Biology subjects

Kato, Y. S.

Publications and source records attributed to Kato, Y. S..

3 recordsLinked to original sources

bioRxiv2026

Intranuclear Quantum Sensing with Fluorescent Nanodiamond Enabled by Electron-Irradiation and Surface-Chemical Optimization for Microinjection

Fluorescent nanodiamonds (FNDs) containing nitrogen-vacancy (NV) centers are promising quantum sensors for intracellular measurements, yet nuclear applications remained out of reach because optically detected magnetic resonance (ODMR) signals are weak and capillary delivery is inefficient. This study addresses both constraints by optimizing the electron irradiation dose to balance NV creation and charge-state stability, and by grafting hyperbranched polyglycerol with terminal carboxyl groups (HPGCOOH) to suppress aggregation and prevent needle clogging. The optimized dose yields strong ODMR contrast while preserving fluorescence suitable for microscopy. HPGCOOH surfaces enable smooth and reproducible microinjection through fine capillaries. Using this strategy, the microinjection of ODMR-active FNDs into the nuclei of living COS7 cells is achieved, and clear intranuclear spectra comparable to cytoplasmic readouts are obtained. Furthermore, field-of-view temperature sensing across multiple cell nuclei is demonstrated, enabling quantitative and spatially resolved thermal mapping within the genomic environment. This methodology provides a practical route to nuclear quantum sensing and opens opportunities for nanoscale physicochemical measurements within the genomic environment.

biophysics↗

bioRxiv2022

Interneurons of fan-shaped body promote arousal in Drosophila

Sleep is required to maintain physiological functions and is widely conserved across species. To understand the sleep-regulatory mechanisms, sleep-regulating genes and neuronal circuits are studied in various animal species. In the sleep-regulatory neuronal circuits in Drosophila melanogaster, the dorsal fan-shaped body (dFB) is a major sleep-promoting region. However, other sleep-regulating neuronal circuits were not well identified. We recently found a novel sleep-regulatory circuit consisting of arousal-promoting T1 dopamine neurons and protocerebral bridge (PB) neurons innervating the ventral part of the FB, which we named "the PB-FB pathway". However, the post-synaptic target of the PB-FB pathway was still unknown. To identify it, we performed anterograde tracing, immunohistochemistry, and Ca2+ imaging analysis and found that the PB-FB pathway projects to FB interneurons, also known as pontine neurons. Besides, we found that cholinergic pontine neurons promote arousal. Moreover, we indicated that pontine neurons form an anatomical connection with sleep-promoting dFB neurons. Together, we showed that pontine neurons receive excitatory signals from the PB-FB pathway and cholinergic pontine neurons promote arousal. These results completed one of the output pathways from the PB-FB pathway.

neuroscience↗

bioRxiv2020

Protocerebral bridge neurons that regulate sleep in Drosophila melanogaster

The central complex is one of the major brain regions that control sleep in Drosophila, but the circuitry details of sleep regulation have yet to be elucidated. Here, we show a novel sleep-regulating neuronal circuit in the protocerebral bridge (PB) of the central complex. Activation of the PB interneurons labeled by the R59E08-Gal4 and the PB columnar neurons in the R52B10-Gal4 promoted sleep and wakefulness, respectively. A targeted GFP reconstitution across synaptic partners (t-GRASP) analysis demonstrated synaptic contacts between these two groups of sleep-regulating PB neurons. Furthermore, we found that activation of a pair of dopaminergic (DA) neurons projecting to the PB (T1 DA neurons) decreased sleep. The wake-promoting T1 DA neurons and the sleep-promoting PB interneurons formed close associations. Dopamine 2-like receptor (Dop2R) knockdown in the sleep-promoting PB interneurons increased sleep. These results indicated that the neuronal circuit in the PB regulated by dopamine signaling mediates sleep-wakefulness.

neuroscience↗