Daisychain: Search and Interactive Visualisation of Homologs in Genome Assemblies

Daisychain is an interactive graph visualisation and search tool for custom-built gene homology databases. The main goal of Daisychain is to allow researchers working with specific genes to identify homologs in other annotation releases. The gene-centric representation includes local gene neighborhood to distinguish orthologs and paralogs by local synteny. The software supports genome sequences in FASTA format and GFF3 formatted annotation files, and the process of building the homology database requires a minimum amount of user interaction. Daisychain includes an integrated web viewer that can be used for both data analysis and data publishing. The web interface extends KnetMaps.js and is based on JavaScript.

Gene Homologies Identified between Trypanosoma cruzi Antigen 36 and Mammalian TRIM21 Genes Using Bioinformatics Analysis

Background We previously reported that a Human Ro52 gene sequence (TRIM21) produced a significant stretch of protein sequence homologous to T. cruzi Antigen 36 (Ag 36) protein sequence, when Ag 36 was translated in the second reading frame. Comparison of their respective DNA sequences demonstrated a 114 nucleotide region of both genes having ~ 70 percent partial homology. After Ro52 was shown to be an E3 Ubiquitin dependent Type I ligase for transcription factors for Interferon genes, we proposed that the Ag 36 gene, which contains a repetitive motif within it, may function to repress Ro52 in the human heart through RNA interference, or other unknown mechanism, giving rise to autoimmunity found in Chronic Chagas Cardiomyopathy (CCC). Results To test that hypothesis, we compared various mammalian TRIM genes to the T. cruzi Ag 36 DNA sequence using the Needleman-Wunsch algorithm in the http:\\usegalaxy.eu bioinformatics tool base. In addition to human and chimpanzee, TRIM21 comparable gene regions from canine, shrew, ferret, bat, feline, and armadillo, and aardvark showed homology to the gene for Ag 36 ranging from 68 to 30 percent. However, mouse and eight other mammalian species showed no significant homology. Since mice have been shown to have severe cardiac cardiomyopathy after infection, but their TRIM21 was not homologous to Ag 36 in this study, we conclude that the gene homology has no causative link to CCC. Conclusions In addition to human TRIM21, eight mammalian species showed partial gene homology to T. cruzi Ag 36, and some of these have been demonstrated to have CCC. However, rats and mice TRIM21 showed no partial homology to Ag 36. Since these species have been demonstrated to have CCC, the partial gene homology between Ag36 and TRIM 21 may not be causative or associated with CCC, as was originally hypothesized.

Gene Homologies Identified between Trypanosoma cruzi Antigen 36 and Mammalian TRIM21 Genes Using Bioinformatics Analysis

Background: We previously reported that a Human Ro52 gene sequence (TRIM21) produced a significant stretch of protein sequence homologous to T. cruzi Antigen 36 (Ag 36) protein sequence, when Ag 36 was translated in the second reading frame. Comparison of their respective DNA sequences demonstrated a 114 nucleotide region of both genes having ~70 percent partial homology. After Ro52 was shown to be an E3 Ubiquitin dependent Type I ligase for transcription factors for Interferon genes, we proposed that the Ag 36 gene, which contains a repetitive motif within it, may function to repress Ro52 in the human heart through RNA interference, or other unknown mechanism, giving rise to autoimmunity found in Chronic Chagas Cardiomyopathy (CCC).Results: To test that hypothesis, we compared various mammalian TRIM genes to the T. cruzi Ag 36 DNA sequence using the Needleman-Wunsch algorithm in the http:\\usegalaxy.eu bioinformatics tool base. In addition to human and chimpanzee, TRIM21 comparable gene regions from canine, shrew, ferret, bat, feline, and armadillo, and aardvark showed homology to the gene for Ag 36 ranging from 68 to 30 percent. However, mouse and eight other mammalian species showed no significant homology. Since mice have been shown to have severe cardiac cardiomyopathy after infection, but their TRIM21 was not homologous to Ag 36 in this study, we conclude that the gene homology has no causative link to CCC.Conclusions: In addition to human TRIM21, eight mammalian species showed partial gene homology to T. cruzi Ag 36, and some of these have been demonstrated to have CCC. However, rats and mice TRIM21 showed no partial homology to Ag 36. Since these species have been demonstrated to have CCC, the partial gene homology between Ag36 and TRIM 21 may not be causative or associated with CCC, as was originally hypothesized.

CAMITAX: Taxon labels for microbial genomes

Background The number of microbial genome sequences is increasing exponentially, especially thanks to recent advances in recovering complete or near-complete genomes from metagenomes and single cells. Assigning reliable taxon labels to genomes is key and often a prerequisite for downstream analyses. Findings We introduce CAMITAX, a scalable and reproducible workflow for the taxonomic labelling of microbial genomes recovered from isolates, single cells, and metagenomes. CAMITAX combines genome distance–, 16S ribosomal RNA gene–, and gene homology–based taxonomic assignments with phylogenetic placement. It uses Nextflow to orchestrate reference databases and software containers and thus combines ease of installation and use with computational reproducibility. We evaluated the method on several hundred metagenome-assembled genomes with high-quality taxonomic annotations from the TARA Oceans project, and we show that the ensemble classification method in CAMITAX improved on all individual methods across tested ranks. Conclusions While we initially developed CAMITAX to aid the Critical Assessment of Metagenome Interpretation (CAMI) initiative, it evolved into a comprehensive software package to reliably assign taxon labels to microbial genomes. CAMITAX is available under Apache License 2.0 at https://github.com/CAMI-challenge/CAMITAX.

CAMITAX: Taxon labels for microbial genomes

The number of microbial genome sequences is growing exponentially, also thanks to recent advances in recovering complete or near-complete genomes from metagenomes and single cells. Assigning reliable taxon labels to genomes is key and often a prerequisite for downstream analyses. We introduce CAMITAX, a scalable and reproducible workflow for the taxonomic labelling of microbial genomes recovered from isolates, single cells, and metagenomes. CAMI-TAX combines genome distance-, 16S rRNA gene-, and gene homology-based taxonomic assignments with phylogenetic placement. It uses Nextflow to orchestrate reference databases and software containers, and thus combines ease of installation and use with computational re-producibility. We evaluated the method on several hundred metagenome-assembled genomes with high-quality taxonomic annotations from the TARA Oceans project, and show that the ensemble classification method in CAMITAX improved on all individual methods across tested ranks. While we initially developed CAMITAX to aid the Critical Assessment of Metagenome Interpretation (CAMI) initiative, it evolved into a comprehensive software to reliably assign taxon labels to microbial genomes. CAMITAX is available under the Apache License 2.0 at: https://github.com/CAMI-challenge/CAMITAX

Neuraminidase gene homology contributes to the protective activity of influenza vaccines prepared from the influenza virus library

Whole-virus (WV) vaccines from influenza A/duck/Hokkaido/77 (H3N2), and its reassortant strains H3N4, H3N5 and H3N7, which have the same haemagglutinin (HA) gene but different neuraminidase (NA) genes, were prepared from our influenza virus library. Mice were intranasally immunized with equivalent doses of each vaccine (1–0.01 µg per mouse). All of the mice that received the highest dose of each vaccine (1 µg per mouse) showed equivalent high HA-inhibiting (HI) antibody titres and survived the H3N2 challenge viruses. However, mice that received lower doses of vaccine (0.1 or 0.01 µg per mouse) containing a heterologous NA had lower survival rates than those given the H3N2-based vaccine. The lungs of mice challenged with H3N2 virus showed a significantly higher virus clearance rate when the vaccine contained the homologous NA (N2) versus a heterologous NA, suggesting that NA contributed to the protection, especially when the HI antibody level was low. These results suggested that, even if vaccines prepared for a possible upcoming pandemic do not induce sufficient HI antibodies, WV vaccines can still be effective through other matched proteins such as NA.

Molecular identification of the first local dengue fever outbreak in Shenzhen city, China: a potential imported vertical transmission from Southeast Asia?

SUMMARYA suspected dengue fever outbreak occurred in 2010 at a solitary construction site in Shenzhen city, China. To investigate this epidemic, we used serological, molecular biological, and bioinformatics techniques. Of nine serum samples from suspected patients, we detected seven positive for dengue virus (DENV) antibodies, eight for DENV-1 RNA, and three containing live viruses. The isolated virus, SZ1029 strain, was sequenced and confirmed as DENV-1, showing the highest E-gene homology to D1/Malaysia/36000/05 and SG(EHI)DED142808 strains recently reported in Southeast Asia. Further phylogenetic tree analysis confirmed their close relationship. At the epidemic site, we also detected 14 asymptomatic co-workers (out of 291) positive for DENV antibody, and DENV-1-positive mosquitoes. Thus, we concluded that DENV-1 caused the first local dengue fever outbreak in Shenzhen. Because no imported case was identified, the molecular fingerprints of the SZ1029 strain suggest this outbreak may be due to vertical transmission imported from Southeast Asia.