Katsuyuki Uematsu

Isolation of an archaeon at the prokaryote eukaryote interface

Hiroyuki Imachi, Masaru Konishi Nobu, Nozomi Nakahara, Yuki Morono et autres

This dataset contains the digitized treatments in Plazi based on the original journal article Imachi, Hiroyuki, Nobu, Masaru K., Nakahara, Nozomi, Morono, Yuki, Ogawara, Miyuki, Takaki, Yoshihiro, Takano, Yoshinori, Uematsu, Katsuyuki, Ikuta, Tetsuro, Ito, Motoo, Matsui, Yohei, Miyazaki, Masayuki, Murata, Kazuyoshi, Saito, …

Closer to the native state: Sandwich freezing and freeze‐substitution of microorganisms, cultured cells, and animal and plant tissues for electron microscopy

Masashi Yamaguchi, Katsuyuki Uematsu, Toshikatsu Kuramoto, Shinichi Ohno et autres

Since the invention of the electron microscope, morphologists have developed numerous techniques to visualise the native ultrastructure of biological cells and tissues. Although conventional chemical fixation followed by room temperature dehydration remains widely used, it often fails to preserve native structures, leading …

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Different Elemental Compositions and Potential Functions of Vacuoles in Bolivina spissa (Foraminifera, Rhizaria) Based on Cryo‐SEM‐EDS Analyses

Julien Richirt, Satoshi Okada, Yoshiyuki Ishitani, Nicolaas Glock et autres

ABSTRACT Benthic Foraminifera exhibit diverse adaptations to low oxygen (O 2 ) environments, including denitrification, a rare trait among eukaryotes. Denitrifying species store intracellular nitrate (NO 3 − ), possibly within vacuoles, and contribute significantly to the global marine nitrogen (N) cycle. …

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Keratinization-like differentiation process forms chitinous dermal sclerites in the hot-vent snail Ifremeria nautilei

Chong Chen, Satoshi Okada, Hiromi Watanabe, Katsuyuki Uematsu et autres

Animals produce diverse hard structures for critical functions such as protection, feeding and detoxification. Most animals use the polysaccharide chitin as a framework for this, while vertebrates have switched to using fibrous proteins like collagen and keratin. Vertebrates make structures like skin …

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Author response for "Keratinization-like differentiation process forms chitinous dermal sclerites in the hot-vent snail Ifremeria nautilei"

Chong Chen, Satoshi Okada, Hiromi Watanabe, Katsuyuki Uematsu et autres

Eukaryotes’ closest relatives are internally simple syntrophic archaea

Hiroyuki Imachi, Masaru Konishi Nobu, Shun’ichi Ishii, Yuga Hirakata et autres

Abstract Eukaryotes are theorized to have originated from an archaeal phylum Promethearchaeota (formerly ‘Asgard’ archaea) 1,2 . The first cultured representatives revealed valuable insight 3,4 but are distantly related to the first eukaryotic common ancestor (FECA), leaving many unknowns regarding this archaeon’s …

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Oceanic Biodegradation Mechanisms of Chemosynthetic Biodegradable Polyesters: Focusing on Poly(butylene succinate-co-adipate)

Miwa Suzuki, Shun’ichi Ishii, Kohei Gonda, Hiroyuki Kashima et autres

High Resolution Image Download MS PowerPoint Slide To address marine plastic pollution, biodegradable plastics have been proposed. However, chemosynthetic biodegradable polyesters exhibit lower marine biodegradability than biosynthetic polyesters, limiting their utility. We elucidated why chemosynthetic polyesters exhibit this lower biodegradability, using an …

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Composite calcite and opal test in Foraminifera (Rhizaria)

Julien Richirt, Satoshi Okada, Yoshiyuki Ishitani, Katsuyuki Uematsu et autres

Foraminifera are unicellular eukaryotes known to have a shell, called a test, generally made of secreted calcite (CaCO 3 ). For the first time, we report a foraminifera with a composite calcite–opal test in the cosmopolitan and well-studied benthic species Bolivina spissa …

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Promethearchaeum syntrophicum gen. nov., sp. nov., an anaerobic, obligately syntrophic archaeon, the first isolate of the lineage ‘Asgard’ archaea, and proposal of the new archaeal phylum Promethearchaeota phyl. nov. and kingdom Promethearchaeati regn. nov.

Hiroyuki Imachi, Masaru Konishi Nobu, Shingo Kato, Yoshihiro Takaki et autres

An anaerobic, mesophilic, syntrophic, archaeon strain MK-D1 T , was isolated as a pure co-culture with Methanogenium sp. strain MK-MG from deep-sea methane seep sediment. This organism is, to our knowledge, the first cultured representative of ‘Asgard’ archaea, an archaeal group closely …

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Foraminiferal detoxification breakdown induced by fatal levels of TiO2 nanoparticles

Yuka Inagaki, Yoshiyuki Ishitani, Akihiro Tame, Katsuyuki Uematsu et autres

The increase discharge of titanium dioxide (TiO2) nanoparticles, derived from engineered material waste, exerts a detrimental impact on both the marine ecosystem and public health. The cytotoxicity of TiO2 nanoparticles on marine organisms should be imperatively understood to tackle the urgent concern …

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Comment on egusphere-2024-60

Julien Richirt, 聡 岡田, Yoshiyuki Ishitani, Katsuyuki Uematsu et autres

Abstract. Foraminifera are unicellular eukaryotes known to have a shell, called test, generally made of secreted calcite (CaCO3). We report for the first time a Foraminifera having a composite calcite/opal test in the cosmopolitan and well-studied benthic species Bolivina spissa (Rotaliida), sampled …

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The calcitic test growth rate of Spirillina vivipara (Foraminifera)

Yukiko Nagai, Katsuyuki Uematsu, Briony Mamo, Takashi Toyofuku

Foraminifera encompass vastly differing morphologies, ecological preferences, and elemental/isotopic test compositions. The calcification mechanism is completely unknown for some wall-type taxa and might be different from that of well-studied groups. This study aims to understand the test growth and determine the calcification …

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