SINC-seq: correlation of transient gene expressions between nucleus and cytoplasm reflects single-cell physiology

We report a microfluidic system that physically separates nuclear RNA (nucRNA) and cytoplasmic RNA (cytRNA) from a single cell and enables single-cell integrated nucRNA and cytRNA-sequencing (SINC-seq). SINC-seq constructs two individual RNA-seq libraries, nucRNA and cytRNA, per cell, quantifies gene expression in the subcellular compartments, and combines them to create novel single-cell RNA-seq data. Leveraging SINC-seq, we discover distinct natures of correlation among cytRNA and nucRNA that reflect the transient physiological state of single cells. These data provide unique insights into the regulatory network of messenger RNA from the nucleus toward the cytoplasm at the single-cell level

Compte rendu de « Desrosières, Alain (2014), Prouver et gouverner. Une analyse politique des statistiques publiques »

Prouver et gouverner étudie le rôle des institutions, des conventions et des enjeux normatifs dans la construction d’indicateurs quantitatifs. Desrosières pense qu’on ne peut étudier le développement scientifique des statistiques sans prendre en compte le développement institutionnel – en particulier le rôle de l’État – dans la constitution de cette discipline

Extreme deformability of insect cell membranes is governed by phospholipid scrambling

昆虫の細胞は柔らかい！ --細胞膜を柔らかくするタンパク質を発見--. 京都大学プレスリリース. 2021-06-09.Organization of dynamic cellular structure is crucial for a variety of cellular functions. In this study, we report that Drosophila and Aedes have highly elastic cell membranes with extremely low membrane tension and high resistance to mechanical stress. In contrast to other eukaryotic cells, phospholipids are symmetrically distributed between the bilayer leaflets of the insect plasma membrane, where phospholipid scramblase (XKR) that disrupts the lipid asymmetry is constitutively active. We also demonstrate that XKR-facilitated phospholipid scrambling promotes the deformability of cell membranes by regulating both actin cortex dynamics and mechanical properties of the phospholipid bilayer. Moreover, XKR-mediated construction of elastic cell membranes is essential for hemocyte circulation in the Drosophila cardiovascular system. Deformation of mammalian cells is also enhanced by the expression of Aedes XKR, and thus phospholipid scrambling may contribute to formation of highly deformable cell membranes in a variety of living eukaryotic cells

Wide-range frequency selectivity in an acoustic sensor fabricated using a microbeam array with non-uniform thickness

In this study, we have demonstrated the fabrication of a microbeam array (MBA) with various thicknesses and investigated the suitability it for an acoustic sensor with wide-range frequency selectivity. For this, an MBA composed of 64 beams, with thicknesses varying from 2.99–142 µm, was fabricated by using single gray-scale lithography and a thick negative photoresist. The vibration of the beams in air was measured using a laser Doppler vibrometer; the resonant frequencies of the beams were measured to be from 11.5 to 290 kHz. Lastly, the frequency range of the MBA with non-uniform thickness was 10.9 times that of the MBA with uniform thickness

Measurement of local electric field in microdevices for low-voltage electroporation of adherent cells

In this study, we present the measurement of the local electric field in a microdevice designed for electroporation of adherent cells. The microdevice mainly consists of a coverslip that has a transparent conductive layer and an insulating layer. The insulating layer has small cylindrical holes that focus the field lines to reduce the voltage required for electroporation. We estimated the local electric field at the cells by analyzing the ionic current based on a simple equivalent circuit model and investigated the correlation between the field strength and the efficiency of electroporation. We prepared various designs with matrices of electrodes with diameters ranging from 5 to 10 μm and center-to-center distances between adjacent electrodes ranging from 20 to 75 μm to perform systematic and statistical investigations. Furthermore, we discussed the efficiency of the electrode design in terms of the degree of field focusing, the applicability of optical observations, and the probability of positioning cells on the electrodes

Different motilities of microtubules driven by kinesin-1 and kinesin-14 motors patterned on nanopillars

モータータンパク質は種類により協働性が異なることを発見 --分子を自在に並べる技術により生体分子モーターの協働性を計測--. 京都大学プレスリリース. 2020-01-23.How're your cells' motors running?. 京都大学プレスリリース. 2020-01-23.Kinesin is a motor protein that plays important roles in a variety of cellular functions. In vivo, multiple kinesin molecules are bound to cargo and work as a team to produce larger forces or higher speeds than a single kinesin. However, the coordination of kinesins remains poorly understood because of the experimental difficulty in controlling the number and arrangement of kinesins, which are considered to affect their coordination. Here, we report that both the number and spacing significantly influence the velocity of microtubules driven by nonprocessive kinesin-14 (Ncd), whereas neither the number nor the spacing changes the velocity in the case of highly processive kinesin-1. This result was realized by the optimum nanopatterning method of kinesins that enables immobilization of a single kinesin on a nanopillar. Our proposed method enables us to study the individual effects of the number and spacing of motors on the collective dynamics of multiple motors