2024/02/15 更新

写真a

キザワ アユミ
鬼沢 あゆみ
KIZAWA Ayumi
所属
理工学部 助教C
連絡先
メールによる問い合わせは《こちら》から
外部リンク

学位

  • 博士(理学) ( 埼玉大学 )

  • 修士(生命科学) ( 東北大学 )

学歴

  • 2016年3月
     

    埼玉大学   理工学研究科   理工学専攻   博士後期   修了

  • 2011年3月
     

    東北大学   生命科学研究科   生態システム生命科学専攻   博士前期   修了

  • 2009年3月
     

    埼玉大学   理学部   分子生物学科   卒業

  • 2003年3月
     

    福島県立安積黎明高等学校   卒業

経歴

  • 2019年4月 -  

    中央大学理工学部助教

  • 2018年4月 -  

    千葉大学理学部地球科学科技術補佐員

  • 2018年4月 -  

    首都大学東京理工学研究科生命科学専攻特任研究員

  • 2017年5月 - 2018年3月

    首都大学東京理工学研究科生命科学専攻客員研究員

  • 2016年4月 - 2018年3月

    明治大学農学部農芸化学科法人ポスト・ドクター

  • 2011年11月 - 2012年3月

    埼玉大学大学院理工学研究科産学官研究員

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所属学協会

  • 日本植物生理学会

  • 日本光合成学会

  • 日本微生物生態学会

研究キーワード

  • シアノバクテリア

研究分野

  • ライフサイエンス / 植物分子、生理科学

論文

  • The role of transcriptional repressor activity of LexA in salt-stress responses of the cyanobacterium Synechocystis sp. PCC 6803

    Kosuke Takashima, Syota Nagao, Ayumi Kizawa, Takehiro Suzuki, Naoshi Dohmae, Yukako Hihara

    Scientific Reports   10 ( 1 )   2020年12月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media LLC  

    <title>Abstract</title>
    Different from typical LexA repressors in heterotrophic bacteria exerting SOS response by auto-cleavage, cyanobacterial LexAs, especially that of <italic>Synechocystis</italic> sp. PCC 6803 (S.6803), have been suggested be involved in regulation of a number of genes related to various cellular processes, rather than the typical SOS regulon. When and how cyanobacterial LexAs are triggered to regulate its target genes have remained unknown. In this study, we found the profound repressing effect of LexA on salt-stress inducible genes in S<italic>.</italic>6803. The repressing activity of LexA was likely to persist during salt stress and the salt response of these genes was mainly achieved by other regulators than LexA, suggesting that the physiological role of LexA is fine-tuning of gene expression in response to environmental changes. Although the amount and oligomeric state of LexA were unchanged upon salt stress, two-dimensional electrophoresis and liquid chromatography-tandem mass spectrometry analyses detected a change in posttranslational modification in a small fraction of LexA molecules, possibly dephosphorylation of Ser173, after 30 min upon the upshift in salt concentration. Activity of LexA in S.6803 may be under gradual control by posttranslational modification to fine-tune gene expression, which is contrasted with the digital switching-off regulation by auto-cleavage in heterotrophic bacteria.

    DOI: 10.1038/s41598-020-74534-7

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    その他リンク: http://www.nature.com/articles/s41598-020-74534-7

  • Overexpression of the response regulator rpaA causes an impaired cell division in the Cyanobacterium Synechocystis sp. PCC 6803

    Ayumi Kizawa, Takashi Osanai

    The Journal of General and Applied Microbiology   66 ( 2 )   121 - 128   2020年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Microbiology Research Foundation  

    In photosynthetic microorganisms, cell cycle progression depends on day and night cycles; however, how cell division is regulated in response to these environmental changes is poorly understood. RpaA has been implicated in the signal output from both circadian clocks and light/dark conditions in the unicellular spherical-celled cyanobacterium Synechocystis sp. PCC 6803. In the present study, we investigated the involvement of a two-component response regulator RpaA in cell division regulation. Firstly, we examined the effects of rpaA overexpression on cell morphology and the expression levels of cell division genes. We observed an increase in the volume of non-dividing cells and a high proportion of dividing cells in rpaA-overexpressing strains by light microscopy. The expression levels of selected cell division-related genes were higher in the rpaA-overexpressing strain than in the wild type, including minD of the Min system; cdv3 and zipN, which encode two divisome components; and murB, murC, and pbp2, which are involved in peptidoglycan (PG) synthesis. Moreover, in the rpaA-overexpressing strain, the outer membrane and cell wall PG layer were not smooth, and the outer membrane was not clearly visible by transmission electron microscopy. These results demonstrated that rpaA overexpression causes an impaired cell division, which is accompanied by transcriptional activation of cell division genes and morphological changes in the PG layer and outer membrane.

    DOI: 10.2323/jgam.2020.01.004

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  • The LexA transcription factor regulates fatty acid biosynthetic genes in the cyanobacterium Synechocystis sp PCC 6803 査読

    Ayumi Kizawa, Akihito Kawahara, Kosuke Takashima, Yasushi Takimura, Yoshitaka Nishiyama, Yukako Hihara

    PLANT JOURNAL   92 ( 2 )   189 - 198   2017年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:WILEY  

    Specific transcription factors have been identified in various heterotrophic bacterial species that regulate the sets of genes required for fatty acid metabolism. Here, we report that expression of the fab genes, encoding fatty acid biosynthetic enzymes, is regulated by the global regulator LexA in the photoautotrophic cyanobacterium Synechocystis sp. PCC 6803. Sll1626, an ortholog of the well-known LexA repressor involved in the SOS response in heterotrophic bacteria, was isolated from crude extracts of Synechocystis by DNA affinity chromatography, reflecting its binding to the upstream region of the acpP-fabF and fabI genes. An electrophoresis mobility shift assay revealed that the recombinant LexA protein can bind to the upstream region of each fab gene tested (fabD, fabH, fabF, fabG, fabZ and fabI). Quantitative RT-PCR analysis of the wild type and a lexA-disrupted mutant strain suggested that LexA acts as a repressor of the fab genes involved in initiation of fatty acid biosynthesis (fabD, fabH and fabF) and the first reductive step in the subsequent elongation cycle (fabG) under normal growth conditions. Under nitrogen-depleted conditions, downregulation of fab gene expression is partly achieved through an increase in LexA-repressing activity. In contrast, under phosphate-depleted conditions, fab gene expression is upregulated, probably due to the loss of repression by LexA. We further demonstrate that elimination of LexA largely increases the production of fatty acids in strains modified to secrete free fatty acids.

    DOI: 10.1111/tpj.13644

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  • RNA-seq Profiling Reveals Novel Target Genes of LexA in the Cyanobacterium Synechocystis sp PCC 6803 査読

    Ayumi Kizawa, Akihito Kawahara, Yasushi Takimura, Yoshitaka Nishiyama, Yukako Hihara

    FRONTIERS IN MICROBIOLOGY   7   193   2016年2月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:FRONTIERS MEDIA SA  

    LexA is a well-established transcriptional repressor of SOS genes induced by DNA damage in Escherichia coil and other bacterial species. However, LexA in the cyanobacterium Synechocystis sp. PCC 6803 has been suggested not to be involved in SOS response. In this study, we performed RNA-seq analysis of the wild-type strain and the lexA-disrupted mutant to obtain the comprehensive view of LexA-regulated genes in Synechocystis. Disruption of lexA positively or negatively affected expression of genes related to various cellular functions such as phototactic motility, accumulation of the major compatible solute glucosylglycerol and subunits of bidirectional hydrogenase, photosystem I, and phycobilisome complexes. We also observed increase in the expression level of genes related to iron and manganese uptake in the mutant at the later stage of cultivation. However, none of the genes related to DNA metabolism were affected by disruption of lexA. DNA gel mobility shift assay using the recombinant LexA protein suggested that LexA binds to the upstream region of pilA7, pilA9, ggpS. and slr1670 to directly regulate their expression, but changes in the expression level of photosystem I genes by disruption of lexA is likely a secondary effect.

    DOI: 10.3389/fmicb.2016.00193

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  • Phylogeography of Arabis serrata (Brassicaceae) in the Japanese Archipelago based on chloroplast DNA variations 査読

    Ayumi Kizawa, Masayuki Maki

    PLANT SPECIES BIOLOGY   31 ( 1 )   65 - 72   2016年1月

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    記述言語:英語   出版者・発行元:WILEY-BLACKWELL  

    Arabis serrata (Brassicaceae), a perennial plant widely distributed along the Japanese Archipelago, occurs in various habitats: for example, limestone zones, serpentine barrens, volcanic soils, and roadsides. It likely survived by adapting to its surrounding environment, resulting in great morphological and ecological variation. In this study, we performed a phylogeographic analysis to examine past changes in the distribution of A.serrata following climate oscillations during the Pleistocene. To cover most of A.serrata's range, leaves were collected from eight to ten individuals randomly selected from each of 37 populations in the Japanese Archipelago. Two chloroplast noncoding regions of the samples were amplified and sequenced: trnT(GGU)-psbD and trnH(GUG)-psbA spacers. Twenty-five haplotypes were detected and distinguished by 31 substitutions. Four main haplotypes were observed in many populations distributed throughout the Japanese Archipelago. According to the genetic boundaries detected using the Monmonier algorithm, A.serrata is clustered into four groups, each including several populations: Hokkaido Island, northern mainland Honshu, central Japan, and western Japan. The boundaries, however, were not robust because all genetic parameters did not support the differentiation among groups. These results indicate the absence of an obvious geographic structure in the distribution of A.serrata, suggesting that this species has experienced a rapid range expansion in postglacial times.

    DOI: 10.1111/1442-1984.12072

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  • Deletion of the Transcriptional Regulator cyAbrB2 Deregulates Primary Carbon Metabolism in Synechocystis sp PCC 6803 査読

    Yuki Kaniya, Ayumi Kizawa, Atsuko Miyagi, Maki Kawai-Yamada, Hirofumi Uchimiya, Yasuko Kaneko, Yoshikata Nishiyama, Yukako Hihara

    PLANT PHYSIOLOGY   162 ( 2 )   1153 - 1163   2013年6月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:AMER SOC PLANT BIOLOGISTS  

    cyAbrB is a transcriptional regulator unique to and highly conserved among cyanobacterial species. A gene-disrupted mutant of cyabrB2 (sll0822) in Synechocystis sp. PCC 6803 exhibited severe growth inhibition and abnormal accumulation of glycogen granules within cells under photomixotrophic conditions. Within 6 h after the shift to photomixotrophic conditions, sodium bicarbonate-dependent oxygen evolution activity markedly declined in the Delta cyabrB2 mutant, but the decrease in methyl viologen-dependent electron transport activity was much smaller, indicating inhibition in carbon dioxide fixation. Decreases in the transcript levels of several genes related to sugar catabolism, carbon dioxide fixation, and nitrogen metabolism were also observed within 6 h. Metabolome analysis by capillary electrophoresis mass spectrometry revealed that several metabolites accumulated differently in the wild-type and mutant strains. For example, the amounts of pyruvate and 2-oxoglutarate (2OG) were significantly lower in the mutant than in the wild type, irrespective of trophic conditions. The growth rate of the Delta cyabrB2 mutant was restored to a level comparable to that under photoautotrophic conditions by addition of 2OG to the growth medium under photomixotrophic conditions. Activities of various metabolic processes, including carbon dioxide fixation, respiration, and nitrogen assimilation, seemed to be enhanced by 2OG addition. These observations suggest that cyAbrB2 is essential for the active transcription of genes related to carbon and nitrogen metabolism upon a shift to photomixotrophic conditions. Deletion of cyAbrB2 is likely to deregulate the partition of carbon between storage forms and soluble forms used for biosynthetic purposes. This disorder may cause inactivation of cellular metabolism, excess accumulation of reducing equivalents, and subsequent loss of viability under photomixotrophic conditions.

    DOI: 10.1104/pp.113.218784

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