海洋酸化对泥蚶精子运动的影响及作用机理初探

研究分析了未来海洋酸化情景(pH7.8和pH7.4)对典型滩涂贝类泥蚶(Tegillarca granosa)精子运动活力的影响, 并从精子运动供能角度探究了其作用机理。研究结果表明, 海洋酸化可以显著削弱泥蚶的精子运动速度。由于精子的三磷酸腺苷(ATP)水平与其活力呈显著的正相关, 研究检测了不同酸化条件下泥蚶精子的ATP含量及其合成关键酶酶活, 实验结果显示精子的ATP含量以及磷酸果糖激酶和丙酮酸激酶活力在酸化条件下均显著下降。此外, 精子内的Ca2+-ATP酶(Ca2+-ATPase)调节了精子的运动能力, 因此实验也探究了海洋酸化对泥蚶精子Ca2+-ATPase酶活的影响, 结果证实该酶活力在海水pH为7.4时被显著抑制。综合本研究结果可以得出, 海洋酸化很可能会通过干扰精子细胞内ATP的合成及Ca2+的调控进而削弱精子的运动速度。

OCEAN ACIDIFICATION INHIBITS THE SPERM MOTILITY OF TEGILLARCA GRANOSA VIA DISUTRBING ATP SYNTHESIS AND INTRACELLULAR CA2+ ACTIVITY

Since the industrial revolution, massive amount of anthropogenic carbon dioxide (CO₂) have been generated to elevate the atmospheric CO₂ concentration. Some anthropogenic CO₂ have been absorbed by the ocean to cause “ocean acidification” (OA). Although the negative impacts of OA on sperm motility are increasingly found in various marine invertebrate species, the cellular and molecular mechanisms for these effects are still poorly understood. This study investigated the effect of OA (pH7.8 and 7.4) on sperm motility and energy supplying pathway in blood clam Tegillarca granosa. The results showed that the sperm swimming speed reduced significantly in acidified seawater. Since the adenosine triphosphate (ATP) level of sperm is closely related to its motility, we analyzed the sperm ATP content and activities of key enzymes during ATP synthesis under different OA scenarios. OA treatments significantly reduced ATP content as well as activities of 6-phosphofructokinase and pyruvate kinase in the sperm of T. granosa. The sperm Ca2+-ATPase of various animals has been reported to regulate sperm motility. Therefore, we explored the Ca2+-ATPase activity of T. granosa sperm under OA treatment. The results found that Ca2+-ATPase activities in the sperm of T. granosa were significantly declined under OA scenarios. In conclusion, these results suggested that OA could constrain sperm motility through inhibiting ATP synthesis and disturbing intracellular Ca2+ regulation.