@article{pmid37317151,
title = {Plastoquinone Lipids: Their Synthesis via a Bifunctional Gene and Physiological Function in a Euryhaline Cyanobacterium, Plastoquinone Lipids: Their Synthesis via a Bifunctional Gene and Physiological Function in a Euryhaline Cyanobacterium, \textit{Synechococcus} sp. PCC 7002},
author = {Mimari Kondo and Motohide Aoki and Kazuho Hirai and Ryo Ito and Mikio Tsuzuki and Norihiro Sato},
doi = {10.3390/microorganisms11051177},
issn = {2076-2607},
year = {2023},
date = {2023-04-01},
urldate = {2023-04-01},
journal = {Microorganisms},
volume = {11},
number = {5},
abstract = {Eukaryotic photosynthetic organisms synthesize triacylglycerols, which are crucial physiologically as major carbon and energy storage compounds and commercially as food oils and raw materials for carbon-neutral biofuel production. TLC analysis has revealed triacylglycerols are present in several cyanobacteria. However, mass spectrometric analysis has shown that freshwater cyanobacterium, sp. PCC 6803, contains plastoquinone-B and acyl plastoquinol with triacylglycerol-like TLC mobility, concomitantly with the absence of triacylglycerol. contains , which is responsible for the bifunctional synthesis of plastoquinone-B and acyl plastoquinol and also for NaCl-stress acclimatizing cell growth. However, information is limited on the taxonomical distribution of these plastoquinone lipids, and their synthesis genes and physiological roles in cyanobacteria. In this study, a euryhaline cyanobacterium, sp. PCC 7002, shows the same plastoquinone lipids as those in , although the levels are much lower than in , triacylglycerol being absent. Furthermore, through an analysis of a disruptant to the homolog of in , it is found that the homolog in , similar to in , contributes bifunctionally to the synthesis of plastoquinone-B and acyl plastoquinol; however, the extent of the contribution of the homolog gene to NaCl acclimatization is smaller than that of in . These observations suggest strain- or ecoregion-dependent development of the physiological roles of plastoquinone lipids in cyanobacteria and show the necessity to re-evaluate previously identified cyanobacterial triacylglycerol through TLC analysis with mass spectrometric techniques.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Eukaryotic photosynthetic organisms synthesize triacylglycerols, which are crucial physiologically as major carbon and energy storage compounds and commercially as food oils and raw materials for carbon-neutral biofuel production. TLC analysis has revealed triacylglycerols are present in several cyanobacteria. However, mass spectrometric analysis has shown that freshwater cyanobacterium, sp. PCC 6803, contains plastoquinone-B and acyl plastoquinol with triacylglycerol-like TLC mobility, concomitantly with the absence of triacylglycerol. contains , which is responsible for the bifunctional synthesis of plastoquinone-B and acyl plastoquinol and also for NaCl-stress acclimatizing cell growth. However, information is limited on the taxonomical distribution of these plastoquinone lipids, and their synthesis genes and physiological roles in cyanobacteria. In this study, a euryhaline cyanobacterium, sp. PCC 7002, shows the same plastoquinone lipids as those in , although the levels are much lower than in , triacylglycerol being absent. Furthermore, through an analysis of a disruptant to the homolog of in , it is found that the homolog in , similar to in , contributes bifunctionally to the synthesis of plastoquinone-B and acyl plastoquinol; however, the extent of the contribution of the homolog gene to NaCl acclimatization is smaller than that of in . These observations suggest strain- or ecoregion-dependent development of the physiological roles of plastoquinone lipids in cyanobacteria and show the necessity to re-evaluate previously identified cyanobacterial triacylglycerol through TLC analysis with mass spectrometric techniques.
@article{pmid37180399,
title = {\textit{slr2103}, a homolog of type-2 diacylglycerol acyltransferase genes, for plastoquinone-related neutral lipid synthesis and NaCl-stress acclimatization in a cyanobacterium, \textit{Synechocystis} sp. PCC 6803},
author = {Mimari Kondo and Motohide Aoki and Kazuho Hirai and Taku Sagami and Ryo Ito and Mikio Tsuzuki and Norihiro Sato},
doi = {10.3389/fpls.2023.1181180},
issn = {1664-462X},
year = {2023},
date = {2023-01-01},
urldate = {2023-01-01},
journal = {Front Plant Sci},
volume = {14},
pages = {1181180},
abstract = {A cyanobacterium, sp. PCC 6803, contains a lipid with triacylglycerol-like TLC mobility but its identity and physiological roles remain unknown. Here, on ESI-positive LC-MS analysis, it is shown that the triacylglycerol-like lipid (lipid X) is related to plastoquinone and can be grouped into two subclasses, X and X, the latter of which is esterified by 16:0 and 18:0. This study further shows that a homolog of type-2 diacylglycerol acyltransferase genes, , is essential for lipid X synthesis: lipid X disappears in a -disruptant whereas it appears in an -overexpressing transformant (OE) of PCC 7942 that intrinsically lacks lipid X. The disruption causes cells to accumulate plastoquinone-C at an abnormally high level whereas overexpression in causes the cells to almost completely lose it. It is thus deduced that encodes a novel acyltransferase that esterifies 16:0 or 18:0 with plastoquinone-C for the synthesis of lipid X. Characterization of the -disruptant in shows that contributes to sedimented-cell growth in a static culture, and to bloom-like structure formation and its expansion by promoting cell aggregation and floatation upon imposition of saline stress (0.3-0.6 M NaCl). These observations provide a basis for elucidation of the molecular mechanism of a novel cyanobacterial strategy to acclimatize to saline stress, and one for development of a system of seawater-utilization and economical harvesting of cyanobacterial cells with high-value added compounds, or blooming control of toxic cyanobacteria.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
A cyanobacterium, sp. PCC 6803, contains a lipid with triacylglycerol-like TLC mobility but its identity and physiological roles remain unknown. Here, on ESI-positive LC-MS analysis, it is shown that the triacylglycerol-like lipid (lipid X) is related to plastoquinone and can be grouped into two subclasses, X and X, the latter of which is esterified by 16:0 and 18:0. This study further shows that a homolog of type-2 diacylglycerol acyltransferase genes, , is essential for lipid X synthesis: lipid X disappears in a -disruptant whereas it appears in an -overexpressing transformant (OE) of PCC 7942 that intrinsically lacks lipid X. The disruption causes cells to accumulate plastoquinone-C at an abnormally high level whereas overexpression in causes the cells to almost completely lose it. It is thus deduced that encodes a novel acyltransferase that esterifies 16:0 or 18:0 with plastoquinone-C for the synthesis of lipid X. Characterization of the -disruptant in shows that contributes to sedimented-cell growth in a static culture, and to bloom-like structure formation and its expansion by promoting cell aggregation and floatation upon imposition of saline stress (0.3-0.6 M NaCl). These observations provide a basis for elucidation of the molecular mechanism of a novel cyanobacterial strategy to acclimatize to saline stress, and one for development of a system of seawater-utilization and economical harvesting of cyanobacterial cells with high-value added compounds, or blooming control of toxic cyanobacteria.
@article{Oishi2022,
title = {Diacylglyceryl-\textit{N,N,N}-trimethylhomoserine-dependent lipid remodeling in a green alga, \textit{Chlorella kessleri</I>},
author = {Yutaro Oishi and Rie Otaki and Yukari Iijima and Eri Kumagai and Motohide Aoki and Mikio Tsuzuki and Shoko Fujiwara and Norihiro Sato},
url = {https://doi.org/10.1038/s42003-021-02927-z},
doi = {10.1038/s42003-021-02927-z},
issn = {2399-3642},
year = {2022},
date = {2022-01-01},
urldate = {2022-01-01},
journal = {Communications Biology},
volume = {5},
number = {1},
pages = {19},
abstract = {Membrane lipid remodeling contributes to the environmental acclimation of plants. In the green lineage, a betaine lipid, diacylglyceryl-N,N,N-trimethylhomoserine (DGTS), is included exclusively among green algae and nonflowering plants. Here, we show that the green alga Chlorella kessleri synthesizes DGTS under phosphorus-deficient conditions through the eukaryotic pathway via the ER. Simultaneously, phosphatidylcholine and phosphatidylethanolamine, which are similar to DGTS in their zwitterionic properties, are almost completely degraded to release 18.1% cellular phosphorus, and to provide diacylglycerol moieties for a part of DGTS synthesis. This lipid remodeling system that substitutes DGTS for extrachloroplast phospholipids to lower the P-quota operates through the expression induction of the BTA1 gene. Investigation of this lipid remodeling system is necessary in a wide range of lower green plants for a comprehensive understanding of their phosphorus deficiency acclimation strategies.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Membrane lipid remodeling contributes to the environmental acclimation of plants. In the green lineage, a betaine lipid, diacylglyceryl-N,N,N-trimethylhomoserine (DGTS), is included exclusively among green algae and nonflowering plants. Here, we show that the green alga Chlorella kessleri synthesizes DGTS under phosphorus-deficient conditions through the eukaryotic pathway via the ER. Simultaneously, phosphatidylcholine and phosphatidylethanolamine, which are similar to DGTS in their zwitterionic properties, are almost completely degraded to release 18.1% cellular phosphorus, and to provide diacylglycerol moieties for a part of DGTS synthesis. This lipid remodeling system that substitutes DGTS for extrachloroplast phospholipids to lower the P-quota operates through the expression induction of the BTA1 gene. Investigation of this lipid remodeling system is necessary in a wide range of lower green plants for a comprehensive understanding of their phosphorus deficiency acclimation strategies.
@article{MIYAUCHI2021102394,
title = {Development of an algal cell-attached solid surface culture system for simultaneous wastewater treatment and biomass production},
author = {Hiroki Miyauchi and Kohei Harada and Yoshino Suzuki and Katsuhiko Okada and Motohide Aoki and Tomonari Umemura and Shoko Fujiwara and Mikio Tsuzuki},
url = {https://www.sciencedirect.com/science/article/pii/S2211926421002137},
doi = {https://doi.org/10.1016/j.algal.2021.102394},
issn = {2211-9264},
year = {2021},
date = {2021-07-06},
journal = {Algal Research},
volume = {58},
pages = {102394},
abstract = {Wastewater treatment using microalgae is receiving growing attention. Here, we have developed a portable tubular system containing an algal cell-coated solid surface for phosphorous recovery. P-depleted Chlorella cells attached to a solid surface removed phosphate from the medium about 70 times faster than P-replete cells. When the cell density was 20 g dry cell weight m−2 or less, P-depleted cells on the solid surface absorbed phosphate from the medium at almost the same rate as in liquid, the maximum capacity per solid surface area being about 6 mg P m−2 min−1. P in inorganic wastewater from chemical factories (ethanol factories; about 4 mg L−1) and in pond water (0.06 mg L−1) was mostly removed within 3 h with a simple device composed of a single solid-surfaced sheet (0.002 m−2) and a portable compact tubular device including 12 such sheets (totally 0.5 m−2), respectively. Simultaneously, cellular growth was confirmed with both wastewater and pond water. These findings suggested that the attached cell culture system, in which medium exchange to prepare P-depleted cells is much easier than in liquid cultures, is promising for dual use for biomass production and wastewater treatment.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Wastewater treatment using microalgae is receiving growing attention. Here, we have developed a portable tubular system containing an algal cell-coated solid surface for phosphorous recovery. P-depleted Chlorella cells attached to a solid surface removed phosphate from the medium about 70 times faster than P-replete cells. When the cell density was 20 g dry cell weight m−2 or less, P-depleted cells on the solid surface absorbed phosphate from the medium at almost the same rate as in liquid, the maximum capacity per solid surface area being about 6 mg P m−2 min−1. P in inorganic wastewater from chemical factories (ethanol factories; about 4 mg L−1) and in pond water (0.06 mg L−1) was mostly removed within 3 h with a simple device composed of a single solid-surfaced sheet (0.002 m−2) and a portable compact tubular device including 12 such sheets (totally 0.5 m−2), respectively. Simultaneously, cellular growth was confirmed with both wastewater and pond water. These findings suggested that the attached cell culture system, in which medium exchange to prepare P-depleted cells is much easier than in liquid cultures, is promising for dual use for biomass production and wastewater treatment.
@article{今崎龍之介2020,
title = {超薄層クロマトグラフィー用の水平式ミニチュアTLC展開槽の試作と評価},
author = {今崎,龍之介 and 近藤,啓太 and 谷,夏海 and 青木,元秀 and 熊田,英峰 and 内田,達也 and 長縄,豪 and 嶋田,泰佑 and 田口,嘉彦 and 佐藤,浩明 and 安井,隆雄 and 梅村,知也},
doi = {10.2116/bunsekikagaku.69.553},
year = {2020},
date = {2020-01-01},
journal = {分析化学},
volume = {69},
number = {10.11},
pages = {553-558},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
@article{Tani2019,
title = {Short-lived long noncoding RNAs as surrogate indicators for chemical stress in HepG2 cells and their degradation by nuclear RNases},
author = {Hidenori Tani and Ayaka Numajiri and Motohide Aoki and Tomonari Umemura and Tetsuya Nakazato},
url = {www.nature.com/scientificreports},
doi = {https://doi.org/10.1038/s41598-019-56869-y},
issn = {2045-2322},
year = {2019},
date = {2019-12-30},
journal = {Scientific Reports},
volume = {9},
pages = {20299},
abstract = {Long noncoding RNAs (lncRNAs) are non-protein-coding transcripts >200 nucleotides in length that have been shown to play important roles in various biological processes. The mechanisms underlying the induction of lncRNA expression by chemical exposure remain to be determined. We identified a novel class of short-lived lncRNAs with half-lives (t1/2) ≤4 hours in human HeLa Tet-off cells, which have been suggested to express many lncRNAs with regulatory functions. As they may affect various human biological processes, short-lived lncRNAs may be useful indicators of the degree of stress on chemical exposure. In the present study, we identified four short-lived lncRNAs, designated as OIP5-AS1, FLJ46906, LINC01137, and GABPB1-AS1, which showed significantly upregulated expression following exposure to hydrogen peroxide (oxidative stress), mercury II chloride (heavy metal stress), and etoposide (DNA damage stress) in human HepG2 cells. These lncRNAs may be useful indicators of chemical stress responses. The levels of these lncRNAs in the cells were increased because of chemical stress-induced prolongation of their decay. These lncRNAs were degraded by nuclear RNases, which are components of the exosome and XRN2, and chemical exposure inhibited the RNase activities within the cells.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Long noncoding RNAs (lncRNAs) are non-protein-coding transcripts >200 nucleotides in length that have been shown to play important roles in various biological processes. The mechanisms underlying the induction of lncRNA expression by chemical exposure remain to be determined. We identified a novel class of short-lived lncRNAs with half-lives (t1/2) ≤4 hours in human HeLa Tet-off cells, which have been suggested to express many lncRNAs with regulatory functions. As they may affect various human biological processes, short-lived lncRNAs may be useful indicators of the degree of stress on chemical exposure. In the present study, we identified four short-lived lncRNAs, designated as OIP5-AS1, FLJ46906, LINC01137, and GABPB1-AS1, which showed significantly upregulated expression following exposure to hydrogen peroxide (oxidative stress), mercury II chloride (heavy metal stress), and etoposide (DNA damage stress) in human HepG2 cells. These lncRNAs may be useful indicators of chemical stress responses. The levels of these lncRNAs in the cells were increased because of chemical stress-induced prolongation of their decay. These lncRNAs were degraded by nuclear RNases, which are components of the exosome and XRN2, and chemical exposure inhibited the RNase activities within the cells.
@article{Nagashimae201900308,
title = {MITOL deletion in the brain impairs mitochondrial structure and ER tethering leading to oxidative stress},
author = {Nagashima, Shun and Takeda, Keisuke and Ohno, Nobuhiko and Ishido, Satoshi and Aoki, Motohide and Saitoh, Yurika and Takada, Takumi and Tokuyama, Takeshi and Sugiura, Ayumu and Fukuda, Toshifumi and Matsushita, Nobuko and Inatome, Ryoko and Yanagi, Shigeru},
url = {https://www.life-science-alliance.org/content/2/4/e201900308},
doi = {10.26508/lsa.201900308},
year = {2019},
date = {2019-08-15},
journal = {Life Science Alliance},
volume = {2},
number = {4},
publisher = {Life Science Alliance},
abstract = {Mitochondrial abnormalities are associated with developmental disorders, although a causal relationship remains largely unknown. Here, we report that increased oxidative stress in neurons by deletion of mitochondrial ubiquitin ligase MITOL causes a potential neuroinflammation including aberrant astrogliosis and microglial activation, indicating that mitochondrial abnormalities might confer a risk for inflammatory diseases in brain such as psychiatric disorders. A role of MITOL in both mitochondrial dynamics and ER-mitochondria tethering prompted us to characterize three-dimensional structures of mitochondria in vivo. In MITOL-deficient neurons, we observed a significant reduction in the ER-mitochondria contact sites, which might lead to perturbation of phospholipids transfer, consequently reduce cardiolipin biogenesis. We also found that branched large mitochondria disappeared by deletion of MITOL. These morphological abnormalities of mitochondria resulted in enhanced oxidative stress in brain, which led to astrogliosis and microglial activation partly causing abnormal behavior. In conclusion, the reduced ER-mitochondria tethering and excessive mitochondrial fission may trigger neuroinflammation through oxidative stress.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Mitochondrial abnormalities are associated with developmental disorders, although a causal relationship remains largely unknown. Here, we report that increased oxidative stress in neurons by deletion of mitochondrial ubiquitin ligase MITOL causes a potential neuroinflammation including aberrant astrogliosis and microglial activation, indicating that mitochondrial abnormalities might confer a risk for inflammatory diseases in brain such as psychiatric disorders. A role of MITOL in both mitochondrial dynamics and ER-mitochondria tethering prompted us to characterize three-dimensional structures of mitochondria in vivo. In MITOL-deficient neurons, we observed a significant reduction in the ER-mitochondria contact sites, which might lead to perturbation of phospholipids transfer, consequently reduce cardiolipin biogenesis. We also found that branched large mitochondria disappeared by deletion of MITOL. These morphological abnormalities of mitochondria resulted in enhanced oxidative stress in brain, which led to astrogliosis and microglial activation partly causing abnormal behavior. In conclusion, the reduced ER-mitochondria tethering and excessive mitochondrial fission may trigger neuroinflammation through oxidative stress.
@article{竹内理子2019,
title = {化合物レベル炭素安定同位体比分析のための高等植物中のステロール及び脂肪酸の分離精製法の確立},
author = { 竹内, 理子 and 力石, 嘉人 and 小川, 奈々子 and 風呂田, 郷史 and 大河内, 直彦 and 青木, 元秀 and 内田, 達也 and 梅村, 知也 and 熊田, 英峰},
doi = {10.2116/bunsekikagaku.68.297},
year = {2019},
date = {2019-04-01},
journal = {分析化学},
volume = {68},
number = {5},
pages = {297-306},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
@article{MUROTA2019101410,
title = {Hyper-resistance to arsenate in the cyanobacterium Synechocystis sp. PCC 6803 is influenced by the differential kinetics of its pst-ABC transporters and external phosphate concentration exposure},
author = {Chisato Murota and Shoko Fujiwara and Maki Tsujishita and Kanae Urabe and Shuta Takayanagi and Motohide Aoki and Tomonari Umemura and Julian J. Eaton-Rye and Frances D. Pitt and Mikio Tsuzuki},
url = {http://www.sciencedirect.com/science/article/pii/S2211926418307380},
doi = {https://doi.org/10.1016/j.algal.2019.101410},
issn = {2211-9264},
year = {2019},
date = {2019-01-01},
journal = {Algal Research},
volume = {38},
pages = {101410},
abstract = {Phosphate transporters, which take up not only phosphate but also arsenate, have attracted attention for phosphorus (P) resource recovery from eutrophic environments and arsenic (As) removal from polluted areas by bioremediation. The cyanobacterium Synechocystis sp. PCC 6803 can grow in a higher ratio of arsenate (150 mM) to phosphate (0.2 mM) in comparison with plants and microalgae. Analysis of the As resistance of the Pst1 and Pst2 phosphate transporter deletion mutants (Δpst1 and Δpst2) showed that the Δpst1 strain is more sensitive to arsenate under P-replete conditions but more resistant under P-deplete conditions compared with Δpst2 cells and wild type. This pattern in sensitivity is attributed to the levels of initial As accumulation and pst gene expression. Moreover, the ratio of phosphate uptake to arsenate uptake rates at 10 μM was 7–10:1 in the wild type and the Δpst2 mutant, while that in Δpst1 and Δ pstS1 (phosphate-binding protein from the pst1 gene cluster), were about 1.5:1, suggesting a high selectivity of Pst1 for phosphate.},
keywords = {},
pubstate = {published},
tppubtype = {article}
}
Phosphate transporters, which take up not only phosphate but also arsenate, have attracted attention for phosphorus (P) resource recovery from eutrophic environments and arsenic (As) removal from polluted areas by bioremediation. The cyanobacterium Synechocystis sp. PCC 6803 can grow in a higher ratio of arsenate (150 mM) to phosphate (0.2 mM) in comparison with plants and microalgae. Analysis of the As resistance of the Pst1 and Pst2 phosphate transporter deletion mutants (Δpst1 and Δpst2) showed that the Δpst1 strain is more sensitive to arsenate under P-replete conditions but more resistant under P-deplete conditions compared with Δpst2 cells and wild type. This pattern in sensitivity is attributed to the levels of initial As accumulation and pst gene expression. Moreover, the ratio of phosphate uptake to arsenate uptake rates at 10 μM was 7–10:1 in the wild type and the Δpst2 mutant, while that in Δpst1 and Δ pstS1 (phosphate-binding protein from the pst1 gene cluster), were about 1.5:1, suggesting a high selectivity of Pst1 for phosphate.
東京薬科大学生命科学部 助教 同大学院 生命科学研究科 助教 TUPLS Assistant Professor in Life Sciences Co-director of Biochemistry and Molecular biology Research Team, Laboratory of Environmental and Bioanalytical Chemistry
資格 (License)
甲種危険物取扱者 (Class A Hazardous Materials Engineer) 認定電気工事従事者 (Journeyman Electrician Certified by METI Japan) 第二種電気工事士 (Second Class Electrician License) 一級小型船舶操縦士 (First-Class Small Boat Pilot) – 陸から離れた海洋・湖沼などでの水性生物サンプリングができます（外洋まで出れる資格ですが基本”丘”船長です） 第１級海上無線通信士 (Maritime First–Class Radio Operator) – 国際航海に対応 など
学歴 (Education)
Ph.D., Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan (2004) M.Sc., Life Sciences, Tokyo University of Pharmacy and Life Sciences, Tokyo, Japan (2001) B.Sc., Molecular Biology and Biochemistry, Saitama University, Saitama, Japan (1999)
職歴 (Previous Appointments)
Research Associate, 2005-2007, Tokyo University of Pharmacy and Life Sciences Postdoctoral Researcher, 2004-2005, Biomarker Science Co.,Ltd.
