Fig. 1

Impacts of heat stress on cardiac performance, morphology and metabolism of scallop hearts. A Heart rates (left) and representative cardiograms (right) of bay scallops under heat stress. B Scanning and Transmission electron microscopy (SEM and TEM) analysis. The characters F, H, S in SEM (I-III) stand for fissure, hole, and shrinking, respectively. The characters Z, MyF, and SpR in TEM (I-III) represent the cardiac structure Z-lines, Myofiber, and Sarcoplasmic reticulum, respectively. C In vivo contents of Norepinephrine (NE), Gamma-aminobutyric acid (GABA), acetylcholine (ACh), and activities of Acetylcholinesterase (AChE) in scallop hearts after exposure to heat stress (n = 4, mean ± SD). (D) The enzyme activities of PHD, LDH and PK, and ROS content of scallop hearts (n = 4, mean ± SD). The error bars represent SDs. The statistical significance was determined by a two-sided t-test and the P-values were shown above the plot