Senkei Umehara's profile

What I do

A native Tokyoite acting as:

1) A first-year postdoc developing a nanosurgical tool for analyzing and controlling individual live cells; 90% effort.
2) A potential job-seeker in academia or editorial fields, or both; 10%.
3) A dream chaser hoping to catalyze reactions between Japanese science communities and those in the rest of the world; 4%.
4) A licensed tour guide for Japan, and a cultural ambassador residing in US Silicon Valley; 1%.
5) A hard-worker doing a little bit too much; 105% in total.

Affiliations

Current

Past

Location

City:
Santa Cruz, California, United States
Hub:
San Francisco Bay Area

Interests

As a scientist, I’m a man of curiosity who loves multidisciplinary approaches. The central topics would always, however, be fundamental issues in life sciences (e.g. life and death, hierarchical structures seen in nature, population vs. individuals, continuity vs. discreteness). Enjoying those intellectual challenges, I hope to ultimately contribute to biomedicine in a long run.

In my private life, I like playing golf and tennis, discovering neighborhoods, and learning foreign languages (ideally 10-20 only to say hello).

Projects

Current: Developing a nanopipette-based electrical biosensor/nanoinjector.
Extrapolating the idea of patch clamp electrodes, I am trying to build their nanoscale counterpart. A nanopipette I use has an approx. 50-nm pore in diameter at the tip, and potentially is capable of detecting (single) molecules without prior labeling and of injecting materials directly into a particular cell. It shares some important physical properties with nanopores but is unique in that it can be used for live cell analysis in real time.

Past: Studied how individual bacterial cells, Escherichia coli, respond to environmental perturbations.
The target cell was cultured in a microstructure and continuously monitored with a high-magnification microscope equipped with optical tweezers, thereby the cell was kept isolated from its “sisters” produced by binary fission while it remained in the same culture condition. I compared the growth curves and motility behavior of a mother and its daughter (well, they’re identical at the same time) to speculate what kind of information can be heritable without altering the genome at a single-cell level, without interacting with other cells around.

Publications

  • UMEHARA S, HATTORI A, INOUE I, YASUDA K. Asynchrony in the growth and motility responses to environmental changes by individual bacterial cells Biochemical and Biophysical Research Communications 356 (2) , 464 - 469 doi: 10.1016/j.bbrc.2007.03.001

  • Umehara S, Pourmand N, Webb C, Davis R, Yasuda K, Karhanek M. Current rectification with poly-l-lysine-coated quartz nanopipettes. Nano letters 6 (11) , 2486-92 PubMed ID:(17090078)

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