研究者紹介システム

加藤 悠一
カトウ ユウイチ
先端バイオ工学研究センター
助教
生物関係
Last Updated :2022/08/04

研究者情報

所属

  • 【主配置】

    先端バイオ工学研究センター

学位

  • 博士(理学), 京都大学

研究ニュース

研究活動

研究分野

  • ライフサイエンス / 水圏生命科学
  • ライフサイエンス / 応用微生物学

論文

  • Kosuke Inabe, Ayaka Miichi, Mami Matsuda, Takanobu Yoshida, Yuichi Kato, Ryota Hidese, Akihiko Kondo, Tomohisa Hasunuma

    Nitrogen is essential for the biosynthesis of various molecules in cells, such as amino acids and nucleotides, as well as several types of lipids and sugars. Cyanobacteria can assimilate several forms of nitrogen, including nitrate, ammonium, and urea, and the physiological and genetic responses to these nitrogen sources have been studied previously. However, the metabolic changes in cyanobacteria caused by different nitrogen sources have not yet been characterized. This study aimed to elucidate the influence of nitrate and ammonium on the metabolic profiles of the cyanobacterium Synechocystis sp. strain PCC 6803. When supplemented with NaNO3 or NH4Cl as the nitrogen source, Synechocystis sp. PCC 6803 grew faster in NH4Cl medium than in NaNO3 medium. Metabolome analysis indicated that some metabolites in the CBB cycle, glycolysis, and TCA cycle, and amino acids were more abundant when grown in NH4Cl medium than NaNO3 medium. 15N turnover rate analysis revealed that the nitrogen assimilation rate in NH4Cl medium was higher than in NaNO3 medium. These results indicate that the mechanism of nitrogen assimilation in the GS-GOGAT cycle differs between NaNO3 and NH4Cl. We conclude that the amounts and biosynthetic rate of cyanobacterial metabolites varies depending on the type of nitrogen.

    MDPI AG, 2021年12月14日, Metabolites, 11 (12), 867 - 867, 英語, 国際誌

    研究論文(学術雑誌)

  • Yuichi Kato, Tomoki Oyama, Kentaro Inokuma, Christopher J. Vavricka, Mami Matsuda, Ryota Hidese, Katsuya Satoh, Yutaka Oono, Jo-Shu Chang, Tomohisa Hasunuma, Akihiko Kondo

    AbstractLight/dark cycling is an inherent condition of outdoor microalgae cultivation, but is often unfavorable for lipid accumulation. This study aims to identify promising targets for metabolic engineering of improved lipid accumulation under outdoor conditions. Consequently, the lipid-rich mutant Chlamydomonas sp. KOR1 was developed through light/dark-conditioned screening. During dark periods with depressed CO2 fixation, KOR1 shows rapid carbohydrate degradation together with increased lipid and carotenoid contents. KOR1 was subsequently characterized with extensive mutation of the ISA1 gene encoding a starch debranching enzyme (DBE). Dynamic time-course profiling and metabolomics reveal dramatic changes in KOR1 metabolism throughout light/dark cycles. During light periods, increased flux from CO2 through glycolytic intermediates is directly observed to accompany enhanced formation of small starch-like particles, which are then efficiently repartitioned in the next dark cycle. This study demonstrates that disruption of DBE can improve biofuel production under light/dark conditions, through accelerated carbohydrate repartitioning into lipid and carotenoid.

    Springer Science and Business Media LLC, 2021年12月, Communications Biology, 4 (1), 450 - 450, 英語, 国際誌

    研究論文(学術雑誌)

  • Yuichi Kato, Kosuke Inabe, Ryota Hidese, Akihiko Kondo, Tomohisa Hasunuma

    Metabolomics, an essential tool in modern synthetic biology based on the design-build-test-learn platform, is useful for obtaining a detailed understanding of cellular metabolic mechanisms through comprehensive analyses of the metabolite pool size and its dynamic changes. Metabolomics is critical to the design of a rational metabolic engineering strategy by determining the rate-limiting reaction and assimilated carbon distribution in a biosynthetic pathway of interest. Microalgae and cyanobacteria are promising photosynthetic producers of biofuels and bio-based chemicals, with high potential for developing a bioeconomic society through bio-based carbon neutral manufacturing. Metabolomics technologies optimized for photosynthetic organisms have been developed and utilized in various microalgal and cyanobacterial species. This review provides a concise overview of recent achievements in photosynthetic metabolomics, emphasizing the importance of microalgal and cyanobacterial cell factories that satisfy industrial requirements.

    Elsevier BV, 2021年10月25日, Bioresource technology, 344 (Pt A), 126196 - 126196, 英語, 国際誌

    研究論文(学術雑誌)

  • Jih-Heng Chen, Yuichi Kato, Mami Matsuda, Chun-Yen Chen, Dillirani Nagarajan, Tomohisa Hasunuma, Akihiko Kondo, Jo-Shu Chang

    Microalgae-derived carotenoids have increasingly been considered as feasible green alternatives for synthetic antioxidants. In this study, the lutein high-yielding strain (Chlorella sorokiniana MB-1; henceforth MB-1) and its mutant derivative (C. sorokiniana MB-1-M12; henceforth M12) were evaluated for their growth, biomass production, and lutein accumulation in three different cultivation modes - photoautotrophy, mixotrophy, and heterotrophy. M12 could grow effectively under heterotrophic conditions, but the lutein content was lower, indicating the necessity of photo-induction for lutein accumulation. Metabolic analysis of MB-1 and M12 in autotrophic growth in the presence of carbon dioxide indicated that carbon assimilation and channeling of the fixed metabolites towards carotenoid accumulation was elevated in M12 compared to MB-1. Novel two-stage alternative cultivation strategies (Autotrophic/Heterotrophic and Mixotrophic/Heterotrophic cultures) were applied for enhancing lutein production in M12. Maximum lutein quantity (6.17 mg/g) and production (33.64 mg/L) were obtained with the TSHM strategy that is considered the best two-stage operation.

    Elsevier BV, 2021年08月, Bioresource Technology, 334, 125200 - 125200, 英語, 国際誌

    研究論文(学術雑誌)

  • Nao Nitta, Takanori Iino, Akihiro Isozaki, Mai Yamagishi, Yasutaka Kitahama, Shinya Sakuma, Yuta Suzuki, Hiroshi Tezuka, Minoru Oikawa, Fumihito Arai, Takuya Asai, Dinghuan Deng, Hideya Fukuzawa, Misa Hase, Tomohisa Hasunuma, Takeshi Hayakawa, Kei Hiraki, Kotaro Hiramatsu, Yu Hoshino, Mary Inaba, Yuki Inoue, Takuro Ito, Masataka Kajikawa, Hiroshi Karakawa, Yusuke Kasai, Yuichi Kato, Hirofumi Kobayashi, Cheng Lei, Satoshi Matsusaka, Hideharu Mikami, Atsuhiro Nakagawa, Keiji Numata, Tadataka Ota, Takeichiro Sekiya, Kiyotaka Shiba, Yoshitaka Shirasaki, Nobutake Suzuki, Shunji Tanaka, Shunnosuke Ueno, Hiroshi Watarai, Takashi Yamano, Masayuki Yazawa, Yusuke Yonamine, Dino Di Carlo, Yoichiroh Hosokawa, Sotaro Uemura, Takeaki Sugimura, Yasuyuki Ozeki, Keisuke Goda

    The advent of image-activated cell sorting and imaging-based cell picking has advanced our knowledge and exploitation of biological systems in the last decade. Unfortunately, they generally rely on fluorescent labeling for cellular phenotyping, an indirect measure of the molecular landscape in the cell, which has critical limitations. Here we demonstrate Raman image-activated cell sorting by directly probing chemically specific intracellular molecular vibrations via ultrafast multicolor stimulated Raman scattering (SRS) microscopy for cellular phenotyping. Specifically, the technology enables real-time SRS-image-based sorting of single live cells with a throughput of up to ~100 events per second without the need for fluorescent labeling. To show the broad utility of the technology, we show its applicability to diverse cell types and sizes. The technology is highly versatile and holds promise for numerous applications that are previously difficult or undesirable with fluorescence-based technologies.

    Springer Science and Business Media LLC, 2020年12月, Nature Communications, 11 (1), 3452 - 3452, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • A. Isozaki, Y. Nakagawa, M. H. Loo, Y. Shibata, N. Tanaka, D. L. Setyaningrum, J.-W. Park, Y. Shirasaki, H. Mikami, D. Huang, H. Tsoi, C. T. Riche, T. Ota, H. Miwa, Y. Kanda, T. Ito, K. Yamada, O. Iwata, K. Suzuki, S. Ohnuki, Y. Ohya, Y. Kato, T. Hasunuma, S. Matsusaka, M. Yamagishi, M. Yazawa, S. Uemura, K. Nagasawa, H. Watarai, D. Di Carlo, K. Goda

    Droplet microfluidics has become a powerful tool in precision medicine, green biotechnology, and cell therapy for single-cell analysis and selection by virtue of its ability to effectively confine cells. However, there remains a fundamental trade-off between droplet volume and sorting throughput, limiting the advantages of droplet microfluidics to small droplets (<10 pl) that are incompatible with long-term maintenance and growth of most cells. We present a sequentially addressable dielectrophoretic array (SADA) sorter to overcome this problem. The SADA sorter uses an on-chip array of electrodes activated and deactivated in a sequence synchronized to the speed and position of a passing target droplet to deliver an accumulated dielectrophoretic force and gently pull it in the direction of sorting in a high-speed flow. We use it to demonstrate large-droplet sorting with ~20-fold higher throughputs than conventional techniques and apply it to long-term single-cell analysis of Saccharomyces cerevisiae based on their growth rate.

    American Association for the Advancement of Science (AAAS), 2020年05月, Science Advances, 6 (22), eaba6712 - eaba6712, 英語

    [査読有り]

    研究論文(学術雑誌)

  • Hasunuma T, Takaki A, Matsuda M, Kato Y, Vavricka CJ, Kondo A

    The natural pigment astaxanthin is widely used in aquaculture, pharmaceutical, nutraceutical, and cosmetic industries due to superior antioxidant properties. The green alga Haematococcus pluvialis is currently used for commercial production of astaxanthin pigment. However, slow growing H. pluvialis requires a complex two-stage stress-induced process with high light intensity leading to increased contamination risks. In contrast, the fast-growing euryhaline cyanobacterium Synechococcus sp. PCC 7002 (Synechococcus 7002) is able to reach high density under stress-free phototrophic conditions, and is therefore a promising metabolic engineering platform for astaxanthin production. In the present study, genes encoding β-carotene hydroxylase and β-carotene ketolase, from the marine bacterium Brevundimonas sp. SD212, are integrated into the endogenous plasmid of Synechococcus 7002, and then expressed to biosynthesize astaxanthin. Although Synechococcus 7002 does not inherently produce astaxanthin, the recombinant ZW strain yields 3 mg/g dry cell weight astaxanthin from CO2 as the sole carbon source, with significantly higher astaxanthin content than previous cyanobacteria reports. Synechococcus 7002 astaxanthin productivity reached 3.35 mg/L/day after just 2 days in a continuous autotrophic process, which is comparable to the best H. pluvialis astaxanthin productivities when factoring in growth times. Metabolomics analysis reveals increases in fractions of hexose-, pentose-, and triose phosphates along with intermediates involved in the nonmevalonate pathway. Dynamic metabolomics analysis of 13C labeled metabolites clearly indicates flux enhancements in the Calvin cycle and glycolysis resulting from the overexpression of astaxanthin biosynthetic genes. This study suggests that cyanobacteria may enhance central metabolism as well as the nonmevalonate pathway in an attempt to replenish depleted pigments such as β-carotene and zeaxanthin.

    2019年11月, ACS synthetic biology, 8 (12), 2701 - 2709, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Chen JH, Kato Y, Matsuda M, Chen CY, Nagarajan D, Hasunuma T, Kondo A, Dong CD, Lee DJ, Chang JS

    In this study, microalgal cultivation was applied as a feasible strategy for treating shrimp culture wastewater (SCW) from a shrimp farm in southern Tainan. Chlorella sorokiniana MB-1-M12 was first grown on BG-11 medium with 0.5% salinity, obtaining a biomass concentration and productivity of 4.35 g/L and 1.56 g/L/d, respectively. When 80% of BG-11 nutrients were added to 75% strength SCW, lutein content and productivity increased to 5.19 mg/g and 5.55 mg/L/d, respectively. A novel operation strategy involving periodic exchange of freshwater and SCW was designed for semi-continuous cultivation of MB-1-M12 strain for optimal biomass and lutein production. The average biomass concentration, productivity, lutein content, and productivity were 3.5 g/L, 1.3 g/L/d, 3.89 mg/g and 5.0 mg/L/d, respectively. Although microalgae have been considered as an alternative natural source of lutein, this work is among the earliest reports describing lutein production from microalgae cultivated with wastewater via a circular economy concept.

    2019年10月, Bioresource technology, 290, 121786 - 121786, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Kento IGARASHI, Masafumi FUNAKOSHI, Seiji KATO, Takahito MORIWAKI, Yuichi KATO, Qiu-Mei ZHANG-AKIYAMA

    Apurinic/apyrimidinic (AP) sites are the most common form of cytotoxic DNA damage. Since AP sites inhibit DNA replication and transcription, repairing them is critical for cell growth. However, the significance of repairing AP sites during early embryonic development has not yet been clearly determined. Here, we focused on APEX1 from the ascidian Ciona intestinalis (CiApex1), a homolog of human AP endonuclease 1 (APEX1), and examined its role in early embryonic development. Recombinant CiApex1 protein complemented the drug sensitivities of an AP endonuclease-deficient Escherichia coli mutant, and exhibited Mg2+-dependent AP endonuclease activity, like human APEX1, in vitro. Next, the effects of abnormal AP site repair on embryonic development were investigated. Treatment with methyl methanesulfonate, which alkylates DNA bases and generates AP sites, induced abnormal embryonic development. This abnormal phenotype was also caused by treatment with methoxyamine, which inhibits AP endonuclease activity. Furthermore, we constructed dominant-negative CiApex1, which inhibits CiApex1 action, and found that its expression impaired embryonic growth. These results suggested that AP site repair is essential for embryonic development and CiApex1 plays an important role in AP site repair during early embryonic development in C. intestinalis.

    Genetics Society of Japan, 2019年04月, Genes & Genetic Systems, 94 (2), 81 - 93, 英語, 国内誌

    [査読有り]

    研究論文(学術雑誌)

  • Kato Y, Fujihara Y, Vavricka CJ, Chang JS, Hasunuma T, Kondo A

    BACKGROUND: Light/dark cycling is an inevitable outdoor culture condition for microalgal biofuel production; however, the influence of this cycling on cellular lipid production has not been clearly established. The general aim of this study was to determine the influence of light/dark cycling on microalgal biomass production and lipid accumulation. To achieve this goal, specific causative mechanisms were investigated using a metabolomics approach. Laboratory scale photoautotrophic cultivations of the oleaginous green microalga Chlamydomonas sp. JSC4 were performed under continuous light (LL) and light/dark (LD) conditions. RESULTS: Lipid accumulation and carbohydrate degradation were delayed under the LD condition compared with that under the LL condition. Metabolomic analysis revealed accumulation of phosphoenolpyruvate and decrease of glycerol 3-phosphate under the LD condition, suggesting that the imbalance of these metabolites is a source of delayed lipid accumulation. When accounting for light dosage, biomass yield under the LD condition was significantly higher than that under the LL condition. Dynamic metabolic profiling showed higher levels of lipid/carbohydrate anabolism (including production of 3-phosphoglycerate, fructose 6-phosphate, glucose 6-phosphate, phosphoenolpyruvate and acetyl-CoA) from CO2 under the LD condition, indicating higher CO2 fixation than that of the LL condition. CONCLUSIONS: Photoperiods define lipid accumulation and biomass production, and light/dark cycling was determined as a critical obstacle for lipid production in JSC4. Conversions of phosphoenolpyruvate to pyruvate and 3-phosphoglycerate to glycerol 3-phosphate are the candidate rate-limiting steps responsible for delayed lipid accumulation. The accumulation of substrates including ribulose 5-phosphate could be explained by the close relationship of increased biomass yield with enhanced CO2 fixation. The present study investigated the influence of light/dark cycling on lipid production by direct comparison with continuous illumination for the first time, and revealed underlying metabolic mechanisms and candidate metabolic rate-limiting steps during light/dark cycling. These findings suggest promising targets to metabolically engineer improved lipid production.

    2019年02月, Biotechnology for biofuels, 12, 39 - 39, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Tomohisa Hasunuma, Mami Matsuda, Yuichi Kato, Christopher John Vavricka, Akihiko Kondo

    Succinate is a versatile petrochemical compound that can be produced by microorganisms, often from carbohydrate based carbon sources. Phototrophic cyanobacteria including Synechocystis sp. PCC 6803 can more efficiently produce organic acids such as succinate without sugar supplementation, via photosynthetic production of glycogen followed by glycogen utilization, typically under dark conditions. In this study, Synechocystis 6803 bioproduction of organic acids under dark anoxic conditions was found to increase with elevation of temperature from 30 °C to 37 °C. The further enhancement of succinate bioproduction by overexpression of the rate limiting enzyme phosphoenolpyruvate carboxylase resulted in improved glycogen utilization. To gain more insight into the mechanisms underlying the increased organic acid output, a novel temperature dependent metabolomics analysis was performed. Adenylate energy charge was found to decrease along with elevating temperature, while central metabolites glucose 6-phosphate, fructose 6-phosphate, fructose 1,6-bisphosphate, glycerol 3-phosphate, malate, fumarate and succinate increased. Temperature dependent 13C-labeling metabolomics analysis further revealed a glycolysis to TCA bottleneck, which could be overcome by addition of CO2, leading to even higher organic acid production. Optimization of initial cell concentration to 25 g-dry cell weight/L, in combination with 100 mM NaHCO3 supplementation, afforded a succinate titer of over 1.8 g/L, the highest reported autotrophic succinate titer. Succinate titers remained high after additional knockout of ackA, resulting in the highest reported autotrophic D-lactate titer as well. The optimization of Synechocystis 6803 organic acid production therefore holds significant promise for CO2 capture and utilization.

    Academic Press Inc., 2018年07月01日, Metabolic Engineering, 48, 109 - 120, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Yuichi Kato, Shih-Hsin Ho, Christopher J. Vavricka, Jo-Shu Chang, Tomohisa Hasunuma, Akihiko Kondo

    The aim of this study was to improve biomass production of the green microalga Chlamydomonas sp. JSC4 under high salinity conditions. For this purpose, heavy ion beam-coupled mutagenesis and evolutionary engineering were performed using JSC4 as the parent strain. After long-term and continuous cultivation with high salinity, salt-resistant strains that grow well even in the presence of 7% sea salt were successfully obtained. Transcriptional analysis revealed inactivation of starch-to-lipid biosynthesis switching, which resulted in delayed starch degradation and decreased lipid content in the salt-resistant strains. Cellular aggregation and hypertrophy during high salinity were relieved in these strains, indicating strong resistance to salt stress. These results suggest that high salinity stress, not the salinity condition itself, is important for activating lipid accumulation mechanisms in microalgae. (C) 2017 Elsevier Ltd. All rights reserved.

    ELSEVIER SCI LTD, 2017年12月, BIORESOURCE TECHNOLOGY, 245 (part B), 1484 - 1490, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Shih-Hsin Ho, Akihito Nakanishi, Yuichi Kato, Hiroaki Yamasaki, Jo-Shu Chang, Naomi Misawa, Yuu Hirose, Jun Minagawa, Tomohisa Hasunuma, Akihiko Kondo

    Biodiesel production using microalgae would play a pivotal role in satisfying future global energy demands. Understanding of lipid metabolism in microalgae is important to isolate oleaginous strain capable of overproducing lipids. It has been reported that reducing starch biosynthesis can enhance lipid accumulation. However, the metabolic mechanism controlling carbon partitioning from starch to lipids in microalgae remains unclear, thus complicating the genetic engineering of algal strains. We here used "dynamic" metabolic profiling and essential transcription analysis of the oleaginous green alga Chlamydomonas sp. JSC4 for the first time to demonstrate the switching mechanisms from starch to lipid synthesis using salinity as a regulator, and identified the metabolic rate-limiting step for enhancing lipid accumulation (e. g., pyruvate-to-acetyl-CoA). These results, showing salinity-induced starch-tolipid biosynthesis, will help increase our understanding of dynamic carbon partitioning in oleaginous microalgae. Moreover, we successfully determined the changes of several key lipid-synthesis- related genes (e. g., acetyl-CoA carboxylase, pyruvate decarboxylase, acetaldehyde dehydrogenase, acetylCoA synthetase and pyruvate ferredoxin oxidoreductase) and starch-degradation related genes (e. g., starch phosphorylases), which could provide a breakthrough in the marine microalgal production of biodiesel.

    NATURE PUBLISHING GROUP, 2017年04月, SCIENTIFIC REPORTS, 7 (7), 45471 - 45471, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Yuichi Kato, Masahiro Miyaji, Qiu-Mei Zhang-Akiyama

    The anticancer drug 5-fluorouracil (5-FU) and its metabolite 5-fluoro-2'-deoxyuridine (FUdR) inhibit thymidylate synthase and induce uracil bases in DNA. FUdR is commonly used for inhibiting fertility when measuring the life-span of the nematode Caenorhabditis elegans. However, it is not known whether DNA damage induced by FUdR affects lifespan. EXO-3 is an apurinic/apyrimidinic endonuclease in C. elegans, and we reported previously that deletion of the exo-3 gene causes reproductive abnormalities and decreased lifespan. In this study, we found that FUdR extended the lifespan of exo-3 mutants. We measured the lifespan of multiple germline mutants to examine whether this lifespan extension effect was dependent on fertility. In the presence of a fern-1 mutation, which causes a deficiency in sperm production, FUdR did not extend the lifespan of the exo-3 mutant. In glp-1 mutants, which do not develop gonads, the exo-3 mutant was not short-lived, and FUdR did not extend its lifespan. These results suggest that the lifespan extension effect of FUdR depends on fertility and the presence of gonads. fern-3 mutants, which do not produce oocytes, had increased lifespan in the presence of FUdR, independent of the exo-3 mutation. It is possible that the fern-3 mutant was susceptible to the lifespan extension effect of FUdR. From these results, we suggest that FUdR affects the lifespan of C. elegans in two ways: by interfering with fertility, which extends lifespan, and by inducing DNA base damage, which reduces lifespan.

    GENETICS SOC JAPAN, 2016年08月, GENES & GENETIC SYSTEMS, 91 (4), 201 - 207, 英語, 国内誌

    [査読有り]

    研究論文(学術雑誌)

  • Takahito MORIWAKI, Yuichi KATO, Chihiro NAKAMURA, Satoru ISHIKAWA, Qiu-Mei ZHANG-AKIYAMA

    DNA mismatch repair (MMR) contributes to genome integrity by correcting errors of DNA polymerase and inducing cell death in response to DNA damage. Dysfunction of MMR results in increased mutation frequency and cancer risk. Clinical researches revealed that MMR abnormalities induce cancers of non-dividing tissues, such as kidney and liver. However, how MMR suppresses cancer in non-dividing tissues is not understood. To address that mechanism, we analyzed the roles of MMR in non-dividing cells using Caenorhabditis elegans (C. elegans), in which all somatic cells are non-dividing in the adult stage. In this study, we used stable MMR-mutant lines with a balancer chromosome. First, we confirmed that deficiency of MMR leads to resistance to various mutagens in C. elegans dividing cells. Next, we performed drug resistance assays, and found that MMR-deficient adult worms were resistant to SN1-type alkylating and oxidizing agents. In addition, dead cell staining and reporter assays of an autophagy-related gene demonstrated that the cell death was autophagic cell death. Interestingly, this autophagic cell death was not suppressed by caffeine, implying that MMR induces death of non-dividing cells in an atl-1-independent manner. Hence, we propose the hypothesis that MMR prevents cancers in non-dividing tissues by directly inducing cell death.

    2015年07月, Genes & Cancer, 6 (7-8), 341 - 355, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Yuichi Kato, Takahito Moriwaki, Masafumi Funakoshi, Qiu-Mei Zhang-Akiyama

    Apurinic/apyrimidinic (AP) sites are the major DNA damage generated continuously even under normal conditions, and inhibit DNA replication/transcription. AP endonucleases are ubiquitous enzymes required for the repair of AP sites and 3' blocking ends, but their physiological roles in multicellular organisms are not fully understood. In this study, we investigated how an AP endonuclease functions in a multicellular organism (Caenorhabditis elegans (C. elegans)). EXO-3 is one of the AP endonucleases in C. elegans. Using an exo-3 mutant worm, we found that deletion of the exo-3 gene caused shortened lifespan in an ung-1-dependent manner. UNG-1 is a uracil DNA glycosylase in C elegans, and the present finding suggested that UNG-1 is the major producer of AP sites that affects lifespan, and EXO-3 contributes to longevity by completing the repair of uracil. Next we found that the exo-3 gene was abundantly expressed in the gonads, and AP sites in the gonad were efficiently repaired, suggesting that EXO-3 functioned particularly in the gonad. Deletion of the exo-3 gene resulted in a significant decrease in self-brood size. This was rescued by deficiency of NTH-1, which is a bifunctional DNA glycosylase in C. elegans that recognizes oxidative base damage. This result suggested that the major substrate of EXO-3 in the gonad was 3' blocking end generated by NTH-1, and that EXO-3 played an important role in reproduction. A contribution of EXO-3 to reproduction was also suggested by our finding here that the decrease of self-brood size of the exo-3 mutant became more marked when worms were treated with methyl methanesulfonate (MMS) and sodium bisulfite (NaHSO3). This study demonstrated differential roles of EXO-3 in somatic cells and germ cells. (C) 2015 Elsevier B.V. All rights reserved.

    ELSEVIER SCIENCE BV, 2015年02月, MUTATION RESEARCH-FUNDAMENTAL AND MOLECULAR MECHANISMS OF MUTAGENESIS, 772, 46 - 54, 英語, 国際誌

    [査読有り]

    研究論文(学術雑誌)

  • Takahito Moriwaki, Seiji Kato, Yuichi Kato, Ayaka Hosoki, Qiu-Mei Zhang-Akiyama

    Excessive generation of reactive oxygen species within cells results in oxidative stress. Furthermore, accumulation of reactive oxygen species has been shown to reduce cell longevity. Many dietary supplements are believed to have anti-aging effects. The herb mixture KPG-7 contains several components with antioxidant activity. We aim to clarify the mechanisms responsible for the antioxidant activity of KPG-7 and to establish whether KPG-7 has an anti-aging effect. We examined whether dietary supplementation with KPG-7 could provide protection against oxidative stress, extend lifespan, and delay aging in Caenorhabditis elegans (C. elegans). We found that KPG-7 extended lifespan and delayed aging in adult C. elegans. The expression of oxidation resistance 1 protein was induced by juglone and this effect was significantly suppressed in KPG-7-treated. In addition, the amount of oxidized protein was significantly lower in KPG-7-treated worms than untreated worms. Furthermore, locomotive activity was increased in C elegans at 3 days of age following the treatment with KPG7. On the other hand, the level of cellular ATP was lower at 3 days of age in worms treated with KPG-7 than in untreated worms. KPG-7 increases lifespan and delays aging in C. elegans, well corresponding to its activity to protect against oxidative stress.

    JOURNAL CLINICAL BIOCHEMISTRY & NUTRITION, 2013年09月, JOURNAL OF CLINICAL BIOCHEMISTRY AND NUTRITION, 53 (2), 81 - 88, 英語, 国内誌

    [査読有り]

    研究論文(学術雑誌)

  • Tomoki Oyama, Yuichi Kato, Katsuya Satoh, Yutaka Oono, Mami Matsuda, Tomohisa Hasunuma, Akihiko Kondo

    Elsevier BV, 2021年12月, Algal Research, 60, 102544 - 102544

    研究論文(学術雑誌)

  • Akihiko Kanamoto, Yuichi Kato, Erina Yoshida, Tomohisa Hasunuma, Akihiko Kondo

    The natural pigment fucoxanthin has attracted global attention because of its superior antioxidant properties. The haptophyte marine microalgae Pavlova spp. are assumed to be promising industrial fucoxanthin producers as their lack of a cell wall could facilitate the commercialization of cultured cells as a whole food. This study screened promising Pavlova strains with high fucoxanthin content to develop an outdoor cultivation method for fucoxanthin production. Initial laboratory investigations of P. pinguis NBRC 102807, P. lutheri NBRC 102808, and Pavlova sp. OPMS 30543 identified OPMS 30543 as having the highest fucoxanthin content. The culture conditions were optimized for OPMS 30543. Compared with f/2 and Walne's media, the use of Daigo's IMK medium led to the highest biomass production and highest fucoxanthin accumulation. The presence of seawater elements in Daigo's IMK medium was necessary for the growth of OPMS 30543. OPMS 30543 was then cultured outdoors using acrylic pipe photobioreactors, a plastic bag, an open tank, and a raceway pond. Acrylic pipe photobioreactors with small diameters enabled the highest biomass production. Using an acrylic pipe photobioreactor with 60-mm diameter, a fucoxanthin productivity of 4.88 mg/L/day was achieved in outdoor cultivation. Thus, this study demonstrated the usefulness of Pavlova sp. OPMS 30543 for fucoxanthin production in outdoor cultivation.

    2021年04月, Marine biotechnology (New York, N.Y.), 23 (2), 331 - 341, 英語, 国際誌

    研究論文(学術雑誌)

  • Yuichi Kato, Tomohisa Hasunuma

    Eukaryotic microalgae and prokaryotic cyanobacteria are diverse photosynthetic organisms that produce various useful compounds. Due to their rapid growth and efficient biomass production from carbon dioxide and solar energy, microalgae and cyanobacteria are expected to become cost-effective, sustainable bioresources in the future. These organisms also abundantly produce various carotenoids, but further improvement in carotenoid productivity is needed for a successful commercialization. Metabolic engineering via genetic manipulation and mutational breeding is a powerful tool for generating carotenoid-rich strains. This chapter focuses on carotenoid production in microalgae and cyanobacteria, as well as strategies and potential target genes for metabolic engineering. Recent achievements in metabolic engineering that improved carotenoid production in microalgae and cyanobacteria are also reviewed.

    2021年, Advances in experimental medicine and biology, 1261, 121 - 135, 英語, 国際誌

    研究論文(学術雑誌)

MISC

  • 光合成メタボロミクスの物質生産への応用

    加藤悠一, 秀瀬涼太, 蓮沼誠久

    2021年09月, 生物工学会誌, 99 (9), 456 - 460, 日本語

  • 微細藻類を利用したバイオ燃料とカロテノイド類の生産

    加藤 悠一, 蓮沼 誠久

    2016年11月, レーザー研究, 11, 731 - 734, 日本語

    記事・総説・解説・論説等(学術雑誌)

  • 生殖・発生・寿命における塩基除去修復の意義

    加藤 悠一, 船越 昌史, 林 悠一郎, 秋山(張) 秋梅

    2015年06月, 放射線生物研究, 50 (2), 185 - 197, 日本語

    [査読有り]

    記事・総説・解説・論説等(学術雑誌)

  • Analysis of human DIMT1L and TFB1M homologous to KsgA, a DNA glycosylase in E.coli

    Yuichiro Hayashi, Masahiro Miyaji, Yuichi Kato, Qiu-mei Zhang Akiyama

    GENETICS SOC JAPAN, 2014年12月, GENES & GENETIC SYSTEMS, 89 (6), 311 - 311, 英語

    研究発表ペーパー・要旨(国際会議)

  • The analysis of specular affinity of C. elegans MutSalpha

    Takahito Moriwaki, Satoru Ishikawa, Yuichi Kato, Qiu-Mei Akiyama

    GENETICS SOC JAPAN, 2013年12月, GENES & GENETIC SYSTEMS, 88 (6), 361 - 361, 英語

    研究発表ペーパー・要旨(国際会議)

  • 線虫C.elegansにおける8‐oxoGに対する防御機構の解析

    石川悟, 森脇隆仁, 真田悠生, 加藤悠一, 宮路将弘, 秋山(張)秋梅

    2013年, 日本分子生物学会年会プログラム・要旨集(Web), 36th, WEB ONLY 3P-0158, 日本語

  • The difference of specificity of mismatch proteins between protostome and deuterostomia

    Takahito Moriwaki, Satoru Ishikawa, Yuichi Kato, Qiu-Mei Zhang-Akiyama

    GENETICS SOC JAPAN, 2012年12月, GENES & GENETIC SYSTEMS, 87 (6), 424 - 424, 英語

    研究発表ペーパー・要旨(国際会議)

  • Exploration of the factors of loop mismatch repair in C. elegans

    Takahito Moriwaki, Satoru Ishikawa, Yuichi Kato, Kazunari Hashiguchi, Qiu-mei Akiyama-Zhang

    GENETICS SOC JAPAN, 2011年12月, GENES & GENETIC SYSTEMS, 86 (6), 427 - 427, 英語

    研究発表ペーパー・要旨(国際会議)

  • Functional analysis of C. elegans APN-1 that is involved in the repair of AP sites

    Qiumei Akiyama-Zhang, Yuichi Kato, Kazunari Hashiguchi

    GENETICS SOC JAPAN, 2010年12月, GENES & GENETIC SYSTEMS, 85 (6), 436 - 436, 英語

    研究発表ペーパー・要旨(国際会議)

  • 線虫C.elegansにおける酸化DNAの修復

    真田 悠生, 加藤 悠一, 森脇 隆仁, 橋口 一成, 秋山(張) 秋梅

    著者等は、酸化損傷ゲノムの安定性維持機構を解明する目的で、線虫Caenorhabditis elegansの塩基除去修復(BER)機構を中心とした解析を行っている。線虫におけるBER経路の初期過程で働くDNAグリコシラーゼおよびAPエンドヌクレアーゼについて解説し、ヌクレオチドループに含まれる酸化損傷ヌクレオチドの浄化に関わる酵素に関する最近の所見を紹介した。また、線虫における8-オキシグアニンの修復機構について考察した。

    放射線生物研究会, 2010年09月, 放射線生物研究, 45 (3), 286 - 302, 日本語

    [査読有り]

    記事・総説・解説・論説等(学術雑誌)

  • Base excision repair enzymes and the roles in maintenance of the genome stability in the nematode Caenorhabditis elegans

    Qin-Mei Zhang-Akiyama, Nobuya Nakamura, Hironobu Morinaga, Shota Asai, U. Sanada, Yuichi Kato, Takahito Moriwaki

    GENETICS SOC JAPAN, 2009年12月, GENES & GENETIC SYSTEMS, 84 (6), 502 - 502, 英語

    研究発表ペーパー・要旨(国際会議)

  • 秋山(張)秋梅, 加藤悠一, 真田悠生, 浅井翔太, 森永浩伸, 中村允耶, 橋口一成

    (一社)日本放射線影響学会, 2009年11月01日, 日本放射線影響学会大会講演要旨集, 52nd, 118 - 118, 日本語

  • 線虫の塩基除去修復とゲノム安定性

    秋山(張)秋梅, 中村允耶, 森永浩伸, 浅井翔太, 真田悠生, 加藤悠一, 森脇隆仁

    2009年08月28日, 日本遺伝学会大会プログラム・予稿集, 81st, 85, 日本語

  • C.elegansの酸化DNA修復酵素とストレス応答タンパク質のゲノム安定性への関与

    AKIYAMA‐ZHANG Qui‐Mei, 真田悠生, 浅井翔太, 加藤悠一, 森脇隆仁, 橋口一成, 森永浩伸, 中村允耶

    2009年, 日本分子生物学会年会講演要旨集, 32nd (Vol.1), 83, 日本語

書籍等出版物

  • Carotenoids: Biosynthetic and Biofunctional Approaches

    Yuichi Kato, Tomohisa Hasunuma

    Metabolic Engineering for Carotenoid Production Using Eukaryotic Microalgae and Prokaryotic Cyanobacteria, Springer, 2021年

講演・口頭発表等

  • 食品農業におけるLEDの利活用技術の開発

    藤川康夫, 鶴本智大, 泉田智史, 三島俊介, 岡澤敦司, 加藤悠一, 蓮沼誠久

    第71回日本生物工学会大会, 2019年09月, 日本語, 国内会議

    ポスター発表

  • 窒素源存在下で油脂を高蓄積する海洋性クラミドモナス変異株の選択的育種

    小山 智己, 加藤 悠一, 佐藤 勝也, 大野 豊, 蓮沼 誠久, 近藤 昭彦

    第71回日本生物工学会大会, 2019年09月, 日本語, 岡山大学, 国内会議

    口頭発表(一般)

  • 海洋性クラミドモナス油脂高蓄積変異株における油脂・カロテノイド増産メカニズムの解明

    加藤 悠一, 小山 智己, 佐藤 勝也, 大野 豊, 張 嘉修, 蓮沼 誠久, 近藤 昭彦

    第71回日本生物工学会大会, 2019年09月, 日本語, 岡山大学, 国内会議

    口頭発表(一般)

  • 緑色LEDを用いた微細藻類バイオマス増産技術の開発

    加藤 悠一, 藤川 康夫, 三島 俊介, 泉田 智史, 蓮沼 誠久, 近藤 昭彦

    日本農芸化学会2019年度大会, 2019年03月, 日本語, 東京農業大学 世田谷キャンパス, 国内会議

    ポスター発表

  • 油脂高蓄積クラミドモナス株の選抜育種によるバイオ燃料生産「明暗周期問題」の克服

    加藤 悠一, 藤原 悠右, 小山 智己, 張 嘉修, 蓮沼 誠久, 近藤 昭彦

    第69回日本生物工学会大会, 2017年09月, 日本語, 日本生物工学会, 東京都新宿区, 国内会議

    口頭発表(一般)

  • 代謝工学による黄色天然色素ルテイン高蓄積クラミドモナス株の創出

    阪口 健太, 加藤 悠一, 蓮沼 誠久, 近藤 昭彦

    第69回日本生物工学会大会, 2017年09月, 日本語, 日本生物工学会, 東京都新宿区, 国内会議

    ポスター発表

  • バイオ燃料生産に向けた耐塩性緑藻の進化工学的育種と 塩ストレス耐性による油脂生産低下メカニズムの解明

    加藤 悠一, 賀 詩欣, 張 嘉修, 蓮沼 誠久, 近藤 昭彦

    日本農芸化学会2017年度大会, 2017年03月, 日本語, 京都女子大学, 国内会議

    口頭発表(一般)

  • Evolutionary Breeding of the Microalga Chamydomonas sp. Strains Resistant to High Salinity and Evaluation of Their Lipid

    加藤 悠一

    i-BioP, 2016年12月, 英語, Haeundae Grand Hotel, Pusan Korea, 国際会議

    ポスター発表

所属学協会

  • 日本農芸化学会

  • 日本生物工学会

共同研究・競争的資金等の研究課題

  • 微細藻類における油脂「低」蓄積変異株の育種とそのメタボローム解析

    加藤 悠一

    日本学術振興会, 科学研究費助成事業 若手研究, 若手研究, 神戸大学, 2020年04月01日 - 2023年03月31日

    微細藻類は光合成により二酸化炭素を固定して油脂を多量に合成する。光合成的に生成する炭素源を油脂として蓄積するのではなく別の物質の合成に利用できれば、その生産性は飛躍的に向上すると思われる。それには油脂の合成不全を起こした油脂低蓄積変異株を宿主として利用する方法が考えられるが、そのような変異株はバイオ燃料生産者としての有用性が低いため、これまでに詳細な解析がなされていない。本研究では、油脂低蓄積変異株の利用可能性を検証し、この生産戦略の学術的基盤を構築するため、微細藻類クラミドモナスの油脂低蓄積変異株を育種し、油脂含有率低下の影響を代謝レベル・遺伝子レベルで解明する。 本年度は、油脂低蓄積変異株の作出に向けて、親株の選定と形質転換手法の確立に取り組んだ。本研究では、抗生物質耐性カセットをゲノム中のランダムな部位に挿入することで遺伝子破壊株のライブラリを用意する。エキソンに対しての耐性カセット挿入が望ましいため、遺伝子数やエキソン領域の割合を考慮して10^5種類以上の形質転換体を含むライブラリを作成することを目標としている。まずは一般的なクラミドモナス野生株を用いて耐性カセットの導入を実施したが、この目標に対しては形質転換効率が低いことがわかった。そこで、細胞壁欠損株を含む数種類のクラミドモナス候補株を新たに用意し、油脂含有率と形質転換効率の観点から親株の選定を実施した。また選定した親株においてエレクトロポレーション条件などの見直しを行い、目標とするサイズのライブラリを得るのに十分な形質転換効率を達成した。

産業財産権

  • カロテノイド高蓄積株の選抜方法、カロテノイド高蓄積変異株及びそれを用いたカロテノイドの製造方法

    蓮沼 誠久, 加藤 悠一, 近藤 昭彦, 太郎田 博之, 江原 岳, 國分 夢, 皆川 純, 佐藤 諒一

    特願2020-187861, 2020年11月11日, 国立大学法人神戸大学, DIC株式会社, 大学共同利用機関法人自然科学研究機構, 特開2021-073996, 2021年05月20日

    特許権

  • 窒素源存在条件下オイル高蓄積藻類株の育種方法、窒素源存在条件下オイル高蓄積藻類株及びそれを用いた油脂製造方法

    蓮沼 誠久, 加藤 悠一, 小山 智己, 近藤 昭彦, 佐藤 勝也, 大野 豊

    特願2019-145222, 2019年08月07日, 国立大学法人神戸大学, 国立研究開発法人量子科学技術研究開発機構, 特開2021-023234, 2021年02月22日

    特許権

  • オイル高蓄積有用藻類株の育種方法、藻類のオイル高蓄積変異株及びそれを用いた油脂の製造方法

    蓮沼 誠久, 加藤 悠一, 近藤 昭彦, 佐藤 勝也, 大野 豊

    特願2019-104643, 2019年06月04日, 国立大学法人神戸大学, 国立研究開発法人量子科学技術研究開発機構, 特開2020-195344, 2020年12月10日

    特許権

  • 藻類を培養する方法及びフォトバイオリアクター

    蓮沼 誠久, 加藤 悠一, 藤川 康夫, 鶴本 智大

    特願2020-015613, 2020年01月31日, 国立大学法人神戸大学, 日亜化学工業株式会社, 特開2020-137514, 2020年09月03日

    特許権