Advances in the Xenopus immunome: Diversification, expansion, and contraction.

Xenopus is a genus of African clawed frogs including two species, X. tropicalis and X. laevis that are extensively used in experimental biology, immunology, and biomedical studies. The availability of fully sequenced and annotated Xenopus genomes is strengthening genome-wide analyses of gene families and transgenesis to model human diseases. However, inaccuracies in genome annotation for genes involved in the immune system (i.e., immunome) hamper immunogenetic studies. Furthermore, advanced genome technologies (e.g., single-cell and RNA-Seq) rely on well-annotated genomes. The annotation problems of Xenopus immunome include a lack of established orthology across taxa, merged gene models, poor representation in gene pages on Xenbase, misannotated genes and missing gene IDs. The Xenopus Research Resource for Immunobiology in collaboration with Xenbase and a group of investigators are working to resolve these issues in the latest versions of genome browsers. In this review, we summarize the current problems of previously misannotated gene families that we have recently resolved. We also highlight the expansion, contraction, and diversification of previously misannotated gene families.

Xenbase: key features and resources of the Xenopus model organism knowledgebase.

Xenbase (https://www.xenbase.org/), the Xenopus model organism knowledgebase, is a web-accessible resource that integrates the diverse genomic and biological data from research on the laboratory frogs Xenopus laevis and Xenopus tropicalis. The goal of Xenbase is to accelerate discovery and empower Xenopus research, to enhance the impact of Xenopus research data, and to facilitate the dissemination of these data. Xenbase also enhances the value of Xenopus data through high-quality curation, data integration, providing bioinformatics tools optimized for Xenopus experiments, and linking Xenopus data to human data, and other model organisms. Xenbase also plays an indispensable role in making Xenopus data interoperable and accessible to the broader biomedical community in accordance with FAIR principles. Xenbase provides annotated data updates to organizations such as NCBI, UniProtKB, Ensembl, the Gene Ontology consortium, and most recently, the Alliance of Genomic Resources, a common clearing house for data from humans and model organisms. This article provides a brief overview of key and recently added features of Xenbase. New features include processing of Xenopus high-throughput sequencing data from the NCBI Gene Expression Omnibus; curation of anatomical, physiological, and expression phenotypes with the newly created Xenopus Phenotype Ontology; Xenopus Gene Ontology annotations; new anatomical drawings of the Normal Table of Xenopus development; and integration of the latest Xenopus laevis v10.1 genome annotations. Finally, we highlight areas for future development at Xenbase as we continue to support the Xenopus research community.

The Xenopus phenotype ontology: bridging model organism phenotype data to human health and development.

BACKGROUND: Ontologies of precisely defined, controlled vocabularies are essential to curate the results of biological experiments such that the data are machine searchable, can be computationally analyzed, and are interoperable across the biomedical research continuum. There is also an increasing need for methods to interrelate phenotypic data easily and accurately from experiments in animal models with human development and disease. RESULTS: Here we present the Xenopus phenotype ontology (XPO) to annotate phenotypic data from experiments in Xenopus, one of the major vertebrate model organisms used to study gene function in development and disease. The XPO implements design patterns from the Unified Phenotype Ontology (uPheno), and the principles outlined by the Open Biological and Biomedical Ontologies (OBO Foundry) to maximize interoperability with other species and facilitate ongoing ontology management. Constructed in Web Ontology Language (OWL) the XPO combines the existing uPheno library of ontology design patterns with additional terms from the Xenopus Anatomy Ontology (XAO), the Phenotype and Trait Ontology (PATO) and the Gene Ontology (GO). The integration of these different ontologies into the XPO enables rich phenotypic curation, whilst the uPheno bridging axioms allows phenotypic data from Xenopus experiments to be related to phenotype data from other model organisms and human disease. Moreover, the simple post-composed uPheno design patterns facilitate ongoing XPO development as the generation of new terms and classes of terms can be substantially automated. CONCLUSIONS: The XPO serves as an example of current best practices to help overcome many of the inherent challenges in harmonizing phenotype data between different species. The XPO currently consists of approximately 22,000 terms and is being used to curate phenotypes by Xenbase, the Xenopus Model Organism Knowledgebase, forming a standardized corpus of genotype-phenotype data that can be directly related to other uPheno compliant resources.

Phytochemicals-induced hormesis protects Caenorhabditis elegans against α-synuclein protein aggregation and stress through modulating HSF-1 and SKN-1/Nrf2 signaling pathways.

Mild stress activates the adaptive cellular response for the subsequent severe stress called hormesis. Hormetic stress plays a vital role to activate multiple stress-responsive genes for the benefit of an organism. In tropical regions of world, tubers of Dioscorea spp. has been extensively used in folk medicine and also consumed as food. In this study, we report that the phytochemicals of Dioscorea alata L., tubers extends the lifespan of nematode model Caenorhabditis elegans by hormetic mechanism. We showed that the low dose of tubers extract at 200 and 300 µg/mL extends the mean lifespan of wild-type worms, whereas higher doses are found to be toxic. Supplementation of tubers extract slightly increased the intracellular ROS in second-day adult worms and it might activate the adaptive stress response, which protects the worms from oxidative and thermal stress. Transgenic reporter gene expression assay showed that extract treatment enhanced the expression of stress protective genes such as hsp-16.2, hsp-6, hsp-60 and gst-4. Further studies proved that the transcription factors HSF-1 and SKN-1/Nrf2 were implicated in hormetic stress response of the worms. Moreover, pretreatment of extract reduced the high glucose-mediated lipid accumulation by enhancing the expression of glyoxalase-1. It was also found that the aggregation of Parkinson's related protein α-synuclein reduced in the transgenic strain NL5901 and extended its lifespan. Finally, our results concluded that the presences of hormetic dietary phytochemicals in tubers might drive the stress response in C. elegans via HSF-1 and SKN-1/Nrf2 signaling pathways.