Toward a Multi-Omics-Based Single-Cell Environmental Chemistry and Toxicology

Heterogeneous Single-Cell Distribution of Trace-Level Metal Mixtures in Tetrahymena thermophila Using Mass Cytometry

The uptake of heavy metals by unicellular organisms can lead to the bioaccumulation of these metals in higher organisms, detrimentally affecting organismal health and ultimately impacts the ecosystems. By studying the uptake and accumulation of heavy metals in unicellular organisms, we gain insights into potential risks associated with low-dose heavy metal exposure in aquatic environments. Thus, to investigate the accumulation characteristics of Mo, Ag, Cd, Sn, Sb, Hg, Tl, and Pb mixtures in single Tetrahymena thermophila cells, we developed a label-free approach for the simultaneous absolute quantification of multiple metals in a single cell using mass cytometry. Our results demonstrated the dynamic changes in metal concentrations in T. thermophila, and the competition between metals in uptake and excretory pathways resulted in heterogeneous accumulation and bioconcentration of these metals. Additionally, our findings revealed the limited capacity of T. thermophila to excrete Cd and Hg, suggesting a higher risk for T. thermophila cells when exposed to Cd and Hg over an extended period. Therefore, the current study provides valuable data for a more comprehensive understanding of the impact of low-dose heavy metals on aquatic ecosystems.

Cellular nucleus image-based smarter microscope system for single cell analysis

Cell imaging technology is undoubtedly a powerful tool for studying single-cell heterogeneity due to its non-invasive and visual advantages. It covers microscope hardware, software, and image analysis techniques, which are hindered by low throughput owing to abundant hands-on time and expertise. Herein, a cellular nucleus image-based smarter microscope system for single-cell analysis is reported to achieve high-throughput analysis and high-content detection of cells. By combining the hardware of an automatic fluorescence microscope and multi-object recognition/acquisition software, we have achieved more advanced process automation with the assistance of Robotic Process Automation (RPA), which realizes a high-throughput collection of single-cell images. Automated acquisition of single-cell images has benefits beyond ease and throughout and can lead to uniform standard and higher quality images. We further constructed a single-cell image database-based convolutional neural network (Efficient Convolutional Neural Network, E-CNN) exceeding 20618 single-cell nucleus images. Computational analysis of large and complex data sets enhances the content and efficiency of single-cell analysis with the assistance of Artificial Intelligence (AI), which breaks through the super-resolution microscope's hardware limitation, such as specialized light sources with specific wavelengths, advanced optical components, and high-performance graphics cards. Our system can identify single-cell nucleus images that cannot be artificially distinguished with an accuracy of 95.3%. Overall, we build an ordinary microscope into a high-throughput analysis and high-content smarter microscope system, making it a candidate tool for Imaging cytology.

20 years of polybrominated diphenyl ethers on toxicity assessments

Polybrominated diphenyl ethers (PBDEs) serve as brominated flame retardants which continue to receive considerable attention because of their persistence, bioaccumulation, and potential toxicity. Although PBDEs have been restricted and phased out, large amounts of commercial products containing PBDEs are still in use and discarded annually. Consequently, PBDEs added to products can be released into our surrounding environments, particularly in aquatic systems, thus posing great risks to human health. Many studies and reviews have described the possible toxic effects of PBDEs, while few studies have comprehensively summarized and analyzed the global trends of their toxicity assessment. Therefore, this study utilizes bibliometrics to evaluate the worldwide scientific output of PBDE toxicity and analyze the hotspots and future trends of this field. Firstly, the basic information including the most contributing countries/institutions, journals, co-citations, influential authors, and keywords involved in PBDE toxicity assessment will be visualized. Subsequently, the potential toxicity of PBDE exposure to diverse systems, such as endocrine, reproductive, neural, and gastrointestinal tract systems, and related toxic mechanisms will be discussed. Finally, we conclude this review by outlining the current challenges and future perspectives in environmentally relevant PBDE exposure, potential carriers for PBDE transport, the fate of PBDEs in the environment and human bodies, advanced stem cell-derived organoid models for toxicity assessment, and promising omics technologies for obtaining toxic mechanisms. This review is expected to offer systematical insights into PBDE toxicity assessments and facilitate the development of PBDE-based research.