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• Molecular and neurobiological analyses of the circatidal clock mechanism in the mangrove cricket Apteronemobius asahinai

  2014.03

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Published Papers 【 display / non-display 】

• Artificial light including blue-green wavelengths promotes growth of <i>Rachycentron canadum</i> with mRNA upregulation of appetite, growth and lipid synthesis

  Zhu, YF; Takekata, H; Yamauchi, C; Takemura, A

  FRONTIERS IN MARINE SCIENCE ( Frontiers in Marine Science )  13   2026.05 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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  Introduction Cues from light, including photoperiod, intensity, and wavelength, can all impact physiology in fish. This study investigated the effect of light wavelengths on growth performance in the cobia Rachycentron canadum , a commercially valuable species in tropical waters. Methods Juveniles were exposed to blue (BL, 466 nm peak), green (GL, 518 nm peak), or natural light (NL) for four weeks. Results Compared to NL, BL and GL significantly enhanced body weight (BW) by 27.6% and 23.2%, respectively, and increased specific growth rate (SGR) by approximately 24% and 23%, respectively. Transcript levels of key visual opsins were more highly upregulated by blue and green light in the diencephalon, compared to the retina, highlighting the importance of extraretinal photoreception in growth regulation. Comparison of transcript levels of various genes regulating appetite or lipogenesis showed a wavelength-dependent effect on growth stimulation in juvenile cobia. Green light influenced transcript levels of the appetite-stimulating peptide, neuropeptide Y ( npy ), in the brain, and growth hormone receptor ( ghr ) in the liver. Whereas blue light increased the transcript levels of an anorexigenic peptide, pro-opiomelanocortin ( pomc ), in the brain, and fatty acid synthase ( fas ) in the liver. Discussion These results align with adaptation to blue-green-dominated marine environment, emphasizing the valuable, non-invasive tool that spectral optimization can be in aquaculture.

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• Chilling induces prompt and synchronised hatching after obligatory diapause in the subtropical cricket <i>Cardiodactylus guttulus</i>

  Takekata, H; Satomura, K; Ogura, A; Takemura, A

  PHYSIOLOGICAL ENTOMOLOGY ( Physiological Entomology )  50 ( 2 ) 216 - 220   2025.06 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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• Discovery and identification of a novel yeast species, Hanseniaspora drosophilae sp. nov., from Drosophila in Okinawa, Japan

  Seike, T; Takekata, H; Kono, K; Sakata, N; Kotani, H; Furusawa, C; Matsuda, F

  INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ( International Journal of Systematic and Evolutionary Microbiology )  75 ( 2 )   2025 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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  Hanseniaspora, a genus of yeasts in which many species reproduce sexually, has attracted the attention of researchers because of its prevalence in diverse ecological niches. Building on our extensive collection efforts since 2020, three previously unknown yeast strains from wild Drosophila species trapped in ripe bananas in Okinawa, Japan, were isolated. Using a multifaceted approach, including physiological assessments and sequence analysis of the D1/D2 domain of the 26S LSU rRNA gene and the internal transcribed spacer (ITS) region, it was revealed that these strains are novel members of the genus Hanseniaspora. The three strains, JCM 36741T, JCM 36742 and JCM 36748, had identical sequences in their respective D1/D2 and ITS regions, justifying their classification as a single species. Moreover, the new species exhibited a remarkable degree of sequence divergence from its closest relatives, differing by 7 nucleotide substitutions (1.28%) in the D1/D2 domain, 29 nucleotide substitutions and 4 gaps (4.08%) in the ITS regions. These substantial sequence differences highlight the distinctiveness of this novel species in the genus Hanseniaspora. Further analysis revealed physiological characteristics that distinguished the new species from its closest relative, Hanseniaspora hatyaiensis (nom. inval.). These findings culminated in the proposed name Hanseniaspora drosophilae sp. nov., which recognizes the unique ecological niche within the Drosophila microbiota. By uncovering this novel species, this study not only adds to the growing body of knowledge on yeast diversity but also sheds light on the intricate ecological relationships that shape microbial communities. The implications of this discovery extend beyond taxonomic boundaries, inviting further exploration of the evolutionary dynamics and ecological significance of yeast-fly interactions. We propose accommodating H. drosophilae sp. nov. in the genus Hanseniaspora with JCM 36741T as the holotype. The MycoBank accession number is MB 853822.

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• Annual and lunar-cycle-related breeding rhythmicity in the acorn barnacle <i>Tetraclita kuroshioensis</i> Chan, Tsang &amp; Chu, 2007 (Cirripedia: Balanomorpha: Tetraclitidae) in Okinawa, Japan

  Aoi Katayama, Ee Suan Tan, Hiroki Takekata, Akihiro Takemura

  Journal of Crustacean Biology ( Oxford University Press (OUP) )  44 ( 2 )   2024.06 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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  Abstract We investigated the reproduction of the barnacle Tetraclita kuroshioensisChan, Tsang &amp; Chu, 2007 (Cirripedia: Thoracica: Tetraclitidae) at different heights in the intertidal zone in Okinawa, Japan with a focus on gonadal development, the brooding of eggs, and unhatched larvae, as well as the role of environmental factors in breeding rhythmicity. Histological observations collected around each full moon from September 2019 to October 2020 showed various stages of oocyte development in September and October 2019 and from March to September 2020, whereas mature testes were observed from April to October 2020. The breeding season of this species thus lasts for at least seven months under long-day conditions at a water temperature above 21 °C. Barnacles collected from three tidal levels on multiple occasions during April, August, and October 2020 displayed little vertical variation in their stage of ovarian development, but there was a noticeable difference in the percentage of brooding individuals in August and October, as well as an increased prevalence of brooding during the new-moon phase at the upper and middle tidal heights. Our findings indicate that larval release by T. kuroshioensis undergoes seasonal variation, apparently influenced by the cycles of lunar (major factor) and tide (minor factor) in their habitat.

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• <i>Yamadazyma</i><i> thunbergiae</i> sp. nov., a novel yeast species associated with Bengal clock vines and soil in Okinawa, Japan

  Seike, T; Takekata, H; Sakata, N; Furusawa, C; Matsuda, F

  INTERNATIONAL JOURNAL OF SYSTEMATIC AND EVOLUTIONARY MICROBIOLOGY ( International Journal of Systematic and Evolutionary Microbiology )  74 ( 10 )   2024 [ Peer Review Accepted ]

  Type of publication: Research paper (scientific journal)

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  Two strains, designated JCM 36746T and JCM 36749, were isolated from Bengal clock vine (Thunbergia grandiflora) and soil, respectively, in Okinawa, Japan. Analysis of the internal transcribed spacer (ITS) regions and D1/D2 domains of the large subunit rRNA gene sequences revealed identical sequences in both strains, indicating that they belong to the same species. Sequence analysis and physiological characterization identified these strains as representing a novel yeast species in the genus Yamadazyma. The sequence similarities of the concatenated ITS regions and D1/D2 domains indicated that JCM 36746T and JCM 36749 formed a well-supported distinct from closely related species belonging to the Yamadazyma clade, including Candida dendronema, C. diddensiae, C. germanica, C. kanchanaburiensis, C. naeodendra, C. vaughaniae, Y. akitaensis, Y. koratensis, Y. nakazawae, Y. philogaea, Y. phyllophila, Y. siamensis, Y. ubonensis, and three undescribed species, comprising Candida aff. naeodendra/diddensiae Y151, Candida sp. GE19S08, and Yamadazyma sp. strain NYNU 22830. The sequences of the D1/D2 domains and ITS regions differed in nucleotide substitutions by 1.51% and 2.57% or greater, respectively, from those of the previously described and undescribed related species. In addition, the physiological characteristics of the novel species were distinct from those of the closely related described species. On the basis of these findings, we propose the name Yamadazyma thunbergiae sp. nov. to classify this species within the genus Yamadazyma. The holotype used is JCM 36746T (ex-type strains CBS 18614 and NBRC 116657). The MycoBank accession number is MB 853823.

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Presentations 【 display / non-display 】

Presentations 【 display / non-display 】

• Automatic Behavioral Analysis of Barnacles

  2022.12  -  2022.12 

• Period expression pattePeriod expression pattern in the brain with growth of the tropical grouper,

  2022.12  -  2022.12 

• Circatidal Activity Rhythms of Fistulobalanus albicostatus on Okinawa Island

  2021.11  -  2021.11 

• Elucidation of the water pressure transduction in threespot wrasse

  2021.11  -  2021.11 

• Expression changes associated with oogenesis of sex steroid hormone synthase 17B-HSD in Acropora tenuis

  2021.09  -  2021.09 

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• JSC Academic Encouragement Award

  2023.09   Japanese Society for Chronobiology  

Grant-in-Aid for Scientific Research 【 display / non-display 】

Grant-in-Aid for Scientific Research 【 display / non-display 】

• Molecular Basis of the Circatidal Clock in an Insect

  Challenging research (sprout)

  Project Year: 2026.06  -  2028.03 

  Direct: 4,900,000 (YEN)  Overheads: 6,370,000 (YEN)  Total: 1,470,000 (YEN)

• Grant-in-Aid for Scientific Research(C)

  Project Year: 2023.04  -  2026.03 

  Direct: 3,700,000 (YEN)  Overheads: 4,810,000 (YEN)  Total: 1,110,000 (YEN)

• Interplay between nutrition and reproduction in the neuroendocrine network of fish under tropical monsoon environments

  International joint research accelerated Fund (International Collaboration strengthening)

  Project Year: 2020.10  -  2024.03 

  Direct: 14,400,000 (YEN)  Overheads: 4,320,000 (YEN)  Total: 18,720,000 (YEN)

• Interplay between nutrition and reproduction in the neuroendocrine network of fish under tropical monsoon environments

  Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))

  Project Year: 2020.10  -  2024.03 

  Direct: 14,400,000 (YEN)  Overheads: 18,720,000 (YEN)  Total: 4,320,000 (YEN)

• Interplay between nutrition and reproduction in the neuroendocrine network of fish under tropical monsoon environments

  Fund for the Promotion of Joint International Research (Fostering Joint International Research (B))

  Project Year: 2020.10  -  2024.03 

  Direct: 14,400,000 (YEN)  Overheads: 18,720,000 (YEN)  Total: 4,320,000 (YEN)

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SDGs 【 display / non-display 】