Intertidal mussels regularly experience seasonal fluctuations in food availability and heat stress over the course of a tidal cycle, yet little is known about the biochemical mechanisms linking food ration and thermal tolerance, despite evidence that food enhances stress tolerance at the organismal level. We hypothesized that sirtuins (food-dependent protein regulators of cellular homeostasis), which may regulate the cellular stress response of mytilids during heat stress, also affect organismal performance during recovery from heat stress. As part of a broader study, we investigated the effects of acclimation food ration, acclimation emersion (air) temperature, and sirtuin inhibitors on the feeding behavior of the California mussel, Mytilus californianus, during recovery from acute aerial heat shock. Mussels were acclimated for 3 wk. to either a low (0.25% algae·g mussel dry wt⁻¹) or high (1.5% algae·g mussel dry wt⁻¹) algal ration and low (20 °C) or high (30 °C) emersion temperatures, in tidal simulator tanks capable of maintaining standard circadian and circatidal rhythms. Following acclimation, mussels were exposed to two sirtuin inhibitors (nicotinamide and suramin) or no inhibitors for one high tide cycle. During the subsequent low tide cycle, all mussels were exposed to an acute aerial heat shock (33 °C) and then allowed to recover in their respective acclimation conditions. Every 12 h during the 48 h before sirtuin inhibition and 48 h following acute heat shock (in the corresponding high tide periods), we recorded clearance rates and valve gape activity. Mussels acclimated to a low food ration significantly reduced clearance rates with heat shock and sirtuin inhibition, but not with heat shock alone, relative to pre-treatment values regardless of emersion temperature. Mussels acclimated to a low food ration and high emersion temperature showed significant reductions in valve gape activity following an acute heat shock following sirtuin inhibition, but not in any of the other acclimation groups. Unexpectedly, heat shock alone reduced clearance rates of mussels acclimated to high food and high emersion temperatures only, without any additional effect by heat shock and sirtuin inhibition. Together, these findings suggest an important role for sirtuins at the organismal level during recovery from heat shock following acclimation to a low food ration.

潮间贻贝经常在潮汐周期中经历食物供应和热应激的季节性波动，尽管有关食物增强了机体水平的压力耐受性的证据，但对食物定量和热耐受性之间关系的生化机制知之甚少。我们假设，sirtuins（细胞稳态的食物依赖性蛋白调节剂）可能调节热应激过程中Mytilids的细胞应激反应，也会影响从热应激恢复过程中的机体性能。作为更广泛研究的一部分，我们调查了适应食物的日粮，适应温度（空气）温度和瑟土因抑制剂对加利福尼亚贻贝，Mytilus californianus，从急性空气热休克中恢复。贻贝适应了3周。达到低（0.25％藻类·克贻贝干wt ^-1）或高（1.5％藻类·克贻贝干wt ^-1））在能保持标准昼夜节律和昼夜节律的潮汐模拟器水箱中的藻类定量和低温（20°C）或高温（30°C）。适应后，贻贝暴露于两种sirtuin抑制剂（烟酰胺和苏拉明）或无抑制剂，持续一个高潮周期。在随后的低潮周期中，所有贻贝都受到剧烈的空中热冲击（33°C），然后在各自的适应条件下恢复。在抑制瑟土因前48小时和急性热休克后48小时（在相应的高潮期）每隔12小时，我们记录一次清除率和气门间隙活动。适应低食物摄入量的贻贝会因热激和抑制瑟土因而显着降低清除率，但不能仅因热激而降低，相对于预处理值的大小，与温度无关。适应低食物定量和高萌发温度的贻贝在抑制瑟土因后发生急性热休克后，气门间隙活性显着降低，但在其他适应环境中均没有。出乎意料的是，仅热激会降低仅适应高食物和高萌芽温度的贻贝的清除率，而不会因热激和抑制瑟土因而产生任何其他影响。总之，这些发现表明，在适应于低食物定量的热休克恢复过程中，sirtuins在机体水平上具有重要作用。但不在其他任何适应组中。出乎意料的是，仅热激会降低仅适应高食物和高萌芽温度的贻贝的清除率，而不会因热激和抑制瑟土因而产生任何其他影响。总之，这些发现表明，在适应于低食物定量的热休克恢复过程中，sirtuins在机体水平上具有重要作用。但不在其他任何适应组中。出乎意料的是，仅热激会降低仅适应高食物和高萌芽温度的贻贝的清除率，而不会因热激和抑制瑟土因而产生任何其他影响。总之，这些发现表明，在适应于低食物定量的热休克恢复过程中，sirtuins在机体水平上具有重要作用。