動的な細胞応答がシネコシスティスの亜致死濃度カドミウムストレスへの適応を明らかにする(Study Reveals Dynamic Cellular Responses of Synechocystis to Sublethal Cadmium Stress)

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2026-08-07 中国科学院(CAS)

シアノバクテリアのSynechocystis sp. PCC 6803が、環境中で想定される低濃度のカドミウム(Cd²⁺)に長期間さらされた際の細胞応答を解析した研究。中国科学院水生生物研究所の研究チームは、0.05 mg/LのCd²⁺を0.5~144時間曝露し、24時間を境に応答が「急性ストレス応答」から「長期適応」へ移行することを明らかにした。初期には金属センシング、光化学系修復、窒素・グルタミン酸代謝が活性化し、適応期には145個の共通差次的発現タンパク質が安定した制御モジュールを形成した。さらに、MntCABやFeoBによる金属取り込みを抑制する一方、Slr0944、ZiaA、Sll1725などの排出系を誘導し、TCA回路やエネルギー代謝、抗酸化防御を強化して細胞恒常性を維持していた。これらの知見は、シアノバクテリアのカドミウム適応機構の理解や生物学的浄化への応用に寄与すると期待される。


Schematic illustration of the two-stage response model of Synechocystis sp. PCC 6803 under low-level cadmium stress. (Image by IHB)

<関連情報>

時間分解マルチオミクスにより、Synechocystis sp. PCC 6803のカドミウムストレスに対する分子ダイナミクスが明らかになった Time-resolved multi-omics reveals molecular dynamics of Synechocystis sp. PCC 6803 to cadmium stress

Gang Ruan, Xiaohan Ai, Shaoqiang Sun, Jing Qian, Gaofei Song, Wujuan Mi, Dong Wan, Yonghong Bi
Environmental Pollution  Available online: 18 June 2026
DOI:https://doi.org/10.1016/j.envpol.2026.128590

Highlights

  • Cyanobacteria employ a biphasic molecular strategy.
  • Temporal multi-omics reveals response-phase and adaptation-phase.
  • Response phase activates cation efflux and glutamine synthetase.
  • Adaptation phase dynamically regulates transporters and antioxidant enzymes.

Abstract

Cadmium pollution posed a serious threat to eco-environmental security, but molecular variation in microalgae induced by cadmium remains unknown. To address this, we screened the molecular dynamics in Synechocystis sp. PCC 6803 exposed to an environmentally relevant Cd2+ concentration (0.05 mg L−1) over 0–144 h. Differential express genes/proteins (DEGs/DEPs) and expression levels divided the exposure process into two stages. The response phase (0–24 h) was characterized by the rapid, transient, and highly specific gene/protein activation; the top uniquely DEGs/DEPs included nrsA (cation-efflux), PsbA1/T (Photosystem II protein) and Ssl1911 (glutamine synthetase) were defined as stage-specific molecular signatures. Their expression peaked before 24 h and showed no significant change thereafter. The adaptive phase (24–144 h) was characterized by the sustained and synergistic proteomic dynamic regulation, 145 co-expressed DEPs were identified, cadmium influx-associated transporters (MntCAB/FeoB) were suppressed, efflux systems (Slr0944/ZiaA) were induced coupled with enhanced central carbon metabolism (carbon fixation, oxidative phosphorylation, TCA cycle) and elevated antioxidant enzyme activity (Slr1516). It was concluded DEGs/DEPs involved in photosynthetic processes and antioxidant defense changed significantly within 24 h. These changes were followed by adaptive mechanisms, including down-regulating inward Cd2+ transporters while simultaneously up-regulating efflux pumps, as well as enhancing energy metabolism and antioxidant capacity. This dynamic pattern provided insight into the interaction between cyanobacterial cells and cadmium ions.

生物環境工学
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