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The molecular system regulating cellular mechanical properties remains unexplored at single-cell resolution mainly due to a limited ability to combine mechanophenotyping with unbiased transcriptional screening. Here, we describe an electroporation-based lipid-bilayer assay for cell surface tension and transcriptomics (ELASTomics), a method in which oligonucleotide-labelled macromolecules are imported into cells via nanopore electroporation to assess the mechanical state of the cell surface and are enumerated by sequencing. ELASTomics can be readily integrated with existing single-cell sequencing approaches and enables the joint study of cell surface mechanics and underlying transcriptional regulation at an unprecedented resolution. We validate ELASTomics via analysis of cancer cell lines from various malignancies and show that the method can accurately identify cell types and assess cell surface tension. ELASTomics enables exploration of the relationships between cell surface tension, surface proteins, and transcripts along cell lineages differentiating from the haematopoietic progenitor cells of mice. We study the surface mechanics of cellular senescence and demonstrate that RRAD regulates cell surface tension in senescent TIG-1 cells. ELASTomics provides a unique opportunity to profile the mechanical and molecular phenotypes of single cells and can dissect the interplay among these in a range of biological contexts. The molecular system regulating cell surface mechanics remains largely unexplored at single-cell resolution. Here, the authors report a high-throughput single-cell assay, ELASTomics, which integrates mechanical phenotyping with unbiased transcriptomics. [ABSTRACT FROM AUTHOR]

Summary: The pine wood nematode, Bursaphelenchus xylophilus , is the cause of pine wilt disease and reproduces by copulation within host pine trees. Female mate selection in B. xylophilus mating behaviour has been reported but definitive evidence is lacking. Furthermore, while the mating behaviour of the free-living nematode Caenorhabditis elegans on agar has been well understood, the mating behaviour of B. xylophilus on agar has not been studied in detail, and the differences in their characteristics remain unclear. Here, we addressed these knowledge gaps by observing B. xylophilus mating behaviour on agar. We identified six primary mating sub-behaviours in B. xylophilus males. Comparative analysis with C. elegans revealed distinct differences in the sequence of mating stages. Notably, B. xylophilus males actively searched for the female's vulva during the wrapping stage, whereas females exhibited back-and-forth locomotion to align the male spicule with the vulva location. Additionally, we conducted mating assays using anaesthetised female nematodes to evaluate the female's role in the mating behaviours of B. xylophilus. The mating duration increased significantly when females were anaesthetised, and the probabilities of reaching the wrapping and vulva location stages were reduced. Therefore, B. xylophilus females actively cooperate in mating behaviours. Our findings highlight unique aspects of mating behaviours in B. xylophilus and provide insights concerning differences in mating behaviours between B. xylophilus and C. elegans. [ABSTRACT FROM AUTHOR]

Recently, single-molecule manipulation techniques in micro- and nanofluidic channels have attracted significant attention. To precisely control the transport velocity, the dynamics of the surrounding liquid must be understood in addition to the behavior of the target particles. Some unknowns about interactions between electrolyte ions and solvents remain to be clarified from a microscopic viewpoint. Herein, we propose a technique to generate a liquid flow driven by ion transport phenomena, the so-called electrohydrodynamic (EHD) flow, where electrolyte ions are dialyzed using a cation-exchange membrane. With this method, it is possible to apply an electric body force in liquids, which is different from electroosmotic flows that are limited to ion transport in electric double layers, and is expected to be a good candidate for detailed control of liquid flows in micro- and nanofluidic channels. To collect basic design data based on the knowledge of microscopic fluid dynamics of the present technique, a mathematical model of an EHD flow dragged by electrical carriers in an ionic current is developed and results are compared with experimental data. In our experiments, EHD flows are efficiently driven by applied electric fields in a cation dominant current. To induce such an EHD flow, the externally applied electric potential can be drastically reduced to 2.0 V in comparison with previous methods because we do not need an excessively high voltage to inject electrical charges into liquids. This method enables us to induce EHD flows in aqueous solutions and is expected to open the door to low-voltage driven liquid flow control. [ABSTRACT FROM AUTHOR]