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Dissolved humic substances - Part XI: direct effects on aquatic animals

机译：溶解的腐殖质-第十一部分：对水生动物的直接影响

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In contrast to current paradigms, humic substances may be taken up by aquatic organisms. Their molecular size is not too large to pass biomembranes. This has been proven with the oxidation product of caffeic acid, a humic substance surrogate with nominal 6 kDa molecular weight. In the aquatic organisms studied, water fleas, insect larvae, snails and fish, stress and detoxication reactions are induced, comparable to reactions to xenobiotica exposure. Non-specific biomarkers such as heat-shock proteins are activated, ultrastructural changes occur in the endoplasmic reticulum and detox-ication enzymes are modulated, particularly those of phase II. The latter shows a doseresponse relationship. Exposure of the common water snail Lymnea stagnalis to Suwannee River isolates obviously exhausted the detoxication enzymes, and a significant proportion of the snails died within 24 hours. Exposed to the nematode Caenorhabditis elegans, humic substances have the potential to modulate the number of offspring per individual. Non-specific detoxication biomarkers could also be found in fish. However, the net effect of humic substance exposure is positive with the r-strategist zebrafish (Danio rerio), and with the K-strategist swordtail (Xiphophorus helleri). Thismay be due to indirect effects such as deactivation of parasites and pathogenes.
机译：与当前的范例相反，腐殖质可能被水生生物吸收。它们的分子大小不太大，无法通过生物膜。咖啡酸的氧化产物已经证明了这一点，咖啡酸是一种腐殖质替代物，其标称分子量为6 kDa。在所研究的水生生物中，诱发了水蚤，昆虫幼虫，蜗牛和鱼类，引起了压力和脱毒反应，这与暴露于异种菌的反应相当。非特异性生物标记物（例如热激蛋白）被激活，在内质网中发生超微结构变化，排毒酶被调节，特别是第二阶段的排毒酶。后者显示剂量反应关系。常见的水生蜗牛Lymnea stagnalis暴露于Suwannee河分离株中时，其脱毒酶明显耗尽，并且有很大比例的蜗牛在24小时内死亡。暴露于线虫秀丽隐杆线虫的腐殖质有可能调节每个人的后代数量。在鱼类中也可以找到非特异性的脱毒生物标志物。但是，腐殖质暴露的净效应对r策略家的斑马鱼（Danio rerio）和K策略家的剑尾（Xiphophorus helleri）都是积极的。这可能是由于间接影响，例如寄生虫和病原体的失活。

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