Laboratory of Aquatic Environmental Research, Centro de Estudios Avanzados, Universidad de Playa Ancha, Viña del Mar, Chile; Doctorado Interdisciplinario en Ciencias Ambientales, Facultad de Ciencias Naturales y Exactas, Universidad de Playa Ancha, Valparaíso, Chile; Doctorado en Ciencias del Mar y Biología Aplicada, Departamento de Ciencias del Mar y Biología Aplicada, Universidad de Alicante, Alicante, Spain; ENVIRONMENTAL HUB UPLA, Universidad de Playa Ancha, Valparaíso, Chile.
Laboratory of Aquatic Environmental Research, Centro de Estudios Avanzados, Universidad de Playa Ancha, Viña del Mar, Chile; ENVIRONMENTAL HUB UPLA, Universidad de Playa Ancha, Valparaíso, Chile.
Aquat Toxicol. 2020 Aug;225:105552. doi: 10.1016/j.aquatox.2020.105552. Epub 2020 Jun 25.
There is scarce investigation addressing interpopulation tolerance responses to address the influence of a history of chronic stress exposure, as that occurring in polluted environments, in photoautotrophs. We evaluated ecophysiological (photosynthetic activity) and metabolic (oxidative stress and damage) responses of two populations of green macroalga Ulva compressa from polluted (Ventanas) and non-polluted (Cachagua) localions of central Chile, and exposed to controlled hypersalinity conditions of 32 (control), 42, 62 and 82 psu (practical salinity units) for 6 h, 48 h and 6 d. Both primary production (ETR) and photosynthetic efficiency (α) were generally higher in the population from Cachagua compared to Ventanas at all times and salinities. Moreover, at most experimental times and salinities the population from Ventanas had greater levels of HO and lipid peroxidation that individuals from Cachagua. Total ascorbate was higher in the population of Cachagua than Ventanas at 42 and 82 psu after 6 and 48 h, respectively, while at 6 d concentrations were similar between both populations at all salinities. Total glutathione was greater in both populations after 6 h at all salinities, but at 48 h its concentrations were higher only in the population from Cachagua, a trend that was maintained at 6 d under 82 psu only. Reduced and oxidized ascorbate (ASC and DHA, respectively) and glutathione (GSH and GSSG, respectively) demonstrated similar patterns between U. compressa populations, with an increase oxidation with greater salinities but efficient recycling to maintain sufficient batch of ASC and GSH. When assessing the expression of antioxidant enzymes catalase (CAT), superoxide dismutase (SOD) and dehydroascorbate reductase (DHAR), while the population of Ventanas displayed a general trend of upregulation with increasing salinities along the experiments, U. compressa from Cachagua revealed patterns of downregulation. Results demonstrated that although both populations were still viable after the applied hypersalinities during all experimental times, biological performance was usually more affected in the population from the Ventanas than Cachagua, likely due to a depressed baseline metabolism after a long history of exposition to environmental pollution.
针对种群间的耐受性响应进行的研究很少，无法确定在受到污染的环境中（如受到污染的环境），慢性应激暴露史对光自养生物的影响。我们评估了来自智利中部受污染（文塔纳斯）和未受污染（卡查瓜）地区的两种绿藻 U. compressa 的生态生理学（光合作用活性）和代谢（氧化应激和损伤）响应，将其暴露于 32（对照）、42、62 和 82 psu（实用盐度单位）的受控高盐条件下 6 小时、48 小时和 6 天。在所有时间和盐度下，来自卡查瓜的种群的初级生产力（ETR）和光合效率（α）通常都高于文塔纳斯的种群。此外，在大多数实验时间和盐度下，文塔纳斯种群的 HO 和脂质过氧化水平均高于卡查瓜种群。在 42 和 82 psu 下，经过 6 和 48 小时后，卡查瓜种群的总抗坏血酸高于文塔纳斯种群，而在 6 天时，两个种群在所有盐度下的浓度相似。在所有盐度下，6 小时后两个种群的总谷胱甘肽浓度均较高，但在 48 小时时，仅在卡查瓜种群中的浓度较高，这种趋势仅在 82 psu 下持续到 6 天。还原型和氧化型抗坏血酸（ASC 和 DHA）和谷胱甘肽（GSH 和 GSSG）在 U. compressa 种群之间表现出相似的模式，随着盐度的增加，氧化作用增加，但有效的再循环可维持足够的 ASC 和 GSH 批次。在评估抗氧化酶过氧化氢酶（CAT）、超氧化物歧化酶（SOD）和脱氢抗坏血酸还原酶（DHAR）的表达时，文塔纳斯种群的表达一般随着实验过程中盐度的升高而上调，而卡查瓜种群的 U. compressa 则表现出下调的模式。结果表明，尽管在所有实验时间内应用高盐度后两个种群仍然存活，但在文塔纳斯种群中的生物表现通常比卡查瓜种群更受影响，这可能是由于长期暴露于环境污染后基础代谢受到抑制。
