylum by linking protospacers to taxonomically assigned CRISPR direct repeats. These results demonstrate that our protocol is efficient for de novo inference of CRISPR-targeted sequences and their host prediction.

Identification of ancient viruses from metagenomic data of the Jomon people.

Ancient DNA studies provide genomic information about the origins, population structures, and physical characteristics of ancient humans that cannot be solely examined by archeological studies. The DNAs extracted from ancient human bones, teeth, or tissues are often contaminated with coexisting bacterial and viral genomes that contain DNA from ancient microbes infecting those of ancient humans. Information on ancient viral genomes is useful in making inferences about the viral evolution. Here, we have utilized metagenomic sequencing data from the dental pulp of five Jomon individuals, who lived on the Japanese archipelago more than 3000 years ago; this is to detect ancient viral genomes. We conducted de novo assembly of the non-human reads where we have obtained 277,387 contigs that were longer than 1000 bp. These contigs were subjected to homology searches against a collection of modern viral genome sequences. We were able to detect eleven putative ancient viral genomes. Among them, we reconstructed the complete sequence of the Siphovirus contig89 (CT89) viral genome. The Jomon CT89-like sequence was determined to contain 59 open reading frames, among which five genes known to encode phage proteins were under strong purifying selection. The host of CT89 was predicted to be Schaalia meyeri, a bacterium residing in the human oral cavity. Finally, the CT89 phylogenetic tree showed two clusters, from both of which the Jomon sequence was separated. Our results suggest that metagenomic information from the dental pulp of the Jomon people is essential in retrieving ancient viral genomes used to examine their evolution.