da Silva Ribeiro Cristiéle, Schreiner Matthias, Iannini Carlos Arturo Navas, Dal'Olio Gomes Aline, Tolussi Carlos Eduardo, Moreira Renata Guimarães
Departamento de Fisiologia, Instituto de Biociências, Universidade de São Paulo/São Paulo, 05508-090, Brazil.
Institute of Food Science, Boku University of Natural Resources and Life Sciences, Vienna 1180, Austria.
Comp Biochem Physiol B Biochem Mol Biol. 2021 Oct-Dec;256:110625. doi: 10.1016/j.cbpb.2021.110625. Epub 2021 May 23.
Structural modifications in the gill membranes maintain homeostasis under the influence of temperature changes. We hypothesized that thermal acclimation would result in significant modification of phospholipid fatty acids, with modulation of sodium pump activity during acute (24 and 48 h) and chronic (15 days) thermal shifts in the neotropical reophilic catfish Steindachneridion parahybae. Indeed, the time-course experiment showed acute and chronic changes in gill membrane at the lowest temperatures, notably linked to maintenance of membrane fluidity: significant preferential changes in phosphatidylethanolamine, with decrease of saturated fatty acids and increase of C18:1 in all groups kept below 30 °C in chronic trial, increase in polyunsaturated fatty acids n6 and C18:1 at 17 and 12 °C compared to 24 °C, as soon as the temperature was changed (initial time). Additionally, the activity of the sodium pump increased at 12 °C, but without apparent connection with the altered lipid environment. The animals maintained at the lowest temperature showed a higher mortality, possibly because of the approach to the minimum critical temperature for this species, and unexpected results of changes in the fatty acid profile, such as decreased docosahexaenoic acid in phosphatidylethanolamine and increased saturated fatty acids in phosphatidylcholine. This set of mechanisms highlights rheostatic adjustments in this species in the face of temperature changes.
鳃膜的结构修饰在温度变化的影响下维持体内平衡。我们假设，在新热带喜温鲶鱼Steindachneridion parahybae的急性（24小时和48小时）和慢性（15天）热转移过程中，热适应会导致磷脂脂肪酸的显著修饰，并调节钠泵活性。事实上，时程实验表明，在最低温度下鳃膜发生了急性和慢性变化，这明显与膜流动性的维持有关：在慢性试验中，所有保持在30°C以下的组中，磷脂酰乙醇胺发生显著优先变化，饱和脂肪酸减少，C18:1增加；温度一旦改变（初始时间），在17°C和12°C时，多不饱和脂肪酸n6和C18:1相对于24°C增加。此外，钠泵活性在12°C时增加，但与改变的脂质环境没有明显联系。维持在最低温度的动物死亡率较高，这可能是因为接近该物种的最低临界温度，以及脂肪酸谱变化的意外结果，如磷脂酰乙醇胺中二十二碳六烯酸减少，磷脂酰胆碱中饱和脂肪酸增加。这一系列机制突出了该物种在面对温度变化时的恒流变调节。
