Ammonia is one of the major pollutants in the aquatic ecosystem. Hyriopsis cumingii has great potential for the restoration of eutrophic water. However, there is no study investigating the effect of ammonia exposure in H. cumingii. The median lethal concentration (96 h LC₅₀) of unionized ammonium was 12.86 mg/L in H. cumingii. In the study, H. cumingii were exposed to 6.43 mg L⁻¹ unionized ammonium (1/2 96 h LC₅₀) for 0, 6, 12, 24, 48, 72, and 96 h. High environment ammonia induced antioxidant response to protect the body from oxidative damage. After exposure to ammonia, there was a same trend of induction followed by inhibition of the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx), and glutathione-S-transferases (GST) in the hepatopancreas and gills of H. cumingii. However, the antioxidant response could not completely counteract the oxidation effect during the exposure period, resulting in lipid peroxidation (LPO) and tissue injury in the hepatopancreas and gills of H. cumingii eventually. Moreover, this study indicated that glutamine synthetase (GS), glutamate dehydrogenase (GDH), alanine aminotransaminase (ALT), and aspartate aminotransaminase (AST) in the hepatopancreas and gills may play an important role in ammonia detoxification of H. cumingii. Our results will be helpful to understand the mechanism of aquatic toxicology induced by ammonia in shellfish.

In the present study, the accumulation and degradation of testosterone by Chlorella vulgaris were studied. The results showed that C. vulgaris has a significant ability to eliminate testosterone by bioaccumulation and biodegradation, and during the 96 h experimental period, the data demonstrated that the accumulation of testosterone followed a sigmoidal accumulation pattern. At the end of the experiment, the bioconcentration percentages of testosterone by C. vulgaris in the high-concentration group and the low-concentration group were 11.49 ± 2.78% and 40.10 ± 1.98%, respectively, and the biodegradation percentages of testosterone were 69.64 ± 4.33% and 42.48 ± 1.92%, respectively. The rate of biodegradation of testosterone by C. vulgaris mainly depended on the relative initial concentration of testosterone. When the relative initial concentration of testosterone increases, the degradation may gradually change from zero-order kinetics to second-order kinetics.

Hyriopsis cumingii plays an important role in aquatic ecosystems and fishery economy due to its potential value for water purification and edibleness. The present study was undertaken to reveal the short- and long-term purifying effects of H. cumingii on pond water. The short-term experiment results showed that total suspended solids, particulate organic carbon, and fatty acid in water were significantly eliminated by H. cumingii, with average percentage of filtering effect respectively reaching 22.19%, 57.48%, and 21.00% in the high-density group. Analogously, H. cumingii could significantly reduce phytoplankton biomass, species number, density, and chlorophyll-a concentration, especially in the control of diatoms, green algae, and cyanobacteria. Besides, electric conductivity also was significantly reduced by H. cumingii and its variation tendency showed a typical density-dependent effect. Similar purification effects were observed in chemical oxygen demand (COD), total nitrogen, and total phosphorus. In the long-term monitoring test, H. cumingii has also shown positive effects on the water transparency and the control to phytoplankton and COD in recirculating aquaculture pond. Overall, H. cumingii showed excellent ecological function, and the mixed breeding density of shellfish in the recirculating aquaculture pond is worth further exploration.

Rice field eel (Monopterus albus), a protogynous hermaphrodite fish, is a good model for the research of sex determination and gonadal differentiation in teleosts. In this study, we cloned the full-length cDNA sequence of trh, which encoded a predicted protein with 270 amino acids. Trh mainly expressed in the brain, followed by the ovary, testis, muscle and pituitary, and had low levels in other peripheral tissues. During natural sex reversal, trh mRNA expression levels exhibited a significant increase at the late intersexual stage in the hypothalamus. In the gonad, trh mRNA expression levels showed a trend of increase followed by decrease, and only increased significantly at the middle intersexual stage. No matter static incubation or intraperitoneal (IP) injection, TRH had no significant effect on trh and thyroid-stimulating hormone βsubunit (tshβ) mRNA expression levels, and serum T3, T4 and TRH release. After static incubation of ovarian fragments by TRH, the expression of gonadal soma derived factor (gsdf) was up-regulated significantly at both the doses of 10 and 100 nM. IP injection of TRH stimulated the expression of gsdf, and inhibited the expression of ovarian aromatase gene (cyp19a1a), accompanied by the increase of serum 11-KT levels. The results indicated that TRH may play a novel role in gonadal differentiation by the regulation of gonadal differentiation-related gene expression and sex steroid hormone secretion in rice field eel.