Variations in life history parameters, population dynamics, and transcriptome regulation of Brachionus plicatilis exposed to triclosan.

Triclosan (TCS) poses an ecological health risk due to its lipophilic nature, long half-life, and bioconcentration. To evaluate the toxicity of TCS on aquatic organisms, the life history parameters, population dynamics, and transcriptome regulation of Brachionus plicatilis exposed to TCS were investigated. In this study, the fecundity of rotifers was promoted by 25 µg/L of TCS and inhibited by higher concentrations (100 µg/L, 200 µg/L). The reproductive period of rotifers was shortened by 46.24 % but the post-reproductive period was prolonged by 176.47 % in 200 µg/L TCS. Both population growth and life table parameters indicated that a high concentration of TCS (200 µg/L) had negative impacts on population growth. Transcriptomic analysis showed that the effects of TCS on the life history parameters and population dynamics of rotifers were determined by regulating the expression of functional genes in cilium organization and cilium assembly and involved in pathways of focal adhesion.

Changes in physiological activities are responsible for homoyessotoxin-induced toxicity in abalone Haliotis discus hannai.

Homoyessotoxin (homo-YTX) is a lipid-soluble toxin produced by toxic dinoflagellates. It is widely distributed in marine ecosystems worldwide, and it poses a threat to the survival of aquatic animals. The tissues of the abalone Haliotis discus hannai are easily damaged by homo-YTX during harmful algal blooms. In this study, H. discus hannai was exposed to homo-YTX (0, 2, 5, and 10 µg L-1) to evaluate the rates of survival (S) and death (D) and the antioxidative, metabolic, and digestive physiological responses in the gills and digestive gland of abalone. Homo-YTX decreased S and the activities of Na+/K+-adenosine triphosphatase, Ca2+/Mg2+-adenosine triphosphatase, superoxide dismutase, catalase, alkaline phosphatase, xanthine oxidase, lactate dehydrogenase, amylase, protease, and lipase. Meanwhile, D, the reactive oxygen species level, and the malondialdehyde content increased with increasing concentrations of homo-YTX. In addition, homo-YTX induced oxidative stress, enhanced the lipid peroxidation reaction, reduced the energy supply, and inhibited the metabolic and digestive physiological activities in the gills and digestive gland of abalone. Oxidative stress-mediated insufficient energy supply and physiological activity reduction caused the death of abalone.

Variations in the life-cycle parameters and population growth of rotifer Brachionus plicatilis under the stress of microplastics and 17ß-estradiol.

The toxic effects of microplastics (MPs) on biota are related to their particle size. In addition, MPs could adsorb ambient pollutants in water, which increase the threat of MPs to organisms. In this study, the effects of different particle sizes and concentrations of MPs on the life-cycle parameters and population growth of rotifer Brachionus plicatilis were investigated, and the combined effects of MPs and 17ß-estradiol (E2) on rotifers were studied. Results showed small particle size (50 nm) MPs had negative effects on the lifespan, time to first batch of eggs, fecundity, and population growth rate of rotifers, which were dose-dependent, but large (100 nm and 500 nm) MPs were not. In addition, both life-cycle parameters and the population growth of rotifers were not affected by E2. However, the combination effects of different particle sizes of MPs and E2 on the lifespan, reproductive period, offspring per female, and population growth of rotifers were significant. Therefore, rotifers were more vulnerable to smaller particle MPs, and the coexistence of MPs and other environmental pollutants posed a serious threat to rotifers.