Author Inoue, Mayuri| Nakamura, Takashi| Tanaka, Yasuaki| Suzuki, Atsushi| Yokoyama, Yusuke| Kawahata, Hodaka| Sakai, Kazuhiko| Gussone, Nikolaus|
Abstract Light-enhanced calcification of reef-building corals, which eventually create vast coral reefs, is well known and based on coral-algal symbiosis. Several controversial hypotheses have been proposed as possible mechanisms for connecting symbiont photosynthesis and coral calcification, including pH rise in the internal pool, role of organic matrix secretion, and enzyme activities. Here, based on the skeletal chemical and isotopic compositions of symbiotic and asymbiotic primary polyps of Acropora digitifera corals, we show a simple pH increase in the calcification medium as the predominant contribution of symbionts to calcification of host corals. We used the symbiotic and asymbiotic primary polyps reared for 10 days at four temperatures (27, 29, 31, and 33 °C), five salinities (34, 32, 30, 28, and 26), and four pCO2 levels (<300, 400, 800, and 1000 µatm). As a result of analyzing multiple geochemical tracers (U/Ca, Mg/Ca, Sr/Ca, δ18O, δ13C, and δ44Ca), a clear and systematic decrease in skeletal U/Ca ratio (used as a proxy for calcification fluid pH) was observed, indicating a higher pH of the fluid in symbiotic compared to asymbiotic polyps. In contrast, Mg/Ca ratios (used as a tentative proxy for organic matrix secretion) and δ44Ca (used as an indicator of Ca2+ pathway to the fluid) did not differ between symbiotic and asymbiotic polyps. This suggests that organic matrix secretion related to coral calcification is controlled mainly by the coral host itself, and a transmembrane transport of Ca2+ does not vary according to symbiosis relationship. Skeletal δ18O values of both symbiotic and asymbiotic polyps showed offsets between them with identical temperature dependence. Based on a newly proposed model, behavior of δ18O in the present study seems to reflect the rate of CO2 hydration in the calcifying fluid. Since CO2 hydration is promoted by enzyme carbonic anhydrase, the offset of δ18O values between symbiotic and asymbiotic polyps is attributed to the differences of enzyme activity, although the enzyme is functional even in the asymbiotic polyp. Symbiotic δ13C values in the temperature and salinity experiments were higher compared to those in the asymbiotic polyps due to photosynthesis, although photosynthetic δ13C signals in the pCO2 experiment were masked by the dominant δ13C gradient in dissolved inorganic carbon in seawater caused by 13C-depletd CO2 gas addition in the higher pCO2 treatments. Sr/Ca ratios showed a negligible relationship according to variation of temperature, salinity, and pCO2, although it might be attributed to relatively large deviations of replicates of Sr/Ca ratios in the present study. Overall, only the U/Ca ratio showed a significant difference between symbiotic and asymbiotic polyps throughout all experiments, indicating that the critical effect on coral calcification caused by symbiotic algae is the increase of pH of the calcifying fluid by photosynthesis.
Keywords Coral symbiosis calcification pH geochemical tracers
Note This is an Accepted Manuscript of an article published by Elsevier B.V. This fulltext will be available in May 2020
Published Date 2018-08-15
Publication Title Geochimica et Cosmochimica Acta
Volume volume235
Publisher Elsevier B.V.
Start Page 76
End Page 88
ISSN 00167037
NCID AA00655038
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
File Version author
DOI 10.1016/j.gca.2018.05.016
Related Url isVersionOf https://doi.org/10.1016/j.gca.2018.05.016
Author Okada, Masahiro| Nakai, Akira| Hara Emilio, Satoshi| Taguchi, Tetsushi| Nakano, Takayoshi| Matsumoto, Takuya|
Abstract Over the past few years, the development of novel adhesives for biological soft tissue adhesion has gained significant interest. Such adhesives should be non-toxic and biocompatible. In this study, we synthesized a novel solid adhesive using nanostructured hydroxyapatite (HAp) and evaluated its physical adhesion properties through in vitro testing with synthetic hydrogels and mouse soft tissues. The results revealed that HAp-nanoparticle dispersions and HAp-nanoparticle-assembled nanoporous plates showed efficient adhesion to hydrogels. Interestingly, the HAp plates showed different adhesive properties depending upon the shape of their nanoparticles. The HAp plate made up of 17 nm-sized nanoparticles showed an adhesive strength 2.2 times higher than that of the conventional fibrin glue for mouse skin tissues.
Keywords Hydroxyapatite Nanoparticle Solid adhesive Wet adhesion
Note 2019年6月公開予定
Published Date 2017-05
Publication Title Acta Biomaterialia
Publisher Elsevier B.V.
ISSN 1742-7061
NCID AA12033647
Content Type Journal Article
language 英語
OAI-PMH Set 岡山大学
Copyright Holders © 2017. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/
File Version author
PubMed ID 28483692
Related Url https://doi.org/10.1016/j.actbio.2017.05.014
Author Monden, Yuki| Takasaki, Kazuto| Futo, Satoshi| Niwa, Kousuke| Kawase, Mitsuo| Akitake, Hiroto| Tahara, Makoto|
Published Date 2014-09-20
Publication Title Journal of Biotechnology
Volume volume185
Content Type Journal Article
Author Taguchi, Hideki| Yamasaki, Satoshi| Itadani, Atsushi| Yosinaga, Masashi| Hirota, Ken|
Published Date 2008-05-15
Publication Title Catalysis Communications
Volume volume9
Issue issue9
Content Type Journal Article
Author Amin, Md. Ziaul| Bando, Tetsuya| Ruksana, Razia| Anokye-Danso, Frederick| Takashima, Yasuo| Sakube, Yasuji| Kagawa, Hiroaki|
Published Date 2007-04
Publication Title Biochimica et Biophysica Acta. Proteins and Proteomics
Volume volume1774
Issue issue4
Content Type Journal Article
Author Teraishi, Fuminori| Kagawa, Shunsuke| Watanabe, Takanori| Tango, Yasuhisa| Kawashima, Takeshi| Umeoka, Tatsuo| Nisizaki, Masahiko| Tanaka, Noriaki| Fujiwara, Toshiyoshi|
Published Date 2005-08-01
Publication Title FEBS Letters
Volume volume579
Issue issue19
Content Type Journal Article
Author Kurauchi, Tomomi| Yokota, Kenji| Matsuo, Toshihiko| Fujinami, Yoshihito| Isogai, Emiko| Isogai, Hiroshi| Ohtsuki, Hiroshi| Oguma, Keiji|
Published Date 2005-02-01
Publication Title FEMS Immunology and Medical Microbiology
Volume volume43
Issue issue2
Content Type Journal Article