Possible Roles of Hypotaurine and Thiotaurine in the Vesicomyid Clam<i>Phreagena okutanii</i>

Kuroda, Megumi; Nagasaki, Toshihiro; Koito, Tomoko; Hongo, Yuki; Yoshida, Takao; Maruyama, Tadashi; Tsuchida, Shinji; Nemoto, Suguru; Inoue, Koji

doi:10.1086/712396

Cited by 3 publications

(1 citation statement)

References 38 publications

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“…Hypotaurine, a substance similar to taurine, and hydrogen sulfide ion can be converted to thiotaurine, a nontoxic substance that can be passed to symbionts (Pruski and Fiala-Médioni 2003;Yancey 2005;Koito et al 2010;Nagasaki et al 2018;Kuroda et al 2021). As mussels are always exposed to sulfides in hydrothermal-vent water, gill cells must maintain high hypotaurine levels.…”

Section: Hypotaurine Of Deep-sea Musselsmentioning

confidence: 99%

Mussel biology: from the byssus to ecology and physiology, including microplastic ingestion and deep-sea adaptations

2021

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Mussels are a group of bivalves that includes the dominant species of shallow-sea, freshwater, and deep-sea chemosynthetic ecosystems. Mussels cling to various solid underwater surfaces using a proteinaceous thread, called the byssus, which is central to their ecology, physiology, and evolution. Mussels cluster using their byssi to form “mussel beds,” thereby increasing their biomass per unit of habitat area, and also creating habitats for other organisms. Clustered mussels actively filter feed to obtain nutrients, but also ingest pollutants and suspended particles; thus, mussels are good subjects for pollution analyses, especially for microplastic pollution. The byssus also facilitates invasiveness, allowing mussels to hitchhike on ships, and to utilize other man-made structures, including quay walls and power plant inlets, which are less attractive to native species. Physiologically, mussels have adapted to environmental stressors associated with a sessile lifestyle. Osmotic adaptation is especially important for life in intertidal zones, and taurine is a major component of that adaptation. Taurine accumulation systems have also been modified to adapt to sulfide-rich environments near deep-sea hydrothermal vents. The byssus may have also enabled access to vent environments, allowing mussels to attach to “evolutionary stepping stones” and also to vent chimneys.

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Section: Hypotaurine Of Deep-sea Musselsmentioning

confidence: 99%

Mussel biology: from the byssus to ecology and physiology, including microplastic ingestion and deep-sea adaptations

2021

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Heterologous expression and functional characterization of cysteamine dioxygenase from the deep-sea mussel Bathymodiolus septemdierum

et al. 2023

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In invertebrates inhabiting hydrothermal vent areas, hypotaurine, a precursor of taurine, is thought to mitigate the toxicity of hydrogen sulfide in vent fluids. Information about hypotaurine synthesis pathways in invertebrates is limited, although two pathways, the cysteamine [2-aminoethanethiol (AET)] pathway and the cysteine sulfinate (CSA) pathway are known in mammals. In this study, we cloned a cDNA encoding AET dioxygenase (ADO), the central enzyme of the AET pathway, from the vent mussel Bathymodiolus septemdierum. In the encoded protein (BsADO), functionally important residues, including metal-binding histidines, are conserved. In maximum likelihood phylogenetic analysis, BsADO clustered with ADOs of other invertebrates. By reverse transcription PCR, BsADO mRNA was detected in all tissues examined at similar levels, suggesting that its function is distinct from that of the CSA pathway, predominantly expressed in the gill. BsADO with a His tag, expressed in Escherichia coli in the presence of Fe2+, converted AET to hypotaurine, but BsADO expressed in the absence of iron exhibited lower activity. BsADO was active from pH 8 to 11, and from 0 °C to 37 °C, with a peak at 20 °C. This is the first functional characterization of ADO in marine invertebrates.

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Identification and expression of cysteine sulfite decarboxylase genes and their response to hyposalinity stress in Ruditapes philippinarum

et al. 2023

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Cysteine sulfinate decarboxylase (CSAD) is a rate-limiting enzyme in taurine biosynthesis. In this study, the structure and expression characteristics of the RpCSAD gene in Ruditapes philippinarum were analyzed. The pyridoxal phosphate (PLP)-dependent amino acid carboxylase structural domains and catalytic active sites of six copies of RpCSAD were highly conserved. Tissue expression analysis demonstrated that RpCSAD1 and RpCSAD3-6 was primarily expressed in the mantle tissue, and RpCSAD2 in the water tube and gonad tissue. After exposure to hyposalinity stress, the expression levels of RpCSADs were found to be upregulated in all three shell-colored groups of clams. Remarkably, there was a pronounced increase in the expression of RpCSAD1-6 observed specifically in the zebra shell-color groups. These findings strongly suggest the involvement of taurine metabolism in the response of zebra shell-color clams to low salinity stress, thereby emphasizing its critical role in the adaptation mechanisms. These findings could contribute to a better understanding the mechanisms of osmotic stress tolerance in shellfish.

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Possible Roles of Hypotaurine and Thiotaurine in the Vesicomyid ClamPhreagena okutanii

Cited by 3 publications

References 38 publications

Mussel biology: from the byssus to ecology and physiology, including microplastic ingestion and deep-sea adaptations

Mussel biology: from the byssus to ecology and physiology, including microplastic ingestion and deep-sea adaptations

Heterologous expression and functional characterization of cysteamine dioxygenase from the deep-sea mussel Bathymodiolus septemdierum

Identification and expression of cysteine sulfite decarboxylase genes and their response to hyposalinity stress in Ruditapes philippinarum

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