Search

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]

We report a novel mathematical model of an artificial auditory system consisting of a micro‐machined cochlea and the auditory nerve response it evokes. The modeled micro‐machined cochlea is one previously realized experimentally by mimicking functions of the cochlea [Shintaku et al, Sens. Actuat. 158 (2010) 183–192; Inaoka et al, Proc. Natl. Acad. Sci. USA 108 (2011) 18390–18395]. First, from the viewpoint of mechanical engineering, the frequency characteristics of a model device were experimentally investigated to develop an artificial basilar membrane based on a spring–mass–damper system. In addition, a nonlinear feedback controller mimicking the function of the outer hair cells was incorporated in this experimental system. That is, the developed device reproduces the proportional relationship between the oscillation amplitude of the basilar membrane and the cube root of the sound pressure observed in the mammalian auditory system, which is what enables it to have a wide dynamic range, and the characteristics of the control performance were evaluated numerically and experimentally. Furthermore, the stimulation of the auditory nerve by the micro‐machined cochlea was investigated using the present mathematical model, and the simulation results were compared with our previous experimental results from animal testing [Shintaku et al, J. Biomech. Sci. Eng. 8 (2013) 198–208]. The simulation results were found to be in reasonably good agreement with those from the previous animal test; namely, there exists a threshold at which the excitation of the nerve starts and a saturation value for the firing rate under a large input. The proposed numerical model was able to qualitatively reproduce the results of the animal test with the micro‐machined cochlea and is thus expected to guide the evaluation of micro‐machined cochleae for future animal experiments. [ABSTRACT FROM AUTHOR]