[Combined effects of fluoxetine and triclosan on Pseudorasbora parva.] / 氟西汀与三氯生复合暴露对麦穗鱼的毒性效应.

We examined the effects of binary mixture of two different pharmaceutical and personal care products (PPCPs) on aquatic organisms. The topmouth gudgeon Pseudorasbora parva, native to northeast China, was used to study the combined effects of fluoxetine (FLX) and triclosan (TCS) on its different organs. After acute (4 h) and chronic (42 d) treatments, the combined effects of FLX/TCS on phase I and phase II detoxification enzymes, nervous system, digestive system and antioxidant system were evaluated. The results showed that the AChE activity in the brain of P. parva was transiently inhibited, whereas the activity of EROD in the liver was continuously inhi-bited. The activity of α-Glu in the intestine was induced after acute exposure but was inhibited after chronic exposure. Meanwhile, the level of lipid peroxidation in the liver was elevated after chronic exposure. In conclusion, the mixture of fluoxetine and triclosan produced toxic effects on multiple organs of P. parva, which could be alleviated after prolonged exposure, indicating an acclimation. However, the mechanisms of this acclimation needed further study.

Dydrogesterone Causes Male Bias and Accelerates Sperm Maturation in Zebrafish ( Danio rerio).

Synthetic progestins are widely used in human and veterinary medicine. They can enter aquatic environments mainly via wastewater discharge and agricultural runoff, thus affecting fish populations in receiving waters. Here, we investigated the chronic effects of dydrogesterone (DDG) on zebrafish from 21 to 140 days post-fertilization (dpf) at 3.39, 33.1, and 329 ng L-1. The results showed that the male ratio increased with the exposure concentration, and after 120 days of exposure to 329 ng L-1, 98% of the fish were males. The DDG exposure during sex differentiation significantly increased the transcription of dmrt1 (1.83-fold) and apoptosis-related genes but suppressed the transcription of cyp19a1a (3.16-fold). Histological analysis showed that the exposure to DDG at 329 ng L-1 caused 61.5% of mature spermatocytes in males, while the exposure to DDG at 33.1 ng L-1 resulted in 14.7% of atretic follicles in females. Microarray analysis identified spermatogenesis-related gene ontology (endothelial barrier and immune response) in the testes at all concentrations. Genes from phagosome, lysosome, and sphingolipid metabolism pathways were enriched and could be responsible for sperm maturation. The findings from this study demonstrate that DDG in the aquatic environment can cause male bias and accelerate sperm maturation in zebrafish, resulting in potential high ecological risks to fish populations.

[Mechanisms of Cr (VI) toxicity to fish in aquatic environment: A review].

With increasing consumption and applications of chromium in metallurgy, electroplating, tanning process and stainless steel industry, chromium contamination has become a global environmental problem. In general, Cr(VI) has higher permeability across the cell membrane than Cr(III) and hence is considered more toxic than Cr(III). Oxidative stress could be induced following reactive oxygen species (ROS) normally produced in fish under Cr(VI) exposure due to its variable valences. Furthermore, the intermediates of Cr, e.g. Cr(V) and Cr(IV) , produced by cellular reduction processes can bind with DNA and result in mutagenic effects. These combined effects will threaten the growth, development and population structure of different fish species. In this paper, we reviewed published results on the toxic effects of Cr(VI) in fish at levels of molecules, tissues, organs and individuals. The mechanisms of toxicity and detoxification of Cr(VI) in various aspects were discussed. In addition, we also put forward perspectives on the toxicity of chromium in aquatic organisms.