唾を吐くコブラの痛みを誘発する防御毒成分の収束進化
T D Kazandjian1, D Petras2,3, S D Robinson4,5
1Centre for Snakebite Research and Interventions, Liverpool School of Tropical Medicine, Liverpool L3 5QA, UK.
まとめ
コブラの収束進化は 3つの系統が 独立して 吐き毒を進化させたことを示しています この防御メカニズムは フォスフォリファーゼA2の毒素を増加させ 敵の痛みを増幅します
科学分野:
- 進化生物学
- 生物化学
- 動物学
背景:
- 収束進化は,異なる系統で,どのように類似した特徴が独立して生じるかを示しています.
- 蛇の毒は,遺伝的基礎と機能的な現象型による適応の進化を研究するためのモデルシステムを提供します.
- ほとんどのヘビは 捕食のために毒を使用しますが 防御的な毒の使用戦略を 進化させたものもいます
研究 の 目的:
- 3つの異なるコブラの系統で 毒を吐き出すという 進化のメカニズムを調査する
- 毒を吐き出すと 毒の成分が変化する 遺伝的・生化学的根拠を分析する
- 防御的な文脈で毒の組成の変化の 機能的な結果を理解する.
主な方法:
- 唾を吐くコブラと 唾を吐かないコブラの毒を比較したゲノムとタンパク質分析
- 毒成分,特にフォスフォリファースA2 (PLA2) 毒素の酵素活性と機能特性を特徴付ける生化学的測定.
- 感覚神経と痛みの経路に対する毒の影響を評価する in vitroおよびin vivoの機能研究.
主要な成果:
- 3つの独立したコブラの系統が 毒を吐き出すことを進化させたのです
- 唾を吐くコブラは 毒素であるフォスフォリファースA2 (PLA2) の濃度が大幅に上昇しています
- 高濃度のPLA2毒素は既存の細胞毒素を強化し,哺乳類の感覚神経細胞の活性化と痛みの増加につながります.
結論:
- 毒を吐くコブラの進化は 複数の表型レベルで収束する進化の 顕著な例です
- PLA2の毒素は 毒素の機能を変化させ
- この研究は 既存の毒素の成分が どのように再利用され 改良され 新しい防御能力を 進化させるかを強調しています
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