Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
Department of Biological and Environmental Sciences, Le Moyne College, Syracuse, NY 13214, USA.
Integr Comp Biol. 2024 Sep 17;64(2):414-423. doi: 10.1093/icb/icae068.
The mussel Mytilus californianus is an ecosystem engineer forming beds along the coastlines of Northeastern Pacific shores. As sessile organisms, they modulate their energy balance through valve movements, feeding, and digestive functionality. A recent study observed that activity of the digestive enzyme cellulase was higher than predicted in mussels high on the shore, where temperatures are characteristically high and food availability is limited compared to low-shore habitats. In the current study, we predicted that this scavenging behavior is induced to mitigate energy losses related to heat-shock responses-that cellulase and amylase will display hyperactivity for limited recourses in the face of aerial heating. In the laboratory, we acclimated mussels to three complex diets that differed in starch and cellulose composition, followed by two acute heat shocks (+8°C) in the laboratory. Results showed no hyperactivity of amylase and cellulase in heated mussels. These results differ from previous studies that showed lowered amylase activity following heat acclimation. This difference in amylase activity across heat-stress exposure time is important when analyzing mussel bed disturbances following heat waves that compromise energy balance or cause death within adult populations.
贻贝 Mytilus californianus 是一种生态系统工程师，它沿着东北太平洋海岸形成床层。作为固着生物，它们通过阀门运动、进食和消化功能来调节能量平衡。最近的一项研究观察到，在岸边高处的贻贝中，纤维素酶的活性高于预期，而岸边高处的温度通常较高，与低岸栖息地相比，食物供应有限。在当前的研究中，我们预测这种觅食行为是为了减轻与热休克反应相关的能量损失而诱导的-在面临空气加热时，纤维素酶和淀粉酶将在资源有限的情况下表现出过度活跃。在实验室中，我们使贻贝适应三种在淀粉和纤维素组成上有所不同的复杂饮食，然后在实验室中进行两次急性热冲击（+8°C）。结果表明，加热后的贻贝中淀粉酶和纤维素酶没有过度活跃。这些结果与先前的研究不同，先前的研究表明，在热驯化后，淀粉酶活性降低。在分析热浪对成年种群造成能量失衡或导致死亡后贻贝床层干扰时，这种跨热应激暴露时间的淀粉酶活性差异很重要。
