Research Laboratories
MOLECULAR GENETICS (Shigeki Ehira, Ryudo Ohbayashi)
Research Overview
Humans still do not understand everything that happens inside the cells, even for simple organisms such as Escherichia coli. There are also many things that we don't understand about the various mechanisms in cyanobacteria, which is the established prototype for photosynthetic organisms. Using bacteria as our model, we study various genes with the goal of thoroughly understanding the universal processes of life, such as growth, survival, and cell differentiation at the molecular level. We are specifically interested in exploring the mechanisms that drive the occurrence of environmental adaptations in microorganisms by utilizing cyanobacteria as our primary model organism
Cyanobacteria are unique in microorganisms in that they perform oxygenic photosynthesis like plants. Being thought to have emerged approximately 2.5billion years ago, they have successfully colonized many different environments and are now widespread where there is light and water. They inhabit diverse ecosystems, from lakes and oceans to terrestrial habitats, even including extreme environments such as glaciers, hot springs, and deserts. Our research aims to unravel the systems that enable cyanobacteria to perform their unique functions and thrive under such harsh conditions.
To this end, we employ many techniques in molecular biology that target DNA, RNA, and proteins, omics approaches like transcriptome analysis, and synthetic biology methods to manipulate gene functions with precision.
Research in our laboratory include the following themes:
- Mechanisms of adaptation to extreme environments
- Regulatory mechanisms involved in the formation of differentiated cells with unique adaptations
- Biosynthesis of useful products from carbon dioxide using cyanobacteria
If you are interested in joining the graduate program and doing research with us, please contact us through email.
Current Projects
(1) Mechanisms of adaptation to extreme environments
Certain cyanobacteria thrive in extreme environments like desserts and glaciers where few organisms can even exist. In order to uncover how they can survive drought and freezing conditions, we are working to identify and analyze genes related to these tolerances. Our goal is to understand the adaptations of these microorganisms in order to gain insight into the adaptations of organisms at the genetic level
(2) Regulatory mechanisms involved in the formation of differentiated cells with unique adaptations
Cyanobacteria exhibit a range of forms from unicellular to morphologically complex multicellular ones. Some multicellular cyanobacteria generate specialized cells that allow them to survive harsh conditions, thrive in nutrient-poor environments, and form symbiotic relationships with other organisms like plants. These specialized cells have only been observed to form when conditions are difficult, and so our research aims to understand how the cyanobacteria sense environmental changes and how they get triggered to produce cells with specialized functions.
(3) Biosynthesis of useful products from carbon dioxide using cyanobacteria
From their photosynthetic activity, cyanobacteria can produce different substances from carbon dioxide and light energy. This make them attractive as potential hosts for biofuel and bioplastic production. Our goal in this regard is to engineer new cells that exclusively produce substances using heterocyst, which are differentiated cells of multicellular cyanobacteria. Heterocysts are cells that can only perform nitrogen fixation, a process that converts atmospheric nitrogen into ammonia that is more bioavailable and can be utilized by other organisms. In the cyanobacteria, these heterocysts provide the ammonia to adjacent cells for amino acid synthesis necessary for growth. Since heterocysts do not grow or divide, they act as continous factories of amino acid building blocks. We aim to take advantage of these characteristics to create a biosynthetic system for producing valuable products. Moreover, we are working on producing nitrogen-containing compounds (e.g. diamines used in nylon production) from atmospheric CO2 and N2 by utilizing the cyanobacteria's ability for both carbon dioxide and nitrogen fixation.
Staff Highlight
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Dr. Shigeki Ehira (得平 茂樹) Professor | Dr. Ryudo Ohbayashi (大林 龍胆) Associate Professor |
Email: | |
ehira[at]tmu.ac.jp | ryudohbys[at]tmu.ac.jp |
| Read more: | |
Lab Information: | |
Recent Publications
Yuichi Kato, Kouhei Kamasaka, Mami Matsuda, Hiroko Koizumi, Ryudo Ohbayashi, Hiroki Ashida, Akihiko Kondo,
Tomohisa Hasunuma. Journal of Bioscience and Bioengineering, (in press), Dec 2024
2. Strong interaction of CpcL with photosystem I cores induced in heterocysts of Anabaena sp. PCC 7120
Takehiro Suzuki, Haruya Ogawa, Naoshi Dohmae, Jian-Ren Shen, Shigeki Ehira, Ryo Nagao, microPublication Biology,
May 2024
Yuichi Kato, Ryota Hidese, Mami Matsuda, Ryudo Ohbayashi, Hiroki Ashida, Akihiko Kondo, Tomohisa Hasunuma
Communications Biology, 7(1) 233-233, Feb 2024
Kazuma Ohdate, Minori Sakata, Kaisei Maeda, Yutaka Sakamaki, Kaori Nimura-Matsune, Ryudo Ohbayashi, Wolfgang R. Hess,
Satoru Watanabe, Frontiers in Microbiology, 15, Feb 2024
Atsuko Hishida, Ryo Shirai, Akiyoshi Higo, Minenosuke Matsutani, Kaori Nimura-Matsune, Tomoko Takahashi,
Satoru Watanabe, Shigeki Ehira, Yukako Hihara. The Journal of General and Applied Microbiology, 70(1) 2024.01.001, Jan 2024
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