Using the Acropora digitifera genome to understand coral responses to environmental change

Despite the enormous ecological and economic importance of coral reefs, the keystone organisms in their establishment, the scleractinian corals, increasingly face a range of anthropogenic challenges including ocean acidification and seawater temperature rise1, 2, 3, 4. To understand better the molecular mechanisms underlying coral biology, here we decoded the approximately 420-megabase genome of Acropora digitifera using next-generation sequencing technology. This genome contains approximately 23,700 gene models. Molecular phylogenetics indicate that the coral and the sea anemone Nematostella vectensis diverged approximately 500 million years ago, considerably earlier than the time over which modern corals are represented in the fossil record (~240 million years ago)5. Despite the long evolutionary history of the endosymbiosis, no evidence was found for horizontal transfer of genes from symbiont to host. However, unlike several other corals, Acropora seems to lack an enzyme essential for cysteine biosynthesis, implying dependency of this coral on its symbionts for this amino acid. Corals inhabit environments where they are frequently exposed to high levels of solar radiation, and analysis of the Acropora genome data indicates that the coral host can independently carry out de novo synthesis of mycosporine-like amino acids, which are potent ultraviolet-protective compounds. In addition, the coral innate immunity repertoire is notably more complex than that of the sea anemone, indicating that some of these genes may have roles in symbiosis or coloniality. A number of genes with putative roles in calcification were identified, and several of these are restricted to corals. The coral genome provides a platform for understanding the molecular basis of symbiosis and responses to environmental changes

深海化学合成二枚貝における共生細菌の次世代伝達系

http://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt11-09/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt13-07/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt14-05/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt10-08/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt07-08/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt14-06/

シマイシロウリガイのユニークな共生細菌伝達機構

http://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt13-07/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt14-05/ehttp://www.godac.jamstec.go.jp/darwin/cruise/natsushima/nt11-09/

R/V Shinsei Maru Cruise Report KS-20-1

調査海域: 相模湾, 明神海丘 / Area: Off Hatsushima, Myojin Knoll ; 期間: 2020年1月6日～2020年1月11日 / Operation Period: January 6, 2020～January 11, 2020http://www.godac.jamstec.go.jp/darwin/cruise/shinsei_maru/ks-20-1/

Occurrence of polybrominated diphenyl ethers and benzotriazole UV stabilizers in the hadal amphipod Hirondellea gigas

Summary: The accumulation of polybrominated diphenyl ethers (PBDEs) and benzotriazole UV stabilizers (BZT-UVs) were examined in the hadal amphipod Hirondellea gigas caught from a near-land trench off the Japan island (9200 m). H. gigas were collected from two distinct sites: one is located at the outlet of submarine canyons directly connected to land and the other is apart from the outlet and geographically isolated from the first site. The level of the PBDEs in H. gigas at the canyon outlet (mean 219 ng/g lipid weight (l.w.)) was significantly higher than that in the isolated site (mean 42 ng/g l.w.) and BZT-UVs were only detected within the first site (mean 1.5 ng/g wet weight). In addition to vertical transport from the surface water, near-land trenches associated with submarine canyons and troughs may have more complex influx of contaminants through horizontal transportation from the land, resulting in more severe contamination

DataSheet_1_Accumulation of polychlorinated biphenyls in the ovaries of deep-sea chemosynthetic clam Phreagena okutanii.pdf

Polychlorinated biphenyls (PCBs) persistently pollute marine ecosystems even though their production has been discontinued decades ago. Deep-sea organisms have been shown to accumulate PCBs and other persistent organic compounds; however, the extent of contamination and its effects remain poorly understood. Here, we measured PCB concentrations in separated organs of non-feeding bivalve clams belonging to Phreagena, a taxon representative of deep-sea chemosynthetic ecosystems. The highest concentrations of PCBs were detected in the ovaries. We also examined surface sediments of the clam habitat and observed concentrations comparable to those in the sediments of the seas around Japan, including shallow waters. The results showed that PCBs from the environment penetrate Phreagena clams through the body surface and accumulate in the female reproductive system. This raises concerns about a potentially severe direct impact on the survival of vulnerable and highly endemic deep-sea chemosynthetic bivalves.</p