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Biology subjects

Shintani, M.

Publications and source records attributed to Shintani, M..

5 recordsLinked to original sources

Supporting Metadata Curation from Public Life Science Databases Using Open-Weight Large Language Models

Although the Gene Expression Omnibus and other public repositories are expanding rapidly, curation across these databases has not kept pace. Data reuse is often hindered by unstandardized metadata comprising unstructured text. To address this, we developed a workflow that combines retrieval via application programming interfaces with semantic filtering using large language models (LLMs) to support metadata screening as an initial step in broader curation workflows. As a focused pilot evaluation, we benchmarked multiple LLMs using metadata from 150 candidate Arabidopsis RNA-seq projects to classify projects containing exogenous ABA-treated samples and matched untreated controls. Simple keyword searches yielded many false positives (F1=0.59); classification using LLMs significantly improved performance. Several open-weight models achieved near-perfect classification performance in this defined task (F1>0.98), comparable to that of closed models. We also found that, for some high-performing models, self-reported confidence scores may help identify high-confidence cases that can be prioritized for automated processing. These results suggest that open-weight LLMs can support scalable metadata screening in local environments as an initial step in broader curation workflows, providing a foundation for accelerating public dataset reuse.

bioinformatics↗

INCOMPATIBILITY GROUPS OF PSEUDOMONAS PLASMIDS REVISITED: COMPREHENSIVE ANALYSIS OF R-FACTORS AND THEIR REPLICONS

Plasmids are the most influential engines of bacterial evolution and horizontal gene transfer, fueling the global spread of traits such as antimicrobial resistance. Their deep evolutionary relationships, however, remain difficult to resolve because current classification schemes are constrained by host range and nucleotide similarity. Replication initiation proteins (RIPs), which govern plasmid persistence and diversification, also remain poorly annotated across public databases. Here we establish PInc, a curated and experimentally grounded replicon classification framework anchored in historically defined incompatibility groups of Pseudomonas plasmids. Homology searches beyond PInc revealed that most replication initiators analyzed here share a conserved winged-helix (WH) domain, defining a broad WH RIP superfamily. Using the conserved WH region, we reconstructed a large-scale phylogeny that linked WH RIPs to over 100,000 plasmids, representing approximately half of those analyzed across public databases. This phylogeny resolved eight major clades and the deep split between the single- and double-winged-helix superclades, while revealing clade-specific host and environmental distributions and substantial RIP diversity not captured by current typing tools or annotation schemes. Together, these results overcome the historical host bias of plasmid typing and provide a replication-centered view of plasmid diversification across bacterial lineages and environments.

microbiology↗

Meta-analysis of public RNA-sequencing data of drought and salt stresses in different phenotypes of Oryza sativa

Environmental stresses, such as drought and salt, adversely affect plant growth and crop productivity. While many studies have focused on established components of stress signaling pathways, research on unknown elements remains limited. In this study, we collected RNA sequencing (RNA-Seq) data from Oryza sativa registered in public databases and conducted a meta-analysis integrating multiple studies. We analyzed 105 paired RNA-Seq datasets from resistant or susceptible Oryza sativa cultivars under salt and drought conditions to identify novel stress-responsive genes with common expression changes across these datasets. A meta-analysis identified 10 genes specifically upregulated in resistant cultivars and 12 specifically upregulated in susceptible cultivars under both drought and salt conditions. Furthermore, by comparing previously identified stress-responsive genes in Arabidopsis thaliana, we explored genes potentially involved in stress response mechanisms that are conserved across plant species. The genes identified in this data-driven study may serve as targets for future research and genome editing.

plant biology↗

Meta-Analysis of Public RNA Sequencing Data of Abscisic Acid-Related Abiotic Stresses in Arabidopsis thaliana

Abiotic stresses such as drought, salinity, and cold negatively affect plant growth and crop productivity. Understanding the molecular mechanisms underlying plant responses to these stressors is essential for stress tolerance in crops. The plant hormone abscisic acid (ABA) is significantly increased upon abiotic stressors, inducing physiological responses to adapt to stress and regulate gene expression. Although many studies have examined the components of established stress signaling pathways, few have explored other unknown elements. This study aimed to identify novel stress-responsive genes in plants by performing a meta-analysis of public RNA sequencing (RNA-Seq) data on Arabidopsis thaliana, focusing on five ABA-related stress conditions (ABA, Salt, Dehydration, Osmotic, and Cold). The meta-analysis of 216 paired datasets from five stress conditions was conducted, and differentially expressed genes were identified by introducing a new metric, called TN (stress-treated (T) and non-treated (N))-score. We revealed that 14 genes were commonly upregulated and 8 genes were commonly downregulated across all five treatments, including some that were not previously associated with these stress responses. On the other hand, some genes regulated by salt, dehydration, and osmotic treatments were not regulated by exogenous ABA or cold stress, suggesting that they may be involved in the plant response to dehydration independent of ABA. Our meta-analysis revealed a list of candidate genes with unknown molecular mechanisms in ABA-dependent and ABA-independent stress responses. These genes could be valuable resources for selecting genome editing targets and potentially contribute to the discovery of novel stress tolerance mechanisms and pathways in plants.

plant biology↗

STREAMING-tag system reveals spatiotemporal relationships between transcriptional regulatory factors and transcriptional activity

Transcription is a dynamic process that stochastically switches between the ON and OFF states. To detect the dynamic relationship among protein clusters of RNA polymerase II (RNAPII) and coactivators, gene loci, and transcriptional activity, we inserted an MS2 repeat, a TetO repeat, and inteins with a selection marker just downstream of the transcription start site (TSS). By optimizing the individual elements, we have developed the Spliced TetO REpeAt, MS2 repeat, and INtein sandwiched reporter Gene tag (STREAMING-tag) system. Clusters of RNAPII and BRD4 were observed proximally to the TSS of Nanog when the gene was transcribed in mouse embryonic stem cells. In contrast, clusters of MED19 and MED22 Mediator subunits were constitutively located near the TSS. Thus, the STREAMING-tag system revealed the spatiotemporal relationships between transcriptional activity and protein clusters near the gene. This powerful tool is useful for quantitatively understanding dynamic transcriptional regulation in living cells.

molecular biology↗