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Position |
Associate Professor |
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Research Field |
Life Science / Ecology and environment |
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Graduating School 【 display / non-display 】
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Tokyo Metropolitan University Faculty of Science Graduated
1998.4 - 2002.3
Graduate School 【 display / non-display 】
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Ehime University Graduate School, Division of Agricltural Sciences Doctor's Course Completed
2004.4 - 2008.2
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The University of Tokyo Graduate School, Division of Science Master's Course Completed
2002.4 - 2004.3
Campus Career 【 display / non-display 】
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KONAN UNIVERSITY Faculty of Science and Engineering Faculty of Science and Engineering Department of Biology Associate Professor
2014.4
External Career 【 display / non-display 】
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独立行政法人日本学術振興会
2011.4 - 2013.3
Country：Japan
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自然科学研究機構生理学研究所
2010.9 - 2011.3
Country：Japan
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自然科学研究機構基礎生物学研究所
2008.4 - 2010.8
Country：Japan
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独立行政法人日本学術振興会
2005.4 - 2007.3
Country：Japan
Papers 【 display / non-display 】
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Evolution of meconium removal from cocoons in ants
A. Gotoh, F. Ito, R. Mizuno, Y. Shimamoto, K. Kinomura, E. Katsura, R. Hashim
Insectes Sociaux 2023.8
Publisher：Springer Science and Business Media LLC
DOI： 10.1007/s00040-023-00926-3
Other Link： https://link.springer.com/article/10.1007/s00040-023-00926-3/fulltext.html
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Near-anoxia induces immobilization and sustains viability of sperm stored in ant queens Reviewed
Ayako Gotoh, Mika Takeshima, Ken-ichi Mizutani
Scientific Reports 13 ( 1 ) 2023.3
Authorship：Lead author, Corresponding author Publisher：Springer Science and Business Media LLC
Abstract
After copulation, insect females store sperm in a spermatheca for some duration until fertilization. At the beginning of their adult lives, ant queens can preserve numerous viable sperm cells from copulation for over ten years. However, the key factors influencing long-term sperm storage have not been identified. Here we show that the spermathecal environment is nearly anoxic, which induces sperm immobilization. Furthermore, mitochondrial respiratory inhibitors suppress sperm motility, suggesting that sperm immobilization may be caused by a shortage of ATP generated from only glycolysis under near-anoxic conditions. Sperm immobilization is not induced by acidification via glycolytic metabolism because the spermathecal fluid is not acidic. Finally, we show that artificial anoxic conditions rather than aerobic conditions sustain viable sperm cells. Therefore, near-anoxia is a key factor influencing long-term sperm storage in ant queens. The viability of sperm cells under artificial anoxia, however, is lower than that of those dissected immediately from queens. Moreover, the immotile sperm cells under more than 4 h of anoxia do not begin swimming after aerobic exposure, unlike those under anoxic conditions for less than 2 h. This finding indicates that factors other than anoxia are also necessary for long-term sperm preservation.DOI： 10.1038/s41598-023-29705-7
Other Link： https://www.nature.com/articles/s41598-023-29705-7
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Ayako Gotoh
bioRxiv 2022.11
Authorship：Lead author, Corresponding author Publisher：Cold Spring Harbor Laboratory
Ant queens can maintain a large number of sperm cells for over a decade after mating at the beginning of their adult lives until they die. This ability is prominent because sperm cells cannot maintain their fertilization ability long after ejaculation in animals; however, the cellular mechanisms remain unclear. Sperm cells are maintained in the female sperm storage organ, the spermatheca, which supplies a suitable environment for sperm cells. To reveal the molecular basis of the long-term sperm storage mechanisms in ant queens, protein profiles enriched in the spermathecal fluid relative to the hemolymph were identified inLasius japonicususing mass spectrometry-based proteomics. Proteins related to the extracellular matrix, antioxidant, metabolic pathways, proteases, and with uncharacterized functions were enriched in the spermathecal fluid relative to the hemolymph. These enriched proteins were shared with highly expressed genes previously detected by transcriptome analyses of the spermatheca in queens ofCrematogaster osakensisbelonging to a different subfamily thanL. japonicus. It is considered that the ability for long-term sperm storage has evolved in the early ant lineage; therefore, the common proteins identified in the two ant species are crucial for this ability.
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Ayako Gotoh, Mika Takeshima, Ken-ichi Mizutani
bioRxiv 2022.9
Publisher：Cold Spring Harbor Laboratory
Abstract
Insect females store sperm in a spermatheca after copulation for some duration to use it later for fertilisation. At the beginning of their adult lives, ant queens can preserve numerous viable sperm cells from copulation for over ten years. However, the key factors influencing long-term sperm storage have not been identified. Here we show that the spermathecal environment is near anoxic, which induces sperm immobilisation. Furthermore, mitochondrial respiratory inhibitors suppress sperm motility, suggesting that sperm immobilisation may be caused by a shortage of ATP generated from only glycolysis under near anoxic condition. Sperm immobilisation is not induced by acidification via glycolytic metabolism because the spermathecal fluid is not acidic. Finally, we show that artificial anoxic conditions rather than aerobic conditions sustain viable sperm cells. Therefore, near-anoxia is a key factor influencing long-term sperm storage in ant queens. The viability of sperm cells under artificial anoxia, however, is lower than of those dissected immediately from queens. Moreover, the immotile sperm cells under more than 4 h of anoxia do not begin swimming after aerobic exposure, unlike those that were in anoxic conditions for less than 2 h. This indicates that factors other than anoxia are also necessary for long-term sperm preservation. -
Morphology of immatures of the thelytokous ant, Monomorium triviale Wheeler (Formicidae: Myrmicinae: Solenopsidini) with descriptions of the extraordinary last-instar queen larvae Reviewed
NAOTO IDOGAWA, AYAKO GOTOH, SHIGETO DOBATA
Zootaxa 5105 ( 2 ) 253 - 268 2022.3
Publisher：Magnolia Press
The ant genus Monomorium is one of the most species-rich but taxonomically problematic groups in the hyperdiverse subfamily Myrmicinae. An East Asian species, M. triviale Wheeler, produces both reproductive queens and sterile workers via obligate thelytokous parthenogenesis. Here, we describe the immature forms of M. triviale based on light and scanning electron microscopy observations, with a note on the striking caste dimorphism in the last larval instar. The last-instar queen larvae were easily recognized by their large size, “aphaenogastroid” body shape, and rows of doorknob-like tubercles on the lateral and dorsal body surface. This type of queen-specific structure has not been found in ants in general, let alone congeneric species found in Japan. In stark contrast to the queen larvae, worker larvae showed a “pheidoloid” body shape and a body surface similar to other ants. The worker larvae were estimated to have three instars, consistent with previously described congeners. The pupae of both castes had no cocoon, a characteristic commonly described in other Myrmicinae species. In total, the developmental period from egg to adult worker averaged 59 days under 25°C. We discuss possible functions of the tubercles of queen larvae based on previous studies.
Books and Other Publications 【 display / non-display 】
Review Papers (Misc) 【 display / non-display 】
Grant-in-Aid for Scientific Research 【 display / non-display 】
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女王アリの長期間の精子貯蔵に関わる受精嚢内微小環境の解析
2020.4 - 2023.3
JSPS Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research(C)
後藤 彩子
社会性ハチ目昆虫では、女王は羽化後まもない時期にしか交尾しないため、この時に受け取った精子を体内の受精嚢の中に寿命が続く限り貯蔵する。本研究では、精子が貯蔵される微小空間である受精嚢リザーバー内の化学的な性質を調べた後、それらのどの因子が精子の生存に寄与するか、また、寄与するのであれば 具体的に精子の生理状態にどのように影響しているかを明らかにすることで、アリ科女王の長期間の精子貯蔵メカニズムの解明を目指している。 本年度は、微量な受精嚢リザーバー内液をサンプリングし、プロテオーム解析をすることに成功した。解析の結果、精子貯蔵に重要だと思われるタンパク質候補を絞り込むことができた。また、これまでに、貯蔵中の精子は不動化されていることがわかっている(Gotoh and Furukawa, 2018)。昨年度に各種試薬や阻害剤を使用することで、精子の不動化に関与する要素をほぼ特定することができたが、本年度ではそれをさらに補強するデータがとれた。これらのデータをまとめ、現在論文を執筆している。