The effects of warming on red blood cell carbonic anhydrase activity and respiratory performance in a marine fish
The effects of warming on red blood cell carbonic anhydrase activity and respiratory performance in a marine fish
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DOI：
10.1016/j.cbpa.2021.111033
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发表时间：
2021-07-14
影响因子：
2.3
通讯作者：
Esbaugh, Andrew J.
中科院分区：
文献类型：
--
作者：
Dichiera, Angelina M.;Khursigara, Alexis J.;Esbaugh, Andrew J.
适应度的测量是预测物种对环境变化（如水温升高）的反应的有价值的工具。有氧范围（AS）是一个衡量个人的有氧过程的能力，并经常被用作健康的代理。然而，AS是复杂的，不仅在一个物种内发现的个体差异，但在相似的身体大小以及。最大代谢率（MMR）是决定AS的因素之一，受个体在组织中输送和提取氧气（O-2）的能力的限制。最近，数据表明，红细胞碳酸酐酶（RBC CA）是红鼓（Sciaenops ocellatus）中O-2输送的限速酶。我们假设温度升高以类似的方式影响MMR和RBC CA活性，并且个体的RBC CA活性驱动AS的个体差异。在力竭运动和28 ℃下的快速流量呼吸测定之前，将红鼓急性暴露于升高的温度（+6 ℃; 22 ℃至28 ℃）24 h。在温度暴露之前和有氧性能之后测量RBC CA活性。由于酶的热敏感性，急性升温使个体RBC CA活性增加了36%，而对照组（22 ℃）治疗没有显著变化。有趣的是，急性加温处理的平均MMR比对照鼓大36%。然而，我们发现在任一温度下，个体RBC CA活性与其各自的MMR和AS之间没有关系。虽然变暖同样会影响RBC CA活性和MMR，但RBC CA活性不是个体MMR的预测因子。
Measures of fitness are valuable tools to predict species' responses to environmental changes, like increased water temperature. Aerobic scope (AS) is a measure of an individual's capacity for aerobic processes, and frequently used as a proxy for fitness. However, AS is complicated by individual variation found not only within a species, but within similar body sizes as well. Maximum metabolic rate (MMR), one of the factors determining AS, is constrained by an individual's ability to deliver and extract oxygen (O-2) at the tissues. Recently, data has shown that red blood cell carbonic anhydrase (RBC CA) is rate-limiting for O-2 delivery in red drum (Sciaenops ocellatus). We hypothesized increased temperature impacts MMR and RBC CA activity in a similar manner, and that an individual's RBC CA activity drives individual variation in AS. Red drum were acutely exposed to increased temperature (+6 degrees C; 22 degrees C to 28 degrees C) for 24 h prior to exhaustive exercise and intermittent-flow respirometry at 28 degrees C. RBC CA activity was measured before temperature exposure and after aerobic performance. Due to enzymatic thermal sensitivity, acute warming increased individual RBC CA activity by 36%, while there was no significant change in the control (22 degrees C) treatment. Interestingly, average MMR of the acute warming treatment was 36% greater than that of control drum. However, we found no relationships between individual RBC CA activity and their respective MMR and AS at either temperature. While warming similarly affects RBC CA activity and MMR, RBC CA activity is not a predictor of individual MMR.