Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Bunkyo 1-14, Nagasaki 852-8521, Japan.
Graduate School of Fisheries and Environmental Sciences, Nagasaki University, Bunkyo 1-14, Nagasaki 852-8521, Japan.
Aquat Toxicol. 2022 May;246:106135. doi: 10.1016/j.aquatox.2022.106135. Epub 2022 Mar 9.
Iron (Fe), a trace metal in coastal waters has increased significantly due to anthropogenic activities, however, few studies have examined its toxicity to marine organism reproduction and associated mechanisms. We employed two marine rotifers, the temperate Brachionus plicatilis, and tropical B. rotundiformis to investigate the toxicity of iron (FeSO•7HO) and its deleterious effects on reproductive features in females (sexual fecundity, abnormal resting eggs, and swimming speed) and males (lifespan, swimming speed, and spermatozoa quality) under lethal and sub-lethal exposure. The 24 h median lethal concentration (LC) of iron was determined as 0.9 and 1.7 μg/mL per ng of dry weight for B. plicatilis and B. rotundiformis, respectively. During sub-lethal iron (20-75 μg/mL) exposure, higher iron (≥ 20 μg/mL for B. plicatilis and ≥ 45 μg/mL for B. rotundiformis) induced rotifer sexual toxicity especially in normal resting egg development and production. These were supported by the data of male shorter lifespan, poor sperm vitality, and rotifer behavioral changes as the iron concentration increased. Iron effects on swimming behavior, slower males and faster females, should reduce male/female encounter rates associated with inactive fertilized egg (resting egg) production. Two rotifer species exhibited different iron-response patterns in genetic and enzymatic activities including iron homeostasis-maintaining related Fe-S protein, and oxidative/antioxidant related lipid peroxidation product (MDA), superoxidase dismutase/SOD, catalase/CAT, and cytochrome P450 under acute iron exposure. Antioxidant activities were vulnerable in B. plicatilis but kept activities in B. rotundiformis, which may attribute to their temperate and tropical habitat adaptations.
铁（Fe）是沿海水中的一种痕量金属，由于人为活动而显著增加，但是，很少有研究检查其对海洋生物繁殖的毒性及其相关机制。我们采用两种海洋轮虫，温带褶皱臂尾轮虫和热带龟甲轮虫，研究铁（FeSO•7HO）的毒性及其对雌性（有性生殖力，异常休眠卵和游泳速度）和雄性（寿命，游泳速度和精子质量）生殖特征的有害影响在致死和亚致死暴露下。铁的 24 小时中值致死浓度（LC）分别确定为褶皱臂尾轮虫和龟甲轮虫的 0.9 和 1.7μg/mL 每 ng 干重。在亚致死铁（20-75μg/mL）暴露下，较高的铁（褶皱臂尾轮虫≥20μg/mL，龟甲轮虫≥45μg/mL）诱导轮虫的性毒性，特别是在正常休眠卵的发育和产生中。这些数据支持雄性寿命缩短，精子活力差和轮虫行为变化的数据，因为铁浓度增加。铁对游泳行为的影响，即较慢的雄性和较快的雌性，应该降低与不活跃受精卵（休眠卵）产生相关的雌雄相遇率。两种轮虫物种在遗传和酶活性方面表现出不同的铁反应模式，包括铁稳态维持相关的 Fe-S 蛋白和氧化/抗氧化相关的脂质过氧化产物（MDA），超氧化物歧化酶/SOD，过氧化氢酶/CAT 和细胞色素 P450 在急性铁暴露下。抗氧化活性在褶皱臂尾轮虫中易受影响，但在龟甲轮虫中保持活性，这可能归因于它们的温带和热带栖息地适应。
