Department of Biological Sciences, University of Manitoba, Canada.
Department of Food and Human Nutritional Sciences, University of Manitoba, Canada; Canadian Centre for Agri-Food Research in Health and Medicine, St. Boniface Hospital Research Centre, Canada.
Comp Biochem Physiol A Mol Integr Physiol. 2024 May;291:111607. doi: 10.1016/j.cbpa.2024.111607. Epub 2024 Feb 14.
Chemical cues play important roles in mediating ecological interactions. Oxylipins, oxygenated metabolites of fatty acids, are one signalling molecule type that influences the physiology and function of species, suggesting their broader significance in chemical communication within aquatic systems. Yet, our current understanding of their function is restricted taxonomically and contextually making it difficult to infer their ecological significance. Snails and leeches are ubiquitous in freshwater ecosystems worldwide, yet little is known about their oxylipin profiles and the factors that cause their profiles to change. As snails and leeches differ taxonomically and represent different trophic groups, we postulated oxylipin profile differences. For snails, we hypothesized that ontogeny (non-reproductive vs reproductive) and predation (non-infested vs leech-infested) would affect oxylipin profiles. Oxylipins were characterized from water conditioned with the snail Planorbella duryi and leech Helobdella lineata, and included three treatment types (snails, leeches, and leech-infested snails) with the snails consisting of three size classes: small (5-6 mm, non-reproductive) and medium and large (13-14 and 19-20 mm, reproductive). The two species differed in the composition of their oxylipin profiles both in diversity and amounts. Further, ontogeny and predation affected the diversity of oxylipins emitted by snails. Our experimental profiles of oxylipins show that chemical cues within freshwater systems vary depending upon the species emitting the signals, the developmental stage of the species, as well as from ecological interactions such as predation. We also identified some candidates, like 9-HETE and PGE, that could be explored more directly for their physiological and ecological roles in freshwater systems.
化学线索在调节生态相互作用中起着重要作用。氧化脂类是脂肪酸的含氧代谢物，是影响物种生理和功能的一种信号分子类型，这表明它们在水生系统中的化学通讯中具有更广泛的意义。然而，我们目前对其功能的理解受到分类和背景的限制，使得难以推断它们在生态中的重要性。蜗牛和蛭类在全球淡水生态系统中无处不在，但对它们的氧化脂类谱及其导致谱变化的因素知之甚少。由于蜗牛和蛭类在分类上不同，代表不同的营养级，我们推测氧化脂类谱存在差异。对于蜗牛，我们假设个体发生（非生殖与生殖）和捕食（未受侵扰与受蛭类侵扰）会影响氧化脂类谱。从蜗牛 Planorbella duryi 和蛭类 Helobdella lineata 条件化的水中表征了氧化脂类，包括三种处理类型（蜗牛、蛭类和受蛭类侵扰的蜗牛），蜗牛有三个大小类：小（5-6mm，非生殖）和中、大（13-14mm 和 19-20mm，生殖）。这两个物种在其氧化脂类谱的组成上存在差异，无论是在多样性还是数量上。此外，个体发生和捕食影响了蜗牛释放的氧化脂类的多样性。我们的氧化脂类实验谱表明，淡水系统中的化学线索因发出信号的物种、物种的发育阶段以及捕食等生态相互作用而有所不同。我们还确定了一些候选物，如 9-HETE 和 PGE，它们可以更直接地探索其在淡水系统中的生理和生态作用。
