OCARINA Communication 4—Special Project—
Present State of the Tenure-track Project and its Prospects“Present State of the Tenure-track Project and its Prospects”
Discussion with researchers invited through the Tenure-track Promotion Project—Research Introduction—
Yoshimasa Fukushima

OCU Advanced Research Institute for Natural Science and Technology
Specially Appointed Assistant Professor“Toward X-ray crystallography on the reaction intermediate of Photosystem II”
Hajime Masukawa Special-appointment Associate Professor, OCARINA“Improvement of photobiological hydrogen production by heterocystous N2-fixing cyanobacteria”
Yoshihiro Yamaguchi Tenure-track Associate Professor“Why bacteria contain many TA systems?”
Tomoyasu NojiThe OCU Advanced Research Institute for Natural Science and Technology (OCARINA)
Special-appointment lecturer“Tenure-track Associate Professor”—Facility Introduction—

Artificial Photosynthesis Research Center Analysis Equipment—Activity Report—

The 2013 OCARINA Annual International Meeting
OCARINA Seminars
The first Osaka City University Tenure
Track Teachers Research Presentation Event

The OCU Advance Research Institute for Natural Science and TechOCARINA Communication 4■ Special Project: Present State of the Tenure-track Project and its Prospects“We hope to grow as researchers and educators, making use ofa research environment that integrates humanities and sciences.”
Discussion with researchers invited through the Tenure-track Promotion Project1
Osaka City University started the Tenure-track Promotion Project in 2014 to establish a research
environment in which young researchers would be able to study independently. This is part of a
project conducted by the Ministry of Education, Culture, Sports, Science and Technology, and an
unprecedented undertaking for our university.
We are presenting a discussion by the three tenure-track teachers belonging to the OCU Advanced
Research Institute for Natural Science and Technology, Prof. Amao, their mentor, and Vice President
Miyano.

A Wide Variety of Fields of Study – The
Advantage of a Comprehensive University
Offering Both Humanities and Science
Programs
Dr. Miyano／Only a few municipal universities have been
selected for the tenure-track promotion project of the
Ministry, and we are proud to be one of them. I am truly
pleased to have such brilliant teachers as you with us.
It is my understanding that one of the reasons ouruniversity was selected for the project was that we offerwell-balanced fields of study in both the humanities andsciences, and have a high potential for their integration,even though our university is not as big as the major
national universities.
Also, both the Advanced Research Institute for Natural

Science and Technology and the Urban Research Plaza, towhich the tenure-track teachers belong, are conducting
state-of-the-art research, and they are also engaged inprograms with foreign institutes involving the acceptance of
researchers from abroad.
Almost one year has passed since you three joined theAdvanced Research Institute. Could you tell us yourimpressions of our university, your research topic and yourhopes?
Dr. Amao／Our tenure-track project was launched inAugust of 2013, and we soon began recruiting. I suppose it
might have been difficult to prepare in a short time. Could
you tell us why you decided to apply to our university?
Dr. Nakadai／It was just when I was starting my 10th year

The OCU Advance Research Institute for Natural Science and TechOCARINA Communication 4

after obtaining my degree. The time limit to apply for thetenure-track project is within 10 years of obtaining a
degree. I was thinking about becoming an independent
researcher in the future. Then, Dr. Nishikawa of thisuniversity posted the in formation about the open
recruitment of researchers of nematodes on the mailing list.
The field of recruitment was slightly different from mymain field of study, but Dr. Nishikawa also deals withnematodes as his model animals; therefore, I expected thatmy research topic might be accepted, and applied for the
recruitment.
Dr. Yamaguchi／I had been conducting research in the
U.S.A., and it was time for me to decide whether to staythere and acquire permanent residency or go back to Japan.
There are many independent researchers in the States, andI also hoped to establish my own project and conduct
research independently. I looked for the recruitment
information of many institutions and found the recruitmentof OCU. There was an English website, so I expected thatapplications from countries other than Japan would also be
accepted.
Dr. Amao／I was present at your interviews, and I was
impressed by Dr. Yamaguchi’s presentation given in
English. Dr. Asoh, you applied for the field of chemistry,
which was highly competitive. Why did you decide to apply?
D r. A s o h／L i ke the other two, I wa s seek i ng a nenvironment that would give me independence. I had beenworking as an assistant professor at Tokyo University of
Science and looking for an opportunity to become
independent, so I was paying attention to information about
the recruitment of tenure-track teachers. I thought
tenure-track status with abundant funds would be ideal formy purposes. This university offered chances for a wide
range of fields of chemistry, so I expected that bio-material,
my field of study, would be included.
Dr. Miyano／All of you hoped to be independent, as I
assumed. The Tenure-track Project aims to provide
researchers with an opportunity to study independently;
therefore, it goes along with your purpose. Didn’t you have
any hesitation in applying to a municipal university rather
than a national university?
Dr. Asoh／This university is a comprehensive university
offering both humanities and science courses, and it is notinferior to national universities. I did not worry with regard
to that point.

Dr. Yamaguchi／I was teaching at a state university in the
U.S.A., so the type of organization was not important to me;what was important was to be able to conduct research as I
wanted to.
Dr. Nakadai／I did not mind the fact that this university ismunicipal, but I had little information about OCU since I’mfrom Kyushu. I asked my husband, who is from the Kansai
District, and he told me that this university is a good,comprehensive university, so I decided to apply.

Expansion of the Fields of Research throughthe Tenure-track Project
Dr. Amao／I appreciate your comments. Now, could you
please give a brief outline of your field of research.
Dr. Nakadai／I am studying the mechanism of byophylaxis,
using the model animal C.elegans , which is a 1mm-longnonparasite nematode. For all creatures including humans,
it is a kind of biophylaxis to perceive danger by means of theneural system and senses. I am analyzing the actions ofsensing and avoiding danger, using nematodes. I am also
studying the mechanism of biological response to infection
at the levels of individual cells and molecules.
Dr. Yamaguchi／The types of microorganisms that I am
studying are bacteria. In general, bacteria do not have apositive image, but they have been recently found to produce
a toxin that could kill them. Almost all of the bacteria thathave been found so far have a similar toxin, but we have notdiscovered the reason yet. The targets of each toxin are
different, and the study of the targets is also interesting. I
think if we can make use of such toxins, they can be applied
to the treatment of HIV or cancer.
Dr. Asoh／I am conducting research on polymer bio
material. Basically, I am studying the chemical design ofmaterials that are used in or on the human body. My
ultimate, major goal is the study of artificial muscle.
Dr. Amao／The three of you now belong to a department of
the Advanced Research Institute or another affiliatedsection. I hope you will establish a new field of study there
in the future.
Dr. Miyano／The Advanced Research Institute now focuseson the research of artificial photosynthesis, but it was
originally expected to cover a wide range of science.

The OCU Advance Research Institute for Natural Science and Tech

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OCARINA Communication 4■ Special Project3

Director/ Vice President, OCU

Professor, OCARINA

Michio Miyano

Yutaka Amao

Completed the doctoral program of the Graduate School ofEngineering, Tokyo Metropolitan University in March 1980
without obtaining a doctorate. Obtained a degree of Doctor ofEngineering. Was a full-time lecturer, professor, Dean of the
Graduate School of Human Life Science and the Faculty of Human
Life Science of OCU, and became Vice President in 2010. His books
include “Great East Japan Earthquake - Volunteering Activities andTemporary Housing” (Kenpakusha, 2014), “Long-period Ground
Motion and Seismic Resistance of Buildings” (Architectural
Institute of Japan, 2007), “Disaster Prevention Encyclopedia”(Tsukiji-shokan, 2002) and “Great Hanshin Earthquake - Short yet
Long Five Years” (Gakugei Publishing, 2000).

Professor, OCARINAZObtained a Doctorate inEngineering at the Graduate School of Bioscienceand Biotechnology, Tokyo Institute of Technology inMarch 1997. Was a researcher at the Kanagawa
Academy of Science and Technology Foundationand the National Aerospace Laboratory of Japan(present-day JAXA). In addition, he was a lecturer, anassistant professor, and then an associate professor
at the Faculty of Engineering, Oita University. He
became a professor of OCARINA in April 2013. He has
also been a pioneering researcher at the Japan
Science and Technology Agency since April 2010.

The expansion of the fields due to your research is awelcome development.
The most important objective is for you to gain thecapabilities to become independent, and to accomplish many
projects during your tenure-track term. Please let us know
about any requests or proposals for improvement of oursystem that you may have thought of through conducting
your research.

still not very familiar with this university.

Dr. Nakadai／This is the first period of the project and thatmight be the reason, but I sometimes feel that the term
“tenure-track” and the system itself have not been widely
recognized.

Dr. Yamaguchi／Thank you very much. In that sense, it
was good that many teachers attended the research reportmeeting the other day. I think that they have been
gradually gaining an understanding of our research.

Dr. Miyano／The system has definitely not been sufficiently
recognized, particularly among teachers of liberal arts. We
began the Tenure-track Project in the fields of science first,
although we hope to spread it into the fields of humanities
in future. The project is sometimes discussed at themeetings of professors of the three graduate schools ofscience, engineering and human life science, so the teachersof these schools should know about the system. However, weshould publicize the system to disseminate the information
more widely.

Dr. Asoh／I do not have any problems at the moment.
Three teachers have constantly been following my research.
I give them reports on the progress of my research, and they
conduct a strict check once every two months. First, I had
some difficulty in understanding my position; however,partly because of the characteristics of this region, Osaka, I
feel very close to them and it is easy to communicate, since
they honestly give me both good comments and harshcomments.

Dr. Yamaguchi／I am really grateful that not only theteachers of the Graduate School of Science but also otherpeople care about me, since I started my research here.
Many of them often ask me if I need something or talk tome every time they see me. My only trouble is this: therea re ma ny i nstr u ments I wou ld l i ke t o use i n myexperiments, and I guess they might be used by someone at
another graduate school, but I do not know how to contact
them. Of course, I have only been here one year, so I am

Dr. Miyano／Other teachers might have the same problem
with regard to sharing the experimental instruments. This
also needs to be publicized. We will provide information
about the tenure-track teachers regarding which sections
they belong to and what they are studying so that you cancollaborate with other teachers.

Dr. Amao／You are the advisor of two chemistry students,
Dr. Asoh. In the future, you will be required to have theskills of an educator. I think you should start gaining
experience in endeavoring to train good students.
Dr. Miyano／I agree. It is definitely an important goal for
you to be an independent researcher, but I hope you will
also improve your ability to teach students. Please commit
yourself to education during this period to the extent that it
will not be detrimental to your research. As part of thisThe OCU Advance Research Institute for Natural Science and TechOCARINA Communication 4

Specially appointed tenure-track lecturer,
Graduate School of Science (Chemistry), OCARINA

Specially appointed tenure-track associate professor,
Graduate School of Science (Biology), OCARINA

Taka-aki AsohYoshihiro Yamaguchi

Research theme: “Development of
Stimulation-responsive Polymer Materials that Act in an
Aquatic Environment” and “Construction of
Next-generation Materials by the Bonding of Hydrogel”
Obtained a Doctorate in Engineering at the Graduate
School of Engineering, Osaka University in March 2008.
Was a fellowship researcher of the Japan Society for the
Promotion of Science (DC2, later PD) and an assistantprofessor of the Faculty of Industrial Science andTechnology, Tokyo University of Science, and joined
OCARINA in March 2014.

Research theme: “A Study on the PhysiologicalRole of Apoptosis-like Cell Death inMicroorganisms”
Obtained a Doctorate in agricultural science in the
post-doctorate course at the Graduate School of
Agricultural Science, Tohoku University in 2005.
Was a fellowship researcher of the Japan Society
for the Promotion of Science (DC2), a post-doctoral
researcher and a Research Teaching Specialist III of
Rutgers University. He joined OCARINA in 2014.

Tenure-track Promotion Project, it is also necessary to train
young researchers who will follow in your footsteps. I hopethat you will have many experiences of collaboration with
graduate students and young researchers that you will beable to apply to education.

A New Challenge Identified at the Research
Report Meeting
Dr. Amao／I hear that there was a large audience at the
research report meeting Dr. Yamaguchi mentioned earlier.
Did you find anything difficult in reporting your research
results?
Dr. Asoh／Not really. I emphasized the fact that I had
started something new.
As for the commentator, the one in the field close to mine
could not attend the meeting, but a renowned researcher inthe field of polymers, who is my mentor’s superior, attended
the meeting and gave a comment from a perspective
different from ours. That was very meaningful. After thepresentation, the director of OCARINA gave me a lot of
encouragement, and I renewed my determination to work
hard.
Dr. Yamaguchi／At the meeting, I learned about what othertenure-track teachers were working on. I did not know how
I should explain my topic to the teachers of fields of study
that are totally different from mine, and I could not manage
my reporting time well. However, I was very inspired by thequestions, which were from a wide range of perspectives.

opportunity to explain my research. Also, I think I shouldhave been aware of the audience and explained in such a
way that people of different fields could understand easily,
since I started with very technical topics.
Dr. Amao／You are still young, so I recommend that you
use this kind of report meeting as a means of accumulating
experience in preparation for applying for JST’s PRESTO(Sakigake) program and other subsidized research
programs that involve hearings as part of the approval
process. My research was adopted for PRESTO, and when I
was applying for that, I felt the same way as you did; since
the judges were not from the same field as me, I should havegiven a more detailed introduction and talked about basic
things. If you are in the same situation, I will give you
advice, so please let me know. Securing research funds is an
important process for advancing your career.

Aiming to Be a Researcher Who Can Give
Students Dreams
Dr. Amao／Finally, do you have an image in your mind of
the kind of teacher you would like to become?
Dr. Asoh／I hope to be a strong researcher. I would like tocontinue with the research that I want to do, be arecognized researcher and an educator who can convey
what I have learned to students. In addition, I think I will
be rigorously evaluated over the next five years, so I willtrain myself mentally and physically to steadily acquirecapabilities. Ultimately, I aim to become a full-fledged
researcher and educator.

Dr. Nakadai／Yes. I also think that it was a good

The OCU Advance Research Institute for Natural Science and Tech

4

■ Special ProjectSpecially appointed tenure-track associate
professor, Graduate School of Human Life Science(Food and Nutrition), OCARINA

Eriko Nakadai
Research theme: A Study of the Molecular Base in
Organisms for detection of and Protection from
Environmental StressObtained a Doctorate in Pharmaceutical Science at theGraduate School of Pharmaceutical Sciences, Universityof Tokyo in 2004. Was a researcher for a pharmaceuticalcompany, an assistant professor and lecturer of the
School of Medicine, Tokyo Women’ s Medical University,and joined OCARINA in February 2014. She also belongs
to the Graduate School of Human Life Science.

Dr. Yamaguchi／I have long aimed to become a researcher
who continues to take on challenges and enjoy science;
however, I need to not only conduct research but also
educate students for these five years. I think the best thing
will be for me to spend time with students in a meaningful
way, and let them know that science is enjoyable.
Dr. Nakadai／What I want for my students is for them tobecome strong. I hope to support them in becomingstrong researchers and educators. Also, there are manyfemale students in the graduate school, and I will behappy if seeing me working inspires them to pursue a
career as a researcher.
Dr. Miyano／I think all of us decided to become researchers
because we had a good mentor, a model researcher whom
we aimed to resemble. As Dr. Nakadai said, I hope you will
be a researcher who will be able to give dreams to young
people. This will be an important perspective when you
begin to teach students as an independent researcher.

Soon, there will be new, young graduate students. I would
like to have opportunities to communicate with themthrough you.
Dr. Amao／It may be a good idea to use this institute forthat purpose, and to start some kind of an association foryoung members. Providing an occasion for students ofdifferent fields to get together may lead to innovative ideas.
Dr. Miyano／There are many researchers in this institute
who study in fields such as artificial photosynthesis that do nothave much to do with my own field, and I have a number ofopportunities to obtain inspiration from them. I hope you will
also make use of this kind of environment. Speaking of theuniversity as a whole, there are many fields that haveintegrated humanities and sciences. Please take advantage ofthis feature as well.

■ Research Introduction
OCU Advanced Research Institute for Natural
Science and Technology Specially Appointed
Assistant Professor

Yoshimasa Fukushima
Toward X-ray crystallographyon the reaction intermediate of
Photosystem II

B.S. in Physics, Nagoya University School of
Science. M.S. and Ph. D., Nagoya Univ. Graduate
School of Sciences. After serving as a researcher at
the Nagoya Univ. Graduate School of Sciences andthe same university’ s Center for Gene Research,began serving in his current position in November,
2012

Photosystem II (PSII) is a membrane protein complex

by EPR spectroscopy on our PSII solution, that the S2 state

which undergoes a primary reaction of photosynthesis.

was induced and trapped by illumination at the cryogenic

PSII binds oxygen-evolving complex (OEC) that catalyzes

temperature. The similar protocol may be available to

the water-splitting and oxygen-evolving reaction. The

achieve the S2 state in crystals, however, we have tostructural model of OEC at a resolution of 1.9 Å has been

overcome a problem in the case of XRD. The matter is thereported on 2011 (Umena, Kawakami, Shen, and Kamiya,

ice formation in protein crystals. If the protein crystal

Nature, 2011, 473, 55-60). In order to elucidate further thecontains ice, it will perturb the diffraction pattern from theprinciple of oxygen-evolving photosynthesis, we areprotein crystal, and the dataset quality may become quite

studying about light-induced structural-change of PSII.

low. In general, the ice formation can be prevented by

PSII exists in thylakoid membrane of plants andadding of cryoprotectants, such as polyethylene glycol, into

algae, performing the water splitting and intra-proteina crystal-enfolding solution. We examined for experimental

electron-transfer reactions. PSII contains many cofactors

conditions that suppress the ice formation, changing thesuch as OEC, chlorophylls, carotenoids and plastoquinones,

crystal-enfolding solution to oils and modifying

among which electron transfers take place. The functional

crystal-cooling protocol. Recently, we found out a newrole of OEC is the oxidization of water molecule and thecondition that suppresses the ice formation at the

donation of electron to other cofactors. It has been known

temperature around 240 K, which will enable the structurethat OEC has five intermediates in the PSII reaction

analysis of PSII at the S2 state.

(Figure). These five states have different oxidation
numbers and alter sequentially by individual photon
absorptions. These intermediates are denoted as S1, S2, S3,
S4, and S0. S1 is the most stable state under dark
condition. Molecular models in the S2 state have been
proposed by spectroscopic techniques, such as EPR and
XAS. On the other hand, by protein crystallography or
X-ray diffraction techniques (XRD), there is no knowledge
about the S2 state structure at high resolutions, at whichwater molecules can be distinguished obviously. It is
important to clarify the structure of water molecules in
PSII, because PSII utilizes water molecules as thesubstrate. We are focusing on the structure analysis of theS2 state by XRD.
Spectroscopic researches previously reported haveelucidated that the S2 state can be trapped at a
cryotemperature range of 200 – 240 K. We also confirmed,

■ Research Introduction
Special-appointment Associate Professor,
OCARINA

Hajime Masukawa

Improvement ofphotobiological hydrogenproduction by heterocystousN2-fixing cyanobacteria
Photobiological production of H2 by cyanobacteria is an
attractive source of renewable energy because thesemicroorganisms have simple needs: readily available
sunlight for energy and water as the electron donor. H2 isan efficient substrate for fuel cells that cleanly generate
electrical and thermal power with water as the final
product.
In cyanobacteria, H 2 gas is generated by eitherhydrogenase or nitrogenase. Both enzymes are sensitive toinactivation by O2. In contrast to hydrogenase, nitrogenasecatalyzes the following reaction under optimal conditions
for N2 fixation:
N2 + 8e- + 8 H+$73ĺ+2 + 2 NH3 + 16 (ADP + Pi ) (1)Whereas, in the absence of N2 (e.g., under Ar), all electrons
are allocated to H2 production:
2 e- + 2 H+$73ĺ+2 + 4 (ADP + Pi ) (2)The above reactions are essentially irreversible andthus nitrogenase does not consume H2 as a substrate. For
the heterocystous N 2 -fixing cyanobacterium used here,
Anabaena sp. strain PCC 7120, nitrogen deficiency leads tothe development of specialized cells called heterocysts.
Heterocysts lacking photosystem II activity, have increased
respiration and are surrounded by a thick cell envelopethat impedes the entry of O 2 , providing a microaerobic
environment to protect the nitrogenase from inactivation
by O2 (Fig. 1). Because of their ability to generate energy byoxygenic photosynthesis while forming a separate space foranaerobic reactions, heterocystous cyanobacteria are goodcandidates for optimization of photobiologicalnitrogenase-based H2 production through gene engineering[1,2].
One of the major obstacles to efficient solar energy
conversion to H2 is the presence of the uptake hydrogenase(Hup) that reabsorbs the H 2 produced by nitrogenase.
When the Hup activity is eliminated by genetic
engineering, the cyanobacterial mutants showed 3-7 foldReceived a Ph.D. (Doctor of Science) from Waseda University
in March 2003. He previously worked as a postdoctoral fellow
at Advanced Research Institute for Science and Engineering,
Waseda University, an assistant professor at Department of
Biology, School of Education, Waseda University, JSPS
Research Fellow (PD) at Kanagawa University, Research
Associate at DOE Great Lakes Bioenergy Research Center and
Department of Microbiology and Molecular Genetics,
Michigan State University, and JST PRESTO researcher at
Kanagawa University. He has been in his current position
since October 2014.

increased H2 production activity under Ar gas comparedwith wild-type cells and accumulated a high concentrationof H2 (about 7-30%) even in the presence of O2 [1,2].
According to equations (1) and (2), one expects to beable to increase the H2 production activity of nitrogenase by
decreasing the electron allocation to N 2 fixation.
Mutagenesis of nitrogenase offers an alternative
mechanism to redirect electron flow and overcome N 2competition which causes a decrease in H 2 production
activity in the presence of N 2 . In an attempt to directelectron flow selectively toward proton reduction in thepresence of N2, 49 variants with amino acid substitutions
presumed to be located in the vicinity of the catalytic
1Mo-7Fe-9S-1C-homocitrate] FeMo-cofactor of nitrogenase
were constructed [3]. Some of the variants photobiologically
produced H2 under N2 at rates comparable to those under
Ar over the course of several days (Fig. 2). Of the variants,
the two mutants, Q193S and R284H, rapidly produced H2under N2 -rich gas at higher sustained rates than underAr-rich gas over 3 weeks [4]. These site-directed variants
have a potential cost advantage in sustaining H2 production
at high rates by periodic gas renewal using the lessexpensive N2 gas without changing the culture medium.

References[1] Masukawa H. et al., Ambio 41, 169-173 (2012).
[2] Sakurai H., Masukawa H. et al., J. Photochem. Photobio. C 17, 1-25 (2013).
[3] Masukawa H. et al., Appl. Environ. Microbiol. 76, 6741-6750 (2010).
[4] Masukawa H. et al., Int. J. Hydrogen Energ. 39, 19444-19451 (2014)

Fig. 1 Photobiological H2 production by heterocyst-forming cyanobacteria (adaptedfrom [ref. 1])

Fig. 2 In vivo H 2 production activity of the several nitrogenase active sitevariants under Ar or air

■ Research Introduction

Tenure-track Associate Professor

Yoshihiro Yamaguchi
2005 Graduate School of Agricultural Science,
Tohoku University
2006 Postdoctoral fellow, Rutgers University.
2010 Research and teaching specialist III, Rutgers
University.

Why bacteria contain many TA
systems?
Regulation of cell death is essential for living organisms.
In the eukaryotes, apoptotic cell death is crucial fordevelopmental process, for maintenance of normal cellhomeostasis as well as for elimination of cells damaged bystress or pathogen infection. In bacteria, regulation of cell
growth and cell death is also important under various stressconditions. Almost all bacteria contain genes encoding asmall toxin protein consisting around 100 amino acidresidues, which targets various cellular processes including
DNA stability, DNA replication, mRNA stability, protein
synthesis, cell-wall biosynthesis and ATP synthesis to inhibit
cell growth (Figure 1) 1,2) . In normally growing cells,
however, these toxins are co-expressed from an operon with
their cognate antitoxins forming a stable toxin-antitoxin(TA) complex so that the toxicity of the toxins cannot be
exerted. This growth-regulatory system is called atoxin-antitoxin (TA) system.
The TA systems are not essential for normal cell growth,
nevertheless they are widely prevailing in bacteria andarchaea. This fact suggests that they may have been playing
subtle, advantageous roles for cells to survive in their natural
habitats, for example, in cellular adaptation to ever changing
natural habitat by either reducing the growth rate orcompletely inhibiting cell growth or leading some cells todie. A TA system was first identified on a plasmid, whichplays an essential role in plasmid maintenance. When aplasmid encoding the TA system is lost from a cell, the toxin
is released from the existing TA complex, since the antitoxin
is more unstable than toxin. This results in cell growth
inhibition and eventual cell death. Since this discovery, anumber of different TA systems have been identified to be
encoded from bacterial genomes. The toxins from these TA
systems are proposed to be associated with various cellular
processes in regulating gene expression, bacterial population

control and programmed cell death.
Until now, there are about 50 different types of TA
systems have been found in bacteria. It is interesting to notethat Mycobacterium tuberculosis contains more than putative
80 TA systems, while its nonpathogenic counterpart, M.
smegmatis has only two putative TA systems. It seems thatthe number of TA systems may be related to thepathogenicity of M. tuberculosis, and the TA systems in thispathogen may play important roles in the maintenance ofthe extremely long dormancy of this bacterium insidemacrophage. On the basis of this consideration, it is perhaps
surprising that E. coli also contains comparatively a large
number of TA systems.
Since these TA systems have likely been maintained
through the evolution, one may speculate that each one ofthem might have played a positive role in survival of thebacterium under harsh natural environments over those cells
which had fewer or no TA systems. Characterization of theseTA systems, including the identification of their cellulartargets, the mechanisms of their toxic actions and theregulatory mechanisms of their expression, therefore, isessential for our understanding of the roles of the TA
systems in bacterial physiology, pathogenicity and evolution.
Among the cellular targets for TA systems, mRNA is themost frequently used target for toxins.
MazF from E. coli cleaves mRNA at ACA sequences toeffectively inhibit protein synthesis. Since then, a large
number of MazF homologues have been identified frombacteria to archaea, and some bacteria have more than one
MazF homologues. MazF homologues so far identified
specifically cleave mRNAs at either three-, five- or
seven-base recognition sequences. It is not clear at present
why these cleavage sites consist of only odd base numbers,
but it is interesting to see how the RNA cleavage site expands

by two bases at a time from three-base sequences to fiveand to seven-base sequences. The RNA recognition andcleavage specificity appears to have been extended mostly atthe 3’ -end site, which is particularly evident when the E.
coli MazF cleavage site (A^CA or ^ACA) is compared withthe cleavage sequence of the MazF homologue (MazF-hw)
from a superhalphilic archaea, Haloquadrutum walsbyi(UU^ACUCA) 3). It seems that more space is available on
the MazF-dimer interface for RNA substrate binding, whichallows it to extend the recognition specificity at the
3’ -end4). As the recognition sequences become longer, thetarget mRNAs become more limited so that MazF
homologues cleave more and more specific mRNA species
in the cells. MazF-hw, a 7-base cutter from a coastal brine
pool on the Sinai Peninsula in Egypt seems to specificallycleaves the rhodopsin transcriptional activator as its mRNA
contains unusually as many as three of the 7-basesequences3). It should be noted that in comparison with
DNA restriction enzymes, which require a palindromic
sequence for cleavage, the number of mRNA interferases,
which may be called mRNA restriction enzymes, havepotentially so much more, since they do not require any
palindromic sequences for sequence recognition. For
example, there are only maximum 64 DNA restriction
enzymes for six-base sequences, while there are as many as
4096 (= 64 x 64) possible cleavage sites for single-stranded
six-base RNA. Although we have found a 7-base specificmRNA interferase cleaving only one out of a total of 16,384
different 7-base sequences, it remains to be elucidated how
many of 7-base specific mRNA interferases actually exists in

Stress inducible
protease

Figure 1. TA systems

nature. There could be only a few such enzymes. The cellularfunction of MazF homologues appears to be highly diverse
from those which eliminate almost all cellular mRNAs suchas ACA-specific E. coli MazF to those which are highly
sequence-specific such as, MazF-hw that eliminate only aspecific group of mRNAs in the cells3). Recently, the X-ray
structure of a UACAU-specific MazF homologue from
Bacillus subtilis forming a complex with a 9-base longun-cleavable substrate RNA 4). The X-ray structure of the
RNA-MazF complex provides insights into how a specific
RNA sequence can be recognized by MazF. On the basis of
the X-ray structure and other information, it is now possible
to explore to design MazF homologues cleaving other RNA
sequences or sequence-specific RNA binding proteins.
As mention above, the study of TA systems will open
new avenue of bacterial physiology and biotechnology.
1) Yamaguchi, Y., J. H. Park & M. Inouye, (2011) Toxin-antitoxin
systems in bacteria and archaea. Annu Rev Genet 45: 61-79.
2) Yamaguchi, Y. & M. Inouye, (2011) Regulation of growth anddeath in Escherichia coli by toxin-antitoxin systems. Nat Rev
Microbiol 9: 779-790.
3) Yamaguchi, Y., H. Nariya, J. H. Park & M. Inouye, (2012)
Inhibition of specific gene expressions by protein-mediatedmRNA interference. Nat Commun 3: 607.
4) Simanshu, D. K., Y. Yamaguchi, J. H. Park, M. Inouye & D. J.
Patel, (2013) Structural basis of mRNA recognition andcleavage by toxin MazF and its regulation by antitoxin MazE in
Bacillus subtilis. Mol Cell 52: 447-458.

■ Research Introduction
The OCU Advanced Research Institute for Natural
Science and Technology (OCARINA)
Special-appointment lecturer

Tomoyasu Noji"Glass leaf" which enables
artificial photosynthesis underaerobic condition

July/2011 Division of Material Science (Physics), Graduate
School of Science, Nagoya University Doctoral course
August/2011~March/2014 Department of Frontier
Materials, Graduate School of Engineering, Nagoya
Institute of Technology postdoctoral fellow
April/2014~January/2015 Department of Frontier
Materials, Graduate School of Engineering, Nagoya
Institute of Technology Project assistant professor
February/2015 present post

catalysts.
Leaves convert carbon dioxide and water to organic
substance and oxygen, at room temperature, atmosphericpressure, under an oxygen atmosphere with high efficiency.
A problem that is inhibited by oxygen should be overcame
to achieve the material conversion reaction (artificial
photosynthesis) under aerobic condition. A light-induced
electron transfer system combined with a photosensitizer,
an electron mediator and catalyst is required to synthesizehydrogen or as formic acid carrier of hydrogen energy bysunlight energy (Fig. 1(a)). This panel shows a standard
light-induced hydrogen production system. Photosensitizer,
electron mediator and hydrogen evolution catalyst are Ru(bpy) 3 2 + , MV 2 + and hydrogenase, respectively. Under
anaerobic condition, effectual light-induced hydrogen was
GHWHFWHG ŌLQ)LJ E 2QWKHRWKHUKDQGXQGHUDHURELF
condition, the efficiency was decrease to parts per thousand
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7KLVUHVXOWLQGLFDWHVWKDWHOHFWURQV

necessary for hydrogen evolution were deprived by oxygen
as shown red arrow in Figure 1(a). However, we have foundthat an effective hydrogen evolution reaction occurs even in
aerobic condition by introducing the light-induced hydrogen)LJ D 2YHUYLHZRIVRODUPDWHULDOFRQYHUVLRQUHDFWLRQ

evolution system in the pore of 50 nm in the porous glassand the inhibition by oxygen. (b) Light-induced hydrogenplate. Light-induced hydrogen production efficiency of

production by solar simulator. Porous glass plate systemporous glass system was increased to 3300 times of solution

under aerobic condition (ŏ). The solution system undersystem (ŏ in Fig 1 (b)). This result indicates that

DQDHURELF Ō DQGDHURELFFRQGLWLRQV ʄ  F 2YHUYLHZRI

photoreaction is faster than inflow of oxygen to inside pore

Photoreaction inside porous glass plate (pore diameter of 50(Fig. 1 (c)).

nm, thickness of 0.5 mm). The flow rate of oxygen is,Q2&$5,1$,ZDQWWRFODULI\WKHUHDFWLRQPHFKDQLVPreduced at the interface of the external solution and glassthat is specific reactions achieved inside porous glass.

nanospace. The center in the porous glass becomes low

Furthermore, I want to create a new artificial

oxygen concentration condition by photoreaction. Them, thephotosynthesis system that has an electron sourcehydrogen generation reaction is achieved. (d) Porous glass

water"glass leaf (Fig. 1 (e))" driving under an oxygen

plate immobilized Ru(bpy)32+ and MV2+&RORURJODVVZDV

atmosphere by immobilizing light-harvesting system,changed to black by accumulation of MV・+. (e) Porous glass

photosystem I, II of photosynthetic organisms and various

plate of green immobilized photosystem I.

■ Facility Introduction
Research Center for Artificial Photosynthesis Analysis Equipment<Facility Overview>Research Center for Artificial Photosynthesis(ReCAP) at OCU, established in June 2013, is a collaborative research institute equipped withanalysis equipment. The sophisticated equipment within this facility was installed for the purpose of making a significant contribution to
the vitalization of the industry through the provision of equipment and expertise, as well as advancing research within the university.
The facility is equipped with a nuclear magnetic resonance apparatus, an ion cyclotron resonance mass spectrometer, and an X-ray
diffractometer, etc. With precise and rapid analysis performed by technical staff using advanced equipment, ReCAP can respond flexibly
to the needs of users. As a shared facility, the center also provides services such as entrusted measurement, training of machine users andconsultation related to special measurement.

Nuclear magnetic resonanceapparatus
AVANCE III NMR (for liquids) with 600MHz cryoprobe(Bruker Biospin Inc.)

Features:

With extremely high mass resolution (error of 1ppm or less), thismachine only requires accurate mass number information to
identify molecular formula, making it very powerful in determining
the structures of unknown compounds. This machine includes not
only an ESI source but also the ground-breaking MALDI source,which increases the ionization rate of protein peptides. During
protein analysis it is also possible to perform primary structure
analysis (amino acid sequence analysis) by means of thefragmentation technique, using the FT-MS. This machine canconduct not only typical amino acid sequence analysis (where
proteins are identified using a database of known sequences) but
also de novo sequence analysis, which determines unknown
amino acid sequences using the mass number, obtained throughthe extremely high-precision measurement of mass.

Single Crystal X-ray Diffractometer
General Performance:(XRD, R-AXIS VII, Rigaku Corporation）

The machine determines the structure of organic compounds by
detecting the structure and state of materials by means of
nondestructive nuclear spinning. It can hasten spatial structure
analysis performed in water solutions of protein molecules.

Features:

Since the machine is equipped with a cryoprobe, it has a higher
sensitivity compared with other conventional 600MHz machines.
Spatial structure analysis of low molecular weight organic
compound solutions (molecular weight 1,000 or less) can be
performed.(However, only proteins in which substitution of carbon
cores and nitrogen cores has been conducted by means of abiochemical method, and with a molecular weight of 20,000 orless can be analyzed.)

Ion cyclotron resonance mass
spectrometer（FT-ICR-MS, MALDI, Solari X-OCU with an ESI source,
Bruker Daltonics Inc.）

General Performance: This machine accurately measures themass of ionized material to determine the atomic composition,and has the highest resolution among other mass analyzing
machines.

General Performance:

X-rays are projected from a table-top X-ray generator into the crystal
structure of the target material, and the diffracted patterns areanalyzed by the X-ray detector. Amino acid residues of the target
protein is identified and its structure is clarified at the atomic level.

Features:Protein crystal structures are measured and analyzed, using X-ray
diffraction. Since this machine can irradiate high flux X-ray beams,
the measurement of smaller crystal structures, which was difficult
using conventional machines equipped in ordinary laboratories, is
now possible. In addition, the detector reading time has been
improved, increasing measurement efficiency.

Inquiries:

Research Center for Artificial Photosynthesis(ReCAP) OfficeTel: 06-6605-3721 /e-mail: toiawase@recap.osaka-cu.ac.jp
URL: http://recap.osaka-cu.ac.jp/

OCARINA Communication 4■ Activity Report
The 2013 OCARINA Annual International Meeting
Organizer

In-house speakers

The OCU Advanced Research Institute for Natural Science andTechnology (OCARINA)

Taka-aki Asoh (Specially Appointed Lecturer, Tenure Track Project of the Advanced
Research Institute for Natural Science and Technology)
Yasuyuki Tsuboi (Professor, Advanced Research Institute for Natural Science andTechnology/ Department of Chemistry, Faculty of Science)
Masato Miyata (Professor, Advanced Research Institute for Natural Science and Technology/
Department of Biology, Faculty of Science)
Yoshikazu Nishikawa (Professor, Advanced Research Institute for Natural Science andTechnology/ Graduate School of Human Life Science)

SponsorThe OCU Strategic Key Research Project
COI-T Next Generation Hydrogen Energy Society Realization ProjectSpecial Speaker
Harue Masuda (Professor, Advanced Research Institute for Natural Scienceand Technology / Department of Geosciences, Faculty of Science, OCU)

Guest Speakers
Tim Storr (CA/ Associate Professor, Simon Fraser University)
Rudi Berera (NL/ PD, Vrije Universiteit Amsterdam)
Yasushi Nishihara(Professor, Department of Chemistry, Faculty of Science, Okayama University)

Masaki Ihara(Assistant Professor, Project Research Promotion Center, Faculty of Agriculture, Shinshu
University)

Ryutaro Tokutsu(Assistant Professor, Division of Environmental Photobiology, National Institute for Basic
Biology)
Yasuhiro Funabashi (Professor, Graduate School of Science, Osaka University)

13

The 2013 OCARINA Annual International Meeting was held in the Osaka City University Media Center on
the 4th and 5th of March, 2014.
The Advanced Research Institute for Natural Science and Technology has held annual meetings regularly
since 2008, and this was the fifth international symposium. Harue Masuda, a professor from OCU, presented
her research report on the mechanism of arsenic pollution as a special lecture, and six other guest speakers(two from overseas) and four in-house speakers gave presentations on their research reports from various
fields.
At the student poster presentation, 30 posters were presented during the tight schedule of the symposium.
The meeting finished a success.

The 1st Osaka City University Tenure Track Teachers Research Presentation Event

Date: Wednesday, December 3, 2014 Venue: Osaka City University Media Center
Presenters: The collaborative graduate school is shown in〈〉
Satoshi Endo

(Specially Appointed Associate Professor,Tenure
Track Project of the Urban Research Plaza)

Yoshihiro Yamaguchi

Institute for Natural Science and Technology)<Graduate School of Engineering >Taka-aki Asoh (Specially Appointed Lecturer, Tenure
Track Project of the Advanced Research Institute

Cai Kai(Specially Appointed Associate Professor,
Tenure Track Project of the Advanced Research<Graduate School of Science >Eriko Nagadai

for Natural Science and Technology)(Specially Appointed Associate Professor,
Tenure Track Project of the Advanced Research<Graduate School of Science >Institute for Natural Science and Technology)(Specially Appointed Associate Professor, Tenure
Track Project of the Urban Research Plaza)<Graduate School of Human Life Science ><Graduate School of Engineering >The OCU Advance Research Institute for Natural Science and TechOCARINA Communication 4

OCARINA Seminars
The Advanced Research Institute invites leading scientists from Japan and abroad to its occasional OCARINA seminars. In
addition to the regular seminars, guests are also invited to a series of major seminars known as “DISCO Parties” (see note*).
Also convened as OCARINA seminars, with students forming the main constituent, DISCO Parties provide a common place
for people with various occupations, including teaching staff, to discuss students’ research

17th

Date

February 3rd, 2014

Guest

Jitendra K. Bera（Professor, Indian Institute of Technology Kanpur）

Theme Bifunctionality in Organometallic Catalysis
DISCO Party major seminar No. 7

18thStudent：Keisuke Kawamoto (OCU Kinoshita Laboratory D2)

Date

June 18, 2014

Guest

Yuzuru Yoneda（Professor, Radiocarbon Dating Laboratory, The University Museum of the University of Tokyo）

Venue Building 2, 220A

Theme Human evolution from the viewpoint of the ecology of eating
DISCO Party major seminar No. 8

19thVenue Faculty of Science Conference RoomStudent：Shusaku Ikeyama（OCU Amao Laboratory D1）Venue Building 2, 220B

Date

September 19, 2014

Guest

Kentaro Ifuku (Assistant Professor, Laboratory of Molecular and Cellular Biology of Totipotency, Graduate School of Biostudies, Kyoto University）

Theme Development of foundation technology for the production of diatom in biofactories

20th

Date

September 22, 2014

Guest

Makiko Kosugi (Specially Appointed Staff of the National Institute of Polar Research, Research
Assistant in the Department of Biological Sciences, Faculty of Science and Engineering, Chuo University）

Venue Building 2, 220A

Theme Ecological study of photosynthetic organisms living on the bedrock outcrop in the vicinity of Showa Station in Antarctic

21st

Date

November 19, 2014

Venue Building 2, 220B

Guest

Nicholas Cox (Ph.D, Group leader, Max Planck Institute for Chemical Energy Conversion, Germany)

Theme The reaction mechanism of water decomposition and oxygen evolution based on recent
analysis using the photosystem II electron spin resonance method
See the website for details.

* Doctor Course students’ Incorporated Scientific Communication (DISCO) Party:
A group of doctoral students affiliated with OCARINA organizes a weekly closed mini seminar just for students, to serve as an opportunity to deepen
their understanding of each other’s work and promote mutual development. In addition to this, a major seminar is held several times a year.

The first Osaka City University (OCU) Tenure-track Staff
Research Presentation Event was held in the OCU Media
Center on 3rd of December, 2014, in which five tenure-track
staff who were selected through the public appeal madepresentations on their research and received advice frominvited domestic specialists in each field. This event wasorganized to provide an opportunity for young staff todevelop their research by receiving comments from
specialists. Three tenure-track staff members fromOCARINA made presentations.
Michio Miyano, Vice president of OCU, made an opening
address and introduced activities for the promotion anddevelopment of the tenure-track project. Presenters wereencouraged through warm support and constructive
criticism, and lively specialist discussions were conducted.
Isamu Kinoshita, Director of OCARINA, made a closing
address giving his encouragement and expectations for
future activities, and a social gathering was held.
The Media Center was almost filled to capacity, with 73
attendants from in-house and other facilities attending.
The OCU Advance Research Institute for Natural Science and Tech

14

OCARINA Communication 4

History of the Osaka City University Advanced Research Institute2008 March
April
December2010 March
March

OctoberNovember
December
2011 March2012 March
April
July
2013 March
April
June

2014 February
February
March
March
April

Founding Anniversary International Symposium held
The OCU strategic key research project (2008-2011) started
International Workshop held on the eﬃcient use of sunlight energy
1st International symposium held
Enforcement of oﬃcial regulations (start of activities as an oﬃcial bureau)
Building 2 renovated for research ﬂoors of OCARINA
Opening symposium for building 2 of OCARINA held
2nd International symposium held
3rd International symposium, “Kakuno memorial,” held
Annual meeting and the OCU strategic key research project(2008-2011) debrieﬁng held
The OCU strategic key research project (2012-2014) started School of
Science Building C completed, partial occupation
4th International symposium held
2 new full-time staﬀ members appointed
Research Center of Artiﬁcial Photosynthesis opened
Partial occupation for the new School of Science Building
One new full-time tenure track staﬀ member appointed
One new full-time tenure track staﬀ member appointed
5th International symposium held
The ﬁrst Osaka City University Tenure Track Teachers Research Presentation Event

Osaka City University Advanced Research Institutefor Natural Science and Technology
3-3-138 Sugimoto, Sumiyoshi-ku,
Osaka 558-8585, Japan
http://www.ocarina.osaka-cu.ac.jp/

Midosuji sub.

JR Shinkansen

Shin-Osaka

to Shin-Kobe

JR Kobe line

Osaka

to Shin-Kobe
JR Tozai line

KyobashiTsuruhasi

OSAKA-loop line

Tennoji
Abiko

Sugimoto-cho

Sugimoto
Campus (OCARINA)
Kansai Airport

Hineno
JR Hanwa line
The OCU Advance Research Institute for Natural Science and Tech