Biology subjects

Niino, Y.

Publications and source records attributed to Niino, Y..

3 recordsLinked to original sources

bioRxiv2024

Comparison of monomeric variants of StayGold

StayGold is a bright and highly photostable fluorescent protein (FP) that forms an obligate dimer, thereby limiting its application as a soluble marker. On the basis of the structural information of this FP, we disrupted the dimerization to generate a monomeric variant, mStayGold, which inherits both the extremely high photostability and the high practical brightness of StayGold, for molecular fusion and membrane-targeting applications. Meanwhile, two other research groups have independently monomerized StayGold using different strategies. As a result, multiple StayGold monomers are currently available, creating confusion in the research community. In the present study, we investigated the three basic properties--photostability, brightness, and dispersibility--of these monomers by performing detailed side-by-side comparisons. This study highlights the difficulties of StayGold monomerization with emphasis on the tradeoff between photostability and brightness in FP technology.

bioengineering↗

bioRxiv2020

Spatio-temporal spawning patterns and early growth of Japanese sardine in the western North Pacific during the recent stock increase

Spatio-temporal patterns in spawning influence growth and survival by affecting the environment experienced by offspring during their early life stages. Therefore, identifying changes in spawning patterns can help researchers understand population dynamics and recruitment fluctuations. The Japanese sardine Sardinops melanostictus is a small pelagic fish that undergoes large stock fluctuations. Although spawning patterns are known to change spatially and temporally with stock abundance, little information is available on the processes underlying stock increases. This study aimed to describe changes in spawning pattern and early growth of Japanese sardine during the recent period of stock increase, and to clarify the effects of different spawning periods on offspring growth. We examined trends in egg abundance in the western North Pacific in 2004-2018 and analyzed hatch dates and growth trajectories by otolith microstructure analysis of juveniles from the Kuroshio-Oyashio transitional region (the species main nursery area). During the study period, the main spawning area shifted from the western to the eastern part of this region off Japan, and spawning in the eastern part roughly coincided with juvenile hatch dates. Hatch dates also shifted from mid-March at the earliest to February and early March from 2013 onwards. Although early-hatched cohorts (which originate offshore of eastern Japan) experienced slower initial growth, they likely played an important role in the recent stock increase. Successful recruitment of these cohorts may have been facilitated by factors such as early hatching and transport to the nursery, which reduces the frequency of predator encounters.

ecology↗

bioRxiv2018

In vitro characterization of the human segmentation clock

The vertebral column is characterized by the periodic arrangement of vertebrae along the anterior-posterior (AP) axis. This segmental or metameric organization is established early in embryogenesis when pairs of embryonic segments called somites are rhythmically produced by the presomitic mesoderm (PSM). The tempo of somite formation is controlled by a molecular oscillator known as the segmentation clock 1,2. While this oscillator has been well characterized in model organisms 1,2, whether a similar oscillator exists in humans remains unknown. We have previously shown that human embryonic stem (ES) cells or induced pluripotent stem (iPS) cells can differentiate in vitro into PSM upon activation of the Wnt signaling pathway combined with BMP inhibition3. Here, we show that these human PSM cells exhibit Notch and YAP-dependent oscillations4 of the cyclic gene HES7 with a 5-hour period. Single cell RNA-sequencing comparison of the differentiating iPS cells with mouse PSM reveals that human PSM cells follow a similar differentiation path and exhibit a remarkably coordinated differentiation sequence. We also demonstrate that FGF signaling controls the phase and period of the oscillator. This contrasts with classical segmentation models such as the \"Clock and Wavefront\" 1,2,5, where FGF merely implements a signaling threshold specifying where oscillations stop. Overall, our work identifying the human segmentation clock represents an important breakthrough for human developmental biology.

developmental biology↗