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OptoBioTechnology Research Center

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Nagoya Institute of Technology

International Symposium on“Optobiotechnology”
5 (Tue.) – 6 (Wed.) February 2019at the conference hall (4th building), Nagoya Institute of Technology

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OptoBioTechnology Research Center
Nagoya Institute of Technology
Address│ OptoBioTechnology Research Center, Nagoya Institute of Technology
Showa-ku, Nagoya 466-8555, JapanNIT URL │ http://www.nitech.ac.jp

OptoBioTechnology Research Center, Nagoya Institute of Technology

International Symposium on “Optobiotechnology”
February 5 - 6，2019
Nagoya Institute of Technology (Nagoya, Japan)

Plenary Lecturers
Oded Béjà (Israel Institute of Technology, Israel)Peter Hegemann (Humboldt University, Germany)
Ryoichiro Kageyama (Kyoto University, Japan)
Osamu Nureki (The University of Tokyo, Japan)
Krzysztof Palczewski (University of California, Irvine, USA)
Yoshinori Shichida (Ritsumeikan University, Japan)

Invited Speakers
Takehisa Dewa (Nagoya Institute of Technology, Japan)
Akimasa Hirata (Nagoya Institute of Technology, Japan)
Kota Katayama (Nagoya Institute of Technology, Japan)
Masae Konno (Nagoya Institute of Technology, Japan)
Shuji Ogata (Nagoya Institute of Technology, Japan)
Tetsuo Soga (Nagoya Institute of Technology, Japan)
Satoshi P. Tsunoda (Nagoya Institute of Technology, Japan)
Daichi Yamada (Nagoya Institute of Technology, Japan)
Tatsuyuki Yoshii (Nagoya Institute of Technology, Japan)

Organizer
Hideki Kandori (Nagoya Institute of Technology, Japan)

Welcome address

Experimental life science combined with optotechnology
In August 2013, Nagoya Institute of Technology (NIT) established a new center named
OptoBioTechnology Research Center. The center sets the goal to create a new field of industry,based on the optical manipulation technologies in bioscience, as represented by optogenetics.
One of the most fast-growing techniques is now indispensable in the brain science, in which the
optogenetic control of neural activity elucidates the brain function at the molecular level, as
well as in the neural network systems. We elucidate the molecular mechanisms of energy
conversion between light and biomaterials, which is yet fully understood, by using advanced
analytical tools. The most promising seeds shall be identified through the basic research, andwe will grow them to contribute the society to improve the quality of life.
On behalf of OptoBioTechnology Research Center of NIT, I sincerely welcome all of you tothis International Symposium, which is the 5th Anniversary Memorial Symposium of the center.
I am pleased that outstanding researchers in the “Light & Life” field agreed to come and give
Plenary Lectures, which leads to the symposium success. You will also see the research
activities on “Light & Life” in NIT from invited talks and poster presentations.
I hope all the participants enjoy this symposium and get new inspirations.

Hideki KandoriCenter Director,
OptoBioTechnology Research Center,
Nagoya Institute of Technology

Member List, OptoBioTechnology Research Center

Optoscience Department
Yuji Furutani (Department of Life Science and Applied Chemistry, NIT)
Shuji Ogata (Department of Physical Science and Engineering, NIT)
Shingo Ono (Department of Physical Science and Engineering, NIT)
Norihiro Shida (Department of Life Science and Applied Chemistry, NIT)

Optoenergy Technology Department
Tomohiko Inomata (Department of Life Science and Applied Chemistry, NIT)
Hideki Kandori (Department of Life Science and Applied Chemistry, NIT)
Katsuhiko Ono (Department of Life Science and Applied Chemistry, NIT)
Tetsuo Soga (Department of Electrical and Mechanical Engineering, NIT)

Optomedical Technology Department
Takehisa Dewa (Department of Life Science and Applied Chemistry, NIT)
Akimasa Hirata (Department of Electrical and Mechanical Engineering, NIT)
Kota Katayama (Department of Life Science and Applied Chemistry, NIT)
Akiko Obata (Department of Life Science and Applied Chemistry, NIT)

Selected Publications and Awards, OptoBioTechnology Research Center
2014
O. P. Ernst, D. T. Lodowski, M. Elstner, P. Hegemann, L. S. Brown, H. Kandori,"Microbial and animal rhodopsins: Structures, functions, and molecular mechanisms"
Chem. Rev. 114, 126-163 (2014).
Comprehensive review article on rhodopsins; 395 citations (Dec. 27, 2018).
2015
H. E. Kato, K. Inoue, R. Abe-Yoshizumi, Y. Kato, H. Ono, M. Konno, S. Hososhima, T. Ishizuka,
M. R. Hoque, H. Kunitomo, J. Ito, S. Yoshizawa, K. Yamashita, M. Takemoto, T. Nishizawa, R.
Taniguchi, K. Kogure, A. D. Maturana, Y. Iino, H. Yawo, R. Ishitani, H. Kandori, O. Nureki,"Structural basis for Na+ transport mechanism by a light-driven Na+ pump"Nature 521, 48-53 (2015).
Structure/function study of Krokinobacter eikastus rhodopsin 2 (KR2).
Hideki Kandori, Molecular Science Society Award （分子科学会賞）
2016
M. Konno, Y. Kato, H. E. Kato, K. Inoue, O. Nureki, H. Kandori,"Mutant of a light-driven sodium ion pump can transport cesium ions"J. Phys. Chem. Lett. 7, 51-55 (2016).
Creation of Cs+ pump by light, which was reported by many newspapers.
K. Inoue, S. Ito, Y. Kato, Y. Nomura, M. Shibata, T. Uchihashi, S. P. Tsunoda, H. Kandori,"Natural light-driven inward proton pump"
Nat. Commun. 7, 13415 (2016).
Discovery and characterization of a light-driven inwardly-directed proton pump.
2017
S. Gulati, B. Jastrzebska, S. Banerjee, Á. L. Placeres, P. Miszta, S. Gao, K. Gunderson, G. P.
Tochtrop, S. Filipek, K. Katayama, P. D. Kiser, M. Mogi, P. L. Stewart, K. Palczewski,"Photocyclic behavior of rhodopsin induced by an atypical isomerization mechanism"
Proc. Natl. Acad. Sci. USA 114, E2608-E2615 (2017).
Dr. Katayama’s study in USA, whose manuscript was published after his return to Japan.

K. Katayama, Y. Nonaka, K. Tsutsui, H. Imai, H. Kandori,"Spectral tuning mechanism of primate blue-sensitive visual pigment elucidated by FTIR
spectroscopy"
Sci. Rep. 7, 4904-4914 (2017).
The first structural study of primate blue-sensitive protein, being reported by many newspapers.
Akimasa Hirata, JSPS Award & Japan Academy Medal（日本学術振興会賞＆日本学士院学
術奨励賞）

2018
A. Pushkarev, K. Inoue, S. Larom, J. Flores-Uribe, M. Singh, M. Konno, S. Tomida, S. Ito, R.
Nakamura, S. P. Tsunoda, A. Philosof, I. Sharon, N. Yutin, E. V. Koonin, H. Kandori, O. Béjà,"A distinct abundant group of microbial rhodopsins discovered using functional metagenomics"
Nature 558, 595-599 (2018).
Discovery of heliorhodopsin through the collaboration with an Israel group.
Y. S. Kim, H. E. Kato, K. Yamashita, S. Ito, K. Inoue, C. Ramakrishnan, L. E. Fenno, K. E.
Evans, J. M. Paggi, R. O. Dror, H. Kandori, B. K. Kobilka, K. Deisseroth,"Crystal structure of the natural anion-conducting channelrhodopsin GtACR1"Nature 561, 343-348 (2018).
H. E. Kato, Y. S. Kim, J. M. Paggi, K. E. Evans, W. E. Allen, C. Richardson, K. Inoue, S. Ito, C.
Ramakrishnan, L. E. Fenno, K. Yamashita, D. Hilger, S. Y. Lee, A. Berndt, K. Shen, H. Kandori,
R. O. Dror, B. K. Kobilka, K. Deisseroth,"Structural mechanisms of selectivity and gating in anion channelrhodopsins"
Nature 561, 349-354 (2018).
Spectroscopic contribution to the structural analysis by Stanford group.
H. Kandori, K. Inoue, S. P. Tsunoda,"Light-driven sodium-pumping rhodopsin: a new concept of active transport"
Chem. Rev. 118, 10646-10658(2018).
This protein can actively transport Na+ without initial binding, which is very unusual.
2019
Hideki Kandori, Chemical Society of Japan (CSJ) Award （日本化学会賞）

Program
Schedule and Oral Presentations
February 5 (Tue)8:50 Opening Remark: Hiroyuki Ukai (President; Nagoya Institute of Technology, Japan)
Session 1 Light & Life: Animal Rhodopsins
Chair: Yuji Furutani (Nagoya Institute of Technology, Japan)
9:00 Plenary Lecture: Krzysztof Palczewski (University of California, Irvine, USA)
“Chemistry that converts light into vision”
9:45 Plenary Lecture: Yoshinori Shichida (Ritsumeikan University, Japan)“Opsin evolution: Exploring the effects of mutations”
10:30 Invited Talk: Kota Katayama (Nagoya Institute of Technology, Japan)“Structural basis for elucidating spectral tuning mechanism of cone pigments”
Session 2 Light & Life: Microbial Rhodopsins
Chair: Shinya Tsukiji (Nagoya Institute of Technology, Japan)
11:00 Plenary Lecture: Oded Béjà (Israel Institute of Technology, Israel)“Type-1 & 3 rhodopsins: The search for new microbial rhodopsins using
metagenomics”
11:45 Plenary Lecture: Osamu Nureki (The University of Tokyo, Japan)“Light-gated opening mechanism of channelrhodopsin and structure-guided
development of optogenetics tools”
12:30 Invited Talk: Masae Konno (Nagoya Institute of Technology, Japan)“Molecular properties of new type microbial rhodopsins”
12:50-13:50 Lunch

Session 3 Light & Life: Optogenetics
Chair: Masahiko Hibi (Nagoya University, Japan)
13:50 Plenary Lecture: Peter Hegemann (Humboldt University, Germany)“Two component optogenetics”
14:35 Plenary Lecture: Ryoichiro Kageyama (Kyoto University, japan)“Oscillatory control of somitogenesis and neurogenesis: imaging and control ofgene expression by light technology”
15:20 Invited Talk: Satoshi P. Tsunoda (Nagoya Institute of Technology, Japan)“Enzyme rhodopsins, potential optogenetics tools for modulating intracellularcyclic-nucleotide levels”
15:40 Invited Talk: Daichi Yamada (Nagoya Institute of Technology, Japan)“FTIR study of photoactivated cyclase”
16:00 Invited Talk: Tatsuyuki Yoshii (Nagoya Institute of Technology, Japan)“Optochemical control of protein localization in living cells using syntheticorganic molecules”
Photograph
16:20-18:30 Poster Session
16:45-17:15 Odd numbers
17:30-18:00 Even numbers

19:00 Banquet
KOUYOUEN (Sapporo Nagoya Brewery) 浩養園 052-741-0211
http://www.kouyouen.jp/index.html

February 6 (Wed)Session 4 General Light & Life
Chair: Tomohiko Inomata (Nagoya Institute of Technology, Japan)
10:00 Invited Talk: Shuji Ogata (Nagoya Institute of Technology, Japan)“Exotic Behavior of Water Around the Anti-Freeze Protein: Large-Scale
Molecular Dynamics Simulations”
10:25 Invited Talk: Tetsuo Soga (Nagoya Institute of Technology, Japan)“Effect of third component in bulk-heterojunction organic solar cell”
10:50 Invited Talk: Takehisa Dewa (Nagoya Institute of Technology, Japan)“Functional Extension and Linkage of Photosynthetic BiohybridLight–Harvesting/Reaction Center Complexes in Artificial Systems”
11:15 Invited Talk: Akimasa Hirata (Nagoya Institute of Technology, Japan)“Multiscale modeling of electrostimulation”
11:40 Closing Remark: Hideki Kandori (Center Director; Nagoya Institute of Technology, Japan)

Poster Presentations
P01

Spectroscopic analysis of homo-oligomerization of AtCRY2
Kazuya Agata, Daichi Yamada, Hideki Kandori

P02

Characteristic of Dye Sensitized Solar Cell using PEDOT:PSS Counter Electrode on theTransparent Conductive Oxide
Masaya Ando, Yurie Murata, Shinya Kato, Naoki Kishi, Tetsuo Soga

P03

Molecular Dynamics Simulation of Water around Amino Acids of the Anti-freeze
proteinHayato Demura, Shuji Ogata, and Yasuhiro Kajima

P04

Infrared spectroscopy on membrane proteins for studying their molecular mechanisms
Yuji Furutani

P05

Characterization of high light-sensitive cation channels from Guillardia theta
Shoko Hososhima, Hideki Kandori, Satoshi Tsunoda

P06

Artificial Siderophore Fe Complexes-modified Substrates: Application to Microbial
Sensors and Reactors
Tomohiko INOMATA, Suguru ENDO, Hiroki IDO, Tomohiro OZAWA, and Hideki
MASUDA

P07

Three-dimensional mapping of Eu2+ ions and Eu3+ions doped CaF2 single crystal bymeasurement of multi-photon luminescence
Hiroaki Ito, Shusaku Terakawa, Toru Asaka, Akihiro Yamaji, Shunsuke Kurosawa,
Akira Yoshikawa, Shingo Ono

P08

Metal binding to the voltage-gated proton channel studied by ATR-FTIR spectroscopy
combined with MD/QC calculations
Masayo Iwaki, Kohei Takeshita , Hiroko X. Kondo, Kengo Kinoshita, Yasushi Okamura,Yu Takano, Atsushi Nakagawa and Hideki Kandori

P09

Fast Computation of Temperature and Water Loss in Human Models for Simultaneous
Exposure to Ambient Heat and Solar Radiation
T. Kamiya, K. Hasegawa, and A. Hirata

P10

Spectroscopic study of microbial rhodopsin with deprotonated retinal Schiff base atneutral pH
Chihiro Kataoka, Keiichi Inoue, Kota Katayama, Oded Béjà, Hideki Kandori

P11

Energy Transfer of LH2-Fluorophore Conjugates Using a Mutant of Light HarvestingComplex (LH2)
Daiji KATO, Akari GOTO, Masaharu KONDO, Yusuke YONEDA, Hiroshi
MIYASAKA, Yutaka NAGASAWA, Takehisa DEWA
P12Development of Vacuum Ultraviolet Light Detector Using Electric Property of
CaF2-metal Interface
Seiya Kato, Kentaro Suzuki, Jun Otani, Masahiko Kase, Shingo Ono

P13

Reconstitution of zinc protoporphyrin IX with transmembrane cytochrome b and its
photochemical functions
Hiroki Kojima, Yoko Kondo, Masaharu Kondo, Masaki Ihara, Takehisa Dewa

P14

Synthesis and Properties of N-Boc-Pyrrole Derivatives as p-Type Semiconductors
Takuya Matsuoka, Yuya Makino, Yuta Imaeda, and Katsuhiko Ono

P15

Molecular characterization of heliorhodopsins from marine giant virus
Ritsu Mizutori, Masae Konno, Keiichi Inoue, Oded Béjà, Hideki Kandori

P16

Synthesis and Absorption Properties of Bis(dioxaborin) Derivatives
Yoshitaka Mori, Fumiyasu Ishikawa, and Katsuhiko Ono

P17

Study on the regulatory mechanism of absorption-wavelength of rhodopsins andconstruction of red-shift mutants for optogenetics
Yuta Nakajima, Keiichi Inoue, Hideki Kandori

P18

Protein Adsorption Behaviors on Calcium-salt Particles
Chiaki Otsuka, Hirotaka Maeda, Akiko Obata, Toshihiro Kasuga

P19

Electrospun fibermats with protein-loading ability for tissue engineering
Y. Ozeki, M. Iguchi, T. Mizuno, A. Obata, T. Kasuga.

P20

Molar Concentration Precursors Effect on the Optical and Photovoltaic Properties of
BiOI Films Prepared by SILAR
Anissa A. Putri S. Kato, N. Kishi and T. Soga

P21

The correlation between the hydrogen bonding network and FAD redox states inphotolyase/cryptochrome family
Yui Sakai, Daichi Yamada, Hideki Kandori

P22

Synthesis and Absorption Properties of (1,3-Diketonato)boron Difluoride Derivatives
with π-Extended Triphenylamine
Yuki Sakura, Keisuke Banno, and Katsuhiko Ono

P23

FTIR study of primate green-sensitive cone visual pigment at >100 K

Takuma Sasaki, Kota Katayama, Rei Abe-Yoshizumi, Hiroo Imaiand Hideki Kandori
P24

Theoretical study of multiple proton transfer reaction in DNA base pair
Tsugutake Kato, Norihiro Shida

P25

Study of cation channelrhodopsin Gt_CCR4 for optogenetics
Shunta Shigemura, Shoko Hososhima, Hideki Kandori, Satoshi Tsunoda

P26

Identification of Novel Family in Microbial Rhodopsin: Heliorhodopsin (HeR) and
Mutational Analysis of Heliorhodopsin 48C12
Manish Singh, Keiichi Inoue, Alina Pushkarev, Akihiro Otomo, Yasuhisa Mizutani,
Oded Béjà, and Hideki Kandori

P27

Evaluation of cell penetration properties of the series of cationic PG-surfactants
Natsumi Sumito

P28

3D flexible processing of organic materials by femtosecond laser
Yoshiki Tanaka, Fumihiro Itoigawa, Hironori Suzuki, Hiroshi Nakao, Shingo Ono

P29

Unique channel kinetics of anion channelrhodopsin GtACR1
Rintaro Tashiro, Hideki Kandori, Satoshi Tsunoda

P30

The evaluation of Ce3+ ion distribution in Ce3+:LiCaAlF6 single crystal by multiphoton
luminescence and the effect on lasing properties
Shusaku Terakawa, Hiroaki Ito, Marilou Cadatal-Raduban, Takafumi Hirata, Shingo
Ono

P31

FTIR analysis of hydrogen bonding network in the extracellular side of a light-driven
sodium pump KR2
Sahoko Tomida, Shota Ito, Keiichi Inoue, Hideki Kandori

P32

Photoreaction Mechanism of Enzymatic Rhodopsin Rh-PDE revealed by Infrared
Spectroscopy
Masahito Watari, Tatsuya Ikuta, Daichi yamada, Wataru Shihoya, Kazuho Yoshida,
Satoshi Tsunoda, Osamu Nureki, Hideki Kandori

P33

Gaining function of microbial rhodopsin without retinal-binding lysine
Yumeka Yamauchi, Masae Konno, Daichi Yamada, Kei Yura, Keiichi Inoue, Oded Béjà
and Hideki Kandori

P34

Terahertz Antireflective Tapered Structures Fabricated by Femtosecond Laser
Processing
Xi Yu, Seiya Kato, Michiharu Onta, Bae Jongsuck, Shingo Ono

P35

Boron β-Ketoiminate Dye Sensitizers Containing Linear D-π-A Structures
Fumina Yumioka and Katsuhiko Ono

P36

Silver-doped bioactive glasses with cotton-wool-structure for wound dressing
T. Zenji, E. Norris, G. Poologasundarampillai, J R. Jones, A. Obata, T. Kasuga

Oral Presentation

Session 1 : Light & Life; Animal rhodopsins #1

Chemistry that Converts Light into Vision
Krzysztof Palczewski
Center for Translational Vision Research; Gavin Herbert Eye InstituteDepartment of Ophthalmology, University of California, Irvine, CA 92697-4375
The retina converts light into an electrical signal through a series of biochemical steps
collectively referred to as phototransduction. This signal is eventually relayed to the visualcortex of the brain, where visual perception occurs. Photoreceptor cells are able to respond tolight throughout our lives because they have the ability to regenerate proteins as well as a lightsensitive chromophore. The long-term objective of our research is to elucidate the molecular
reactions involved in phototransduction, including those directly involved in the regenerative
capability of photoreceptor cells. Phototransduction serves as a prototype for a multitude of G
protein-mediated signal transduction events initiated by activation of G protein-coupled
receptors (GPCRs) and thus understanding of this process is broadly applicable to other signaltransduction cascades. Although outnumbered more than 20:1 by rod photoreceptors, cone cells
in the human retina mediate daylight vision and are critical for visual acuity and color
discrimination. Originating in the early 1900s, past research has begun to provide insights into
cone ultrastructure but has yet to afford an overall perspective of cone cell organization.
Mutations in the rod and cone genes encoding are among the main causes of blinding diseases
in humans. We ultimate goal to advance our understanding of the molecular basis of vision andto develop strategies to stop progression of human retinal diseases using animal models.
Pharmacologic interventions to save vision are now within reach due to a significantly improved
understanding of these chemical transformations.

Session 1 : Light & Life; Animal rhodopsins #2

Opsin evolution: Exploring the effects of mutations
Yoshinori Shichida
Research Organization for Science and Technology,
Ritsumeikan University, Kusatsu, Shiga 525-8577, JAPANVison plays a very important role in our daily life and a considerable part of our brain is utilized
for visual information processing. Animals evolved from simple forms, and our visual function is
also the product of countless iterations resulting in a highly complex system. Visual function
probably first emerged from an ancestral G protein-coupled receptor which used a molecule(retinal) that can absorb light as a ligand. The original agonist was probably all-trans-retinal
which can undergo an isomerization reaction by light and would change the receptor into a low
activity state. Then the receptor evolved so that the isomerized retinal molecule can function as
an inverse agonist. Finally, the receptor may have evolved to preferentially bind to the inverse
agonist. Now a days, with the excellence of light as an information medium, the opsin receptor
has diversified tremendously, supporting light receiving functions of most animals.
Unlike the eyes of insects and molluscs (squid and octopus), vertebrate eyes are thought to beorgans that originally only perceived light and darkness, such as the circadian rhythm, rather thanorgans that mediated vision. They evolved into elaborative visual organs during the transition
from protochordates to vertebrates, and further evolved into the eyes of primates including
humans through the nocturnal evolutionary period of mammals. What kind of changes happened
to opsins during these processes, and what kind of visual functions were induced by the changes
in opsins?
Evolution and diversification of opsin can be thought as mutational experiments conducted by
Nature. Using recent genetic engineering techniques, it is possible to reproduce opsin changes in
the laboratory and to estimate how the opsin's molecular properties changed during evolution.
Additionally, it may be possible to create opsins with molecular properties consistent with our
specific purpose based on opsin evolution. In this talk, I will outline the mutational experiments
we are doing from the viewpoint of opsin evolution and review the evolution toward human eyes.

Session 1 : Light & Life; Animal rhodopsins #3

Structural basis for elucidating spectral tuning mechanism of cone
pigments
Kota Katayama
Department of Life Science and Applied Chemistry, Nagoya Institute ofTechnology
OptoBio Technology Research Center, Nagoya Institute of Technology
Vitamin A is adequately distributed within the body to maintain the biological function ofretinoids in the peropheral tissues and the production of visual chromophore, 11-cis-retinal, in theeye. One of the mysteries in our vision is that humans recognize color by use of a single
chromophore molecule (11-cis-retinal), meaning that the chromophore is identical even between
blue-absorbing and red-absorbing sensors. Thus, 11-cis-retinal is versatile photo-sensitive nanomachine in the eye. Humans have two different types of retinal containing light-sensitive proteins
expressed in the retina, rhodopsin (Rh) achieving twilight vision and three cone pigments, whichmediate color vision. Each different chromophore-protein interaction allows preferential
absorption of selected range of wavelengths. While the structural basis for photoreaction andsignal transduction of Rh has been well understood by determination of its atomic revel structure,
structural studies of cone pigments lag far behind those of Rh, mainly because of difficulty insample preparation and lack of suitable methods in structural analysis.
We thus attempted to express monkey cone pigments in HEK293 cell lines for structural
analysis using light-induced difference Fourier-transform infrared (FTIR) spectroscopy at 77K.
The first structural information successfully elicited from the highly accurate spectra for eachcone pigment showed that the retinal chromophore is structurally similar between Rh and cone
pigments, but hydrogen-bonding network around the retinal chromophore is entirely different
between them. In addition, some spectral differences are observed between cone pigments,
including protein-bound water molecules.

These differences could be interpreted to play a rolein spectral tuning.
Structural determination of cone pigments is also needed for a precise understanding ofspectral tuning. The principle obstacle to solving the structures is their innate instability indetergent micelles. Here, we demonstrate successful optimization for the expression by insect
cells (Sf9), purification, and stabilization with thermally stable site-directed mutation of primate
cone pigments for further structural determinations.

Session 2 : Light & Life; Microbial rhodopsins #1

Type-1 & 3 rhodopsins:
The search for new microbial rhodopsins using metagenomics
Oded Béjà1, Johannes Oppermann2, Jonas Wietek2, Peter Hegemann2, Keiichi
Inoue3, Hideki Kandori3,4
1Faculty of Biology, Technion – Israel Institute of Technology, Haifa, Israel;
2Institute for Biology, Experimental Biophysics, Humboldt-Universität zu Berlin,
Berlin, Germany; 3Department of Life Science and Applied Chemistry, Nagoya
Institute of Technology, Nagoya, Japan; 4OptoBioTechnology Research Center,
Nagoya Institute of Technology, Nagoya, Japan
Many organisms capture or sense sunlight using rhodopsin pigments. These rhodopsins are
currently divided to two distinct protein families: type-1 (microbial rhodopsins) and type-2(animal rhodopsins). Type-1 and type-2 rhodopsins show little or no sequence similarity to eachother, as a consequence of extensive divergence from a common ancestor or convergent
evolution of similar structures. Searching metagenomes from the Tara Oceans expedition, newanion channelrhodopsins (type-1) were detected that form a distinct family compared to the 3
known cation and anion channelrhodopsin families. The novel rhodopsins show anunprecedented desensitization of the initial peak current to almost zero activity in continuous
light. In addition, and this time using functional metagenomics, a previously unknown diverse
family, heliorhodopsins (type-3), which are distantly related to type-1 rhodopsins was
discovered. The orientation of heliorhodopsins in the membrane is opposite to that of type-1 ortype-2 rhodopsins, with the N-terminus facing the cell cytoplasm. In addition, heliorhodopsinsshow photocycles longer than 1 second, suggestive of light sensory activity. In my lecture I will
discuss the potential of metagenomics for future discoveries of new rhodopsin activities.

Session 2 : Light & Life; Microbial rhodopsins #2

Molecular mechanism of channelrhodopsin and structure-guided
development of useful optogenetics tools
Osamu Nureki
Department of Biological Sciences, Graduate School of Science, The Universityof Tokyo, 2-11-16 Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
Abstract
Channelrhodopsins (ChRs) are light-activated cation channels that mediate cation permeation
across the cell membrane upon light perception. We first solved the high-resolution crystal
structure of ChR (C1C2), and based on the structure, many ChR variants are made and utilized in
optogenetics. We designed by QM/MM simulation and developed blue-shifted variant. Amongthese variants, red-shifted (650 nm) channelrhodopsins are particular important, because thelonger wavelength light allows penetration into deeper tissues. However, the molecularmechanism of the red-shifted absorption has not been elucidated so far. Here we report the crystal
structure of the most red-shifted channelrhodopsin, Chrimson, at 2.6 Å resolution. The structure
revealed unique molecular architectures to achieve its highly red-shifted absorbance;hydrophobicity around the retinal Schiff’s base and the biased distribution of the polar residues
and the rigidity in the retinal binding pocket. The structural comparison revealed that Chrimson
has several structural features that resemble the light-activated proton pump, bacteriorhodopsin,
while retaining the similarity to other channelrhodopsins around the ion channel pore, indicatingthat Crimson is a primitive variant during molecular evolution from the prokaryotic ancestors.
Based on these mechanistic insights, we engineered ChrimsonSA, a mutant with an about 20 nm
red-shifted maximum activation wavelength and accelerated closing kinetics. When expressed in
hippocampal neurons, ChrimsonSA allowed selective action potential generation with red light,
and thus it is ideally suited for dual color optogenetic applications. To uncover the mechanism
how ChR opens the channel upon perception of blue light, we performed time-resolved
crystallography using XFEL in SACLA. I will talk about the light activation mechanism of ChR.
References
1. “Crystal structure of the red light-activated channelrhodopsin Chrimson” K. Oda, J. Vierock,
S. Oishi, S. Rodriguez-Rozada, R. Taniguchi, K. Yamashita, J. S. Wiegert, T. Nishizawa, P.
Hegemann and O. Nureki.
Nat. Commun. in press.

2. “Atomistic design of microbial opsin-based blue-shifted optogenetics tools”H. E. Kato, M.
Kamiya, S. Sugo, J. Ito, R. Taniguchi, A. Orito, K. Hirata, A. Inutsuka, A. Yamanaka, A. D.
Maturana, R. Ishitani, Y. Sudo, S. Hayashi and O. Nureki.
Nat. Commun. 6, 7177 (2015). doi: 10.1038/ncomms8177.
3. H. E. Kato, K. Inoue, R. Abe-Yoshizumi, Y. Kato, H. Ono, M. Konno, T. Ishizuka, M. R.
Hoque, S. Hososhima, H. Kunitomo, J. Ito, S. Yoshizawa, K. Yamashita, M. Takemoto, T.
Nishizawa, R. Taniguchi, K. Kogure, A. D. Maturana, Y. Iino, H. Yawo, R. Ishitani, H.
Kandori and O. Nureki “Structural basis for Na+ transport mechanism by a light-driven Na+
pump”
Nature 521, 48-53 (2015) DOI 10.1038/nature14322.
4. “H. E. Kato, F. Zhang, O. Yizhar, C. Ramakrishnan, T. Nishizawa, K. Hirata, J. Ito, Y. Aita,
T. Tsukazaki, S. Hayashi, P. Hegemann, A. D. Maturana, R. Ishitani, K. Deisseroth and O.
Nureki “Crystal structure of the channelrhodopsin light-gated cation channel”
Nature 482, 369-374 (2012).

Session 2 : Light & Life; Microbial rhodopsins #3

Molecular properties of new type microbial rhodopsins
Masae Konno(1Grad. Sch. Eng., NIT, 2OBTRC, NIT)
Microbial rhodopsin is the photoreceptive membrane protein which binds an all-trans retinal
as a chromophore to a conserved Lys residue. Microbial rhodopsins show various functions uponretinal photoisomerization, such as light-driven ion transporter, light sensor and light-activatedenzyme. Here, our recent studies on new types of rhodopsins will be presented.
Heliorhodopsins (HeRs) were found by functional metagenomic analysis1. Their amino-acidsequences are far different from typical microbial rhodopsins. We investigated molecularproperties of 48C12, the first-discovered HeR, by biophysical methods. While 48C12 showed no
ion transport activity, a long photocycle with multiple-proton transfer processes was observed
suggesting that 48C12 works as a light-sensor. The laser flash photolysis with a pH-indicator and
FTIR spectroscopy provided more insights about the proton transfer process related to M-state.
Schizorhodopsins (SzRs) were discovered from Asgardaeota archaea which is the closest
extant relative of eukaryotes to date and metagenomic scaffolds from putative bacteria. Multiple
sequence alignments showed that SzRs is present at the phylogenetically intermediate position
between type-1 rhodopsins and HeRs. Upon light-illumination SzRs showed a strong inward
proton-pumping activity. To reveal the mechanism of inward proton-transport, we conducted sitedirected mutational analysis of one of SzRs, AM_5S_00009. Some of the mutants for the residues
expected to be located on the proton transport pathway abolished proton transport activities.
Based on these results, we will discuss the mechanism of active inward proton-transport.
Although the conserved Lys residue is considered to be essential for the rhodopsin function,
many rhodopsin-like proteins without conserved Lys residue (Rh-noK) are present in nature. The
presence of Rh-noK suggests that it has some physiological role. Recently, we succeed in afunctional recovery of Rh-noK using site-directed mutagenesis. E. coli cells expressing
SAMEA2621536_1986778_5.1 (SAMEA5.1) Rh-noK exhibited no color, because of no retinal
binding. When retinal-binding Lys was introduced to the corresponding position of SAMEA5.1,
the cells showed a visible color. Additional mutation of the Schiff base counterion site conferreda proton pumping activity. Success of gaining function, the visible color and proton pumping
activity, suggests that Rh-noK conserves a characteristic structure of microbial rhodopsins.
1. A. Pushkarev, K. Inoue, S. Larom, J. Flores-Uribe, M. Singh, M. Konno, S. Tomida, S. Ito, R. Nakamura,
S. P. Tsunoda, A. Philosof, I. Sharon, N. Yutin, E. V. Koonin, H. Kandori*, O. Béjà*. “A Distinct AbundantGroup of Microbial Rhodopsins Discovered via Functional Metagenomics” Nature (2018) 558, 595-599.

Session 3 : Light & Life; Optogenetics #1

Two component optogenetics
Peter Hegemann, Ulrike Scheib, Matthias Broser, Yinth Andrea Bernal Sierra
Humboldt-Universität zu Berlin, Germany
The recently discovered photoreceptor family of enzyme rhodopsins comprises a number of
Rhodopsin-cyclases (RhGC/ACs) and Rhodopsin-phosphodiesterases (RhPDEs). These arerhodopsins that are either directly connected to an enzyme as realized in fungal class ofBlasticladiomycetes (Avelar et al. 2014 Curr.Biol.) or the coupling is indirect via a His-kinase
and a Response Regulator as in case of the Histidine Kinase Rhodopsins of Chlorophyte algae(Luck et al. 2012).
We characterized two recombinant Rhodopsin-cyclases from Blastocladialla emersonii(BeRhGC) (Scheib et al. 2015 Sci Signal.) and Catenaria anguillulae (CaRhGC) (Scheib et al.
2018 Nat. Comm.) and have shown that both enzymes are completely inactive in the dark and are
active upon illumination. The enzymatically active state is formed within 10 to 40 ms after a flash
and decays within 100 to 500 ms depending on the species. The cyclases are highly selective for
GTP whereas ATP is acting as a competitive inhibitor. Coexpression of RhGC with a cGMPchannel from olfactory neurons and other sources in Xenopus oocytes , ND cells, HEK cells or
neurons generating a large photocurrent upon illumination and conferring a high light sensitivity
to the cell of interest. We are currently working on a cGMP-sensitive potassium channel in order
to use our Two-Component Approach for rhodopsin-based hyperpolarization in the neurosciences
and cell biology as we recently exemplified by combining the flavin-based photoactivated cyclase
bPAC with the small cAMP-activated K-channel Sthk (Bernal-Sierra et al. 2018 Nat. Comm).
In parallel we work on Chlamydomonas Histidine kinase rhodopsins (HKRs) from Chlamydomonas reinhardtii (Luck and Hegemann 2017 J.Plant Phys.; Luck et al. 2012 JBC) and Ostreococcus
tauri (Luck & Hegemann unpublished). Both are synthesized in the cell as blue-green sensitive
rhodopsins but are converted upon illumination into a UVA-sensitive species (Rh-UV) withmaximal absorption near 380 nm. The thermal stability of the Rh-UV is very high but varies
between many minutes to hours but it can be photochemically back-converted upon illumination
with UVA light. We propose that these HKRs developed in algae for measuring the ratio between
UVA and Blue light and to adapt cellular processes to this ratio accordingly. We are currently
deleting the 8 HKRs in C.reinhardtii by using a Cas9-based reverse genetics (Greiner et al. 2017
Plant Cell) to study the cellular function by comparing development and gene expression in wild
type and different deletion strains.

Session 3 : Light & Life; Optogenetics #2

Oscillatory control of somitogenesis and neurogenesis: imaging andcontrol of gene expression by light technology
Ryoichiro Kageyama(Kyoto University)
Somites, precursors for vertebrae, ribs, and skeletal muscles, are periodically formed bysegmentation of the anterior parts of the presomitic mesoderm (PSM). In the mouse embryo, thisperiodicity is controlled by the segmentation clock gene Hes7, which exhibits synchronous
oscillatory expression in the PSM. Without such Hes7 oscillations, all somites and theirderivatives are severely fused, but the detailed mechanism of synchronous Hes7 oscillations still
remains to be analyzed. We found that the Notch ligand Delta-like1 (Dll1) expression oscillates
in the PSM, and that when Dll1 expression was accelerated or delayed by shortening or elongating
the Dll1 gene, not only Dll1 but also Hes7 oscillations became dampened, leading to severe fusionof somite. Thus, the appropriate timing of Dll1 expression is critical for the oscillatory networks.
We also developed an optogenetic approach and found that intracellular and intercellular periodic
inputs of Notch signaling entrain intrinsic oscillations by frequency tuning and phase shifting.
Thus, the oscillation dynamics are transmitted through Notch signaling, thereby synchronizing
the population of oscillators. We now developed a real-time imaging system for analysis of Hes7
expression dynamics at a single cell resolution, using a new fluorescent reporter, and found that
the Notch signaling modulator Lfng regulates synchronized Hes7 oscillations by adjusting thecoupling delays.
Oscillatory gene expression is not unique to the segmentation clock but is observed in manycell types, including neural stem cells. In these cells, the cell fate determination factors
Ascl1/Mash1, Hes1, and Olig2, which regulate the fate choice of neurons, astrocytes, andoligodendrocytes, respectively, are expressed in an oscillatory manner. However, in eachdifferentiation lineage, one of the factors becomes dominant and is expressed in a sustainedmanner. We used optogenetics to control expression of Ascl1/Mash1, and found that althoughsustained Ascl1/Mash1 expression promotes neuronal fate determination, oscillatory
Ascl1/Mash1 expression activates proliferation of neural stem cells. Thus, the multipotent statecorrelates with oscillatory expression of several fate-determination factors, whereas thedifferentiated state correlates with sustained expression of a single fate-determination factor.
In my lecture, I will discuss the functional significance of gene expression dynamics indevelopmental processes such as somitogenesis and neurogenesis.

Session 3 : Light & Life; Optogenetics #3

Enzyme rhodopsins, potential optogenetics tools
for modulating intracellular cyclic-nucleotide levels
Satoshi Tsunoda1, 2, Kazuho Yoshida2, Leonid Brown3, Hideki Kandori2,4
1

JST PRESTO, 2Life Science and Applied Chemistry, Graduate School of Engineering, Nagoya

Institute of Technology, 3Department of Physics, University of Guelph, 4JST CREST

Function of microbial rhodopsins involve ion pump, ion channel, light sensor for phototaxis
response. Recent studies revealed novel rhodopsins with enzymatic functions such as
guanylate cyclase (Rh-GC) and phosphodiesterase (Rh-PDE)(1–3). Rh-GC functions as atightly light-regulated guanylate cyclase whereas only a weak light dependency wasdemonstrated in Rh-PDE when studied in heterologous expression systems. These molecules
could be genetically targeted into various types of cells, serving as optogenetics tools for
optical control of intercellular cyclic nucleotide-associated signal transductions.
To get deeper insights into the light-activation mechanism of Rh-GC and Rh-PDE, we here
investigate the spectroscopic property, enzymatic kinetics, and evaluate the light-dependent
activity in mammalian cells. Mutation studies were performed to identify critical residues for
enzymatic activation.

References
1.

Scheib, U. et al. 2015. Sci. Signal. 8: 1–9.

2.

Gao, S. et al. 2015. Nat. Commun. 6: 8046.

3.

Yoshida, K. et al. 2017. J. Biol. Chem. 292: 7531–7541.

Session 3 : Light & Life; Optogenetics #4

FTIR study of photoactivated cyclase
Daichi Yamada
Nagoya Institute of Technology
Cyclic adenosine monophosphate (cAMP) is one of the most important second
messengers, regulating many crucial cellular events in both prokaryotes and eukaryotes,
and precise spatial and temporal control of cAMP levels by light shows great promise asa simple means of manipulating and studying numerous cell pathways and processes [1].
The photoactivated adenylyl cyclase from the photosynthetic cyanobacterium
Oscillatoria acuminata (OaPAC) are powerful tools for optogenetics and for investigating
signal transduction mechanisms in biological photoreceptors [2]. The OaPAC has twodomains: N-terminal blue light using flavin (BLUF) domain and C-terminal adenylyl
cyclases (AC) domain. The Structural changes of the BLUF domain lead to changes of
the AC domain, although the underlying mechanism remains unknown.
Here, we attempted to monitor the structural changes of OaPAC for understanding thelight-regulated mechanism by using FTIR spectroscopy. We obtained the temperaturedependence light-induced difference spectra which are supposed to reflect structuralchanges of the enzyme domain in Amide I region, by comparing the results between
OaPAC full length and without AC domain. Additionally, in order to investigate thestructural changes due to enzyme activity from ATP to cAMP, we compared light-induced
difference FTIR spectra of OaPAC full length in the absence and presence of ATP. In thephotoreaction, differences were observed in the phosphate backbone reflected the change
from ATP to cAMP, and the band considered as Asp residue necessary for enzyme activity
were observed. We would like to discuss the light-regulated mechanism of OaPAC, basedon these obtained results and together with mutation data.

[1] Rost et al., Neuron 96, 572-603, 2017[2] Ohki et al., Proc. Natl. Acad. Sci. USA. 113, 6659-6664, 2016; Proc. Natl. Acad. Sci.
USA. 14, 8562-8567, 2017

Session 3 : Light & Life; Optogenetics #5

Optochemical control of protein localization in living cells usingsynthetic organic molecules
Tatsuyuki Yoshii1, 2, Choji Oki1, Shinya Tsukiji1(1Nagoya Institute of Technology, 2JST-PREST)
Proteins rapidly and dynamically changes their localization during cell signaling. Thus,
tools for rapid control of protein localization would arrow spatial and temporal
manipulation of cell signaling and behavior. Chemically-synthesized molecule has
potential to be a powerful tool because chemists can design and tune the property ofphoto-responsive group including wavelength and reversibility. However, opto-chemical
control of protein localization without using chemically induced dimerization (CID) has
not been explored due to the lack of the design to target small molecule to specific cellularorganelle.
Here, we describe a protein translocation system by using photo-responsive, self-

localizing ligand (pSLL). We designed a pSLL which consists of an organelle targeting
motif and protein ligand protected by photo-removal group. We selected a lipopeptide

motif to target the inner leaflet of plasma membrane (iPM). For the protein ligand, wechose trimethoprim (TMP) which binds to Escherichia coli dihydrofolate reductase(eDHFR). The amino group of the TMP was protected by nitroveratryloxycarbonyl(NVOC) group. The proof principle experiment was performed using Hela cells

expressing eDHFR-mScarlet-i. When the pSLL was incubated with cells and irradiatedwith 405 nm light, rapid translocation of e eDHFR-mScarlet-i from the cytosol to the iPM
was observed. We also applied this system to control Rac1 signaling in NIH3T3 cells byphoto-induced translocation of Tiam1, a guanine nucleotide exchange factor for Rac1.
NVOC
lipopeptide

TMP

Spontaneously
localize to iPM

hv
DHFR

Translocation

Inside cell

Plasmamembrane

POI

DHFR

POI

Figure 1. Opto-chemical control of protein localization using pSLL

Session 4 : General Light & Life #1

Exotic Behavior of Water Around the Anti-Freeze Protein:
Large-Scale Molecular Dynamics Simulations
Shuji Ogata1 and Yasuhiro Kajima2
1Nagoya Institute of Technology
2Nagoya Zokei University
Various northern fishes, insects, and plants inhabiting under the sub-zero temperatures
conditions synthesize a certain type of proteins to avoid freezing. These proteins are called antifreeze proteins (AFP). They are believed to show the anti-freeze ability by binding to water-ice
interfaces of emerged ice particles and thus inhibit their growth by Kelvin effect, resulting in
melting point depression. However, neither detailed mechanism of the bindings nor the reasons
why these proteins inhibit ice growth are known. The theoretical understanding of the anti-freezemechanisms will aid in the proposal of, e.g., a novel snow melting agent.
Motivated by that, we perform two kinds of molecular dynamics simulations to unveil themechanisms of type-I AFP. (i) One is large-scale (millions of atoms) simulations to see the ice
growth after AFP's (PDB ID: 1j5b) areplaced on the ice-water interface, whichcorrespond to the situation where ice
particles are formed in a supercooled water.
We thereby confirm that the ice growthsignificantly slows down at a supercooledtemperature (see Fig. 1). The AFP stabilizes
most when the OH/CO groups face thewater and the CH3 groups fit within the
trench structure of the ice surface. (ii)
Another is medium-scale (tens of thousandsof atoms) simulations to find the behaviors
of water molecules around the amino
residues that constitute the AFP. We thereby
find that the microscopic structure of watermolecules around the amino residues varies
depending on the choice of the amino
residues. Relation of the finding to the antifreeze ability of the AFP will be explainedin the presentation.

Fig. 1. Snapshot at 12 ns of the large-scale MD
simulation of the ice-water interfacial systemwith 12 AFPs at 260 K. The yellow lines
indicate the initial position of the ice-waterinterfaces.

Session 4 : General Light & Life #2

Effect of third component in bulk-heterojunction organic solar cell
Tetsuo Soga, Naoki Kishi, Shinya Kato
Department of Electrical and Mechanical Engineering,
Nagoya Institute of Technology, Japan
Organic solar cells have attracted attention since bulk heterojunction was developed in theearly 1990s. The advantage of organic solar cell is not only the high efficiency and low cost but
also the new functions such as flexible, semi-transparent, light-weight, etc. Recently, the energy
conversion efficiency higher than 17 % has been achieved by using tandem structure made of
new polymer material [1], and more than 20 % efficiency is expected in the future [2].
In order to improve the efficiency of organic solar cell furthermore, a lot of approaches havebeen employed until now. However, there are still many unknown points to understand theoperation of organic solar cell. Normally the organic solar cell is composed of donor material
and acceptor material sandwiched between two electrodes (or electron/hole transport layer).
One way to improve the performance is to dope third component in the donor/acceptor materials.
This presentation describes the effect of addition of organic or inorganic third component
materials on the photovoltaic properties of organic solar cells.
Regioregular poly(3-hexylthiophene-2,5-diyl) (P3HT) and [6,6]-phenyl-C61-butyric acidmethyl ester (PCBM) were used as donor material and acceptor material, respectively. The
active layer was a blend film of donor material and acceptor material which was prepared byspin coating on PEDOT-PSS (Poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate)) holetransport layer prepared on ITO-coated glass substrate. The Al electrode was evaporated on theactive layer by thermal evaporation. The fundamental solar cell structure and fabrication
procedure are reported in refs. 3 and 4. MEH-PPV (2-methoxy,5-(2′ethyl hex-yloxy)-PPV),polyethylene glycol, ZnO nanoparticle etc were used as third component. The effects of thesethird components on the photovoltaic properties of organic solar cell are described at thepresentation
Reference[1] L. Meng, Y. Zhang, X. Wan, C. Li, X. Zhang, Y. Wang, X. Ke, Z. Xiao, L. Ding, R. Xia, H-L.
Yip, Y. Cao and Y. Chen, Science, 2018, DOI: 10.1126/science.aat2612.
[2] A. J. Heeger, Advanced Materials, 26 (2014) 10.
[3] S. Saravanan, Y. A. M. Ismail, M. Silambarasan, N. Kishi, T. Soga, Advances in Energy
Research, 4 (2016) 275.
[4] Y. A. M. Ismail, N. Kishi, T. Soga, Thin Solid Films, 616 (2016) 73.

Session 4 : General Light & Life #3

Functional Extension and Linkage of Photosynthetic Biohybrid Light–
Harvesting/Reaction Center Complexes in Artificial Systems
Takehisa Dewa
(Department of Life Science and Applied Chemistry, Graduate School ofEngineering, Nagoya Institute of Technology)
Light-harvesting strategies are of crucial importance for the establishment of renewableenergy production systems that can utilize solar energy with high efficiency. In terms ofartificial photosynthesis, so called “photon flux density problem” should be overcome throughdevelopment of light-harvesting systems that efficiently collect light energy to transfer it to an
active site in a catalyst so as to provide high turnover frequency. In photosynthetic membranes,
densely packed light-harvesting (LH) and reaction center (RC) complexes perform highly
efficient energy conversion from light energy to chemical potential. Recently, we successfully
extended light-harvesting ability of photosynthetic light-harvesting complex (LH2) from apurple bacterium through attachment of artificial fluorophores (Alexa Fluor 647: A647), which
can expand the range of wavelength of light energy acquired. Femtosecond transient
spectroscopy revealed that energy transfer from A647 to the intrinsic chromophores
bacteriochlorophylls (BChls) occurs in sub picosecond to several dozen picoseconds time range[1]. When a hydrophobic fluorophore (Atto647N: AT647N) was used for the auxiliary
chromophore attached to LH2 (LH2-AT647N), the energy transfer rate was significantly
accelerated in the time range of sub picosecond to several picoseconds in a lipid bilayer
environment. In this study, we addressed a combination of the biohybrid light-harvesting
complex (LH2-AT647N) and a bacterial light-harvesting 1/reaction center core complex(LH1-RC) to show a cooperative effect of light harvesting and chemical reaction, i.e., charge
separation and photocurrent generation, the latter of which results from the catalytic photocyclein RC. Recently, we have reported that LH1-RC from a purple photosynthetic bacterium (from
Rhodopseudomonas palustris) effectively generates photocurrent when assembled with lipid
bilayer on an ITO electrode [2]. When LH2-AT647N and LH1-RC (1/1 mixture) in lipid bilayer
were placed on the ITO electrode, enhanced photocurrent was observed upon irradiation at 650
nm (absorption maxima of AT647) compared with a LH2/LH1-RC system. Action spectra were
evident for the contribution of AT647N to photocurrent generation. The enhancement ofphotocurrent generation activity is due to increase in apparent absorption cross-section of
LH1-RC.
[1] Y. Yoneda, et al., J. Am. Chem. Soc., 2015, 137, 13121.
[2] T. Noji, et al., J. Phys. Chem. B 2018, 122, 1066.

Session 4 : General Light & Life #4

Multiscale Modeling of Electrostimulation
Akimasa Hirata
Dept. Electrical and Mech. Eng., Nagoya Institute of Technology, JapanFor the past 30 years, there has been significant progress in biophysical andelectrophysiological modeling simulation techniques to evaluate electromagnetic field
effects in the human body. Historically, the electromagnetic modeling techniques havebeen developed to clarify potential adverse health effect from the external
electromagnetic field. However, most effort has been devoted into the macroscopic
modeling, where the nerve activation was not considered. In addition, the phenomena
one would like to know the response from external physical quantities. To understandthe response from external physical quantity, three steps are needed.
The first step involves expressing a human body composed of the smallest elements(voxels) with a resolution of several millimeters based on medical images on thecomputer. The research necessity in this field is well summarized in Reilly and Hirata(Phys. Med. Biol. 2016). The second step involves the computation of theelectromagnetic field and is achieved by assigning different electrical characteristics foreach human tissue to each voxel/element constituting the model. The third step involves
modeling the effect of the in situ electric current on the propagation of the neuronalsignals. We included a new step that corresponds to the integration of local and remote
circuits by synaptic modeling (Gomez-Tames and Hirata, Int’l J. Neural Sys. 2018).
In this study, we review the multiscale modeling of electrostimulation and resultant
response with computational techniques. In particular, the brain stimulation andmagnetophosphene from an external magnetic field are explained as computational
examples. The limitation of the current status of the techniques is attributable to thesynaptic effect which has not yet been well modeled even in typical biological response.