著者

Susumu Yoshizawa Tomonori Azuma Keiichi Kojima Keisuke Inomura Masumi Hasegawa Yosuke Nishimura Masuzu Kikuchi Gabrielle Armin Yuya Tsukamoto Hideaki Miyashita Kentaro Ifuku Takashi Yamano Adrian Marchetti Hideya Fukuzawa Yuki Sudo Ryoma Kamikawa

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.38, no.2, pp.ME23015, 2023 (Released:2023-06-20)

参考文献数

46

被引用文献数

4

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Diatoms are a major phytoplankton group responsible for approximately 20% of carbon fixation on Earth. They perform photosynthesis using light-harvesting chlo­rophylls located in plastids, an organelle obtained through eukaryote-eukaryote endosymbiosis. Microbial rhodopsin, a photoreceptor distinct from chlo­rophyll-based photosystems, was recently identified in some diatoms. However, the physiological function of diatom rhodopsin remains unclear. Heterologous expression techniques were herein used to investigate the protein function and subcellular localization of diatom rhodopsin. We demonstrated that diatom rhodopsin acts as a light-driven proton pump and localizes primarily to the outermost membrane of four membrane-bound complex plastids. Using model simulations, we also examined the effects of pH changes inside the plastid due to rhodopsin-mediated proton transport on photosynthesis. The results obtained suggested the involvement of rhodopsin-mediated local pH changes in a photosynthetic CO2-concentrating mechanism in rhodopsin-possessing diatoms.

著者

Satoshi Ohkubo Hideaki Miyashita

出版者

Japanese Society of Microbial Ecology / Japanese Society of Soil Microbiology / Taiwan Society of Microbial Ecology / Japanese Society of Plant Microbe Interactions / Japanese Society for Extremophiles

雑誌

Microbes and Environments (ISSN:13426311)

巻号頁・発行日

vol.27, no.3, pp.217-225, 2012 (Released:2012-09-06)

参考文献数

27

被引用文献数

11 13

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Acaryochloris spp. are unique cyanobacteria which contain chlorophyll d as the predominant pigment. The phylogenetic diversity of Acaryochloris spp. associated with 7 Prochloron- or Synechocystis-containing didemnid ascidians and 1 Synechococcus-containing sponge obtained from the coast of the Republic of Palau was analyzed; we established a PCR primer set designed to selectively amplify the partial 16S rRNA gene of Acaryochloris spp. even in DNA samples containing a large amount of other cyanobacterial and algal DNAs. Polymerase chain reaction-denaturing gradient gel electrophoresis with this primer set enabled detection of the phyogenetic diversity of Acaryochloris spp. All the ascidian and sponge samples contained Acaryochloris spp. Fourteen phylotypes that were highly homologous (98–100%) with A. marina MBIC11017 were detected, while only 2 phylotypes were detected with our previously developed method for detecting cyanobacteria. The results also revealed that many uncultured phylotypes of Acaryochloris spp. were associated with those didemnid ascidians, since a clonal culture of only 1 phylotype has been established thus far. No specific relationship was found among the Acaryochloris phylotypes and the genera of the ascidians even when sample localities were identical; therefore, these invertebrates may provide a favorable habitat for Acaryochloris spp. rather than hosts showing any specific symbiotic relationships.