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Abstract: Recently, eutrophication has induced severe cyanobacterial blooms in the Naktong River, the second largest river of Korea. In the present study, lipid peroxidation and the antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, were evaluated in the liver of loach (Misgurnus mizolepis) that were orally exposed to a low dose of Microcystis through dietary supplementation with bloom scum. Loach received 75 mg of dry cells/kg body weight mass (equal to 10 μg microcystin-RR/kg body mass), for 28 days under controlled conditions. Antioxidant enzymatic activity and lipid peroxidation were measured after termination of exposure. The activities of antioxidant enzyme were significantly increased in the livers of toxin-exposed loach after 28 days of exposure, as compared to control fish. However, lipid peroxidation remained stable in both groups. These results suggest that antioxidant enzymes were able to eliminate oxidative stress induced by low concentrations of microcystins and to prevent increased lipid peroxidation in the liver of loach. [Copyright &y& Elsevier]

The subchronic oral toxicity of microcystin in common carp (Cyprinus carpio L.) was investigated in this study. The fish (mean body weight of 322±36g, n=10) were orally exposed to Microcystis by feeding with bloom scum at a dose of 50μg microcystins/kg body weight under laboratory conditions for 28 days. Growth assay results showed that microcystin could completely inhibit the growth of carp, but failed to change the fish hepatosomatic index. Ultrastructural examination by electron microscope revealed severe damage in hepatocytes derived from the treated fish. Serum biochemical assays with commercial kits indicated that alanine aminotransferase and aspartate aminotransferase activities were significantly increased as compared to control levels, but γ-glutamyl transferase, alkaline phosphatase and lactate dehydrogenase activities remained unchanged. Protein phosphatase inhibition assay revealed that the microcystin concentrations were 261.0±108.3ng microcystin-LR equivalent/g fresh weight in hepatopancreas and 38.3±12.3ng microcystin-LR equivalent/g fresh weight in muscle. The latter is above the limit recommended by the World Health Organization for human consumption. Therefore, we recommend that a warning system be instituted for announcing the occurrence of microcystin-producing water bloom and the possible risk of human intoxication. [Copyright &y& Elsevier]

The health of the world's oceans is intrinsically linked to the global climate and the well-being of humanity, which are under severe threats from human activities. Comprehensive strategies are urgently needed to protect marine environments and reduce greenhouse gas emissions to achieve the United Nations' Sustainable Development Goals. China is the largest seaweed producer, with an impressive share of over 50 % of the production of the global seaweed cultivation. This study traces the history of seaweed cultivation and illustrates the cases of important seaweed cultivation throughout China. Their profound contributions to ecological and economic benefits, as well as pivotal roles in advancing blue carbon and driving sustainable development, are unveiled. Seaweed cultivation in China has led to a significant reduction in CO 2 emission by 35.49–72.93 Tg from 2003 to 2021, through the sequestration of recalcitrant dissolved organic carbon and the accumulation of sedimentary organic carbon, accounting for 17.43–35.72 % of the initially photosynthetically fixed carbon by seaweeds. As an innovative sustainable development model for a green and low-carbon economy, the theory of seaweed-based sustainable mariculture is proposed. Seaweed culture in China is a potential nature-based solution to tackle the marine environmental problems on a global scale. Seaweed cultivation mitigates global climate change, enhances carbon sequestration, reduces ocean acidification and hypoxia, as well as helps control eutrophication and harmful algal blooms. Therefore, it is proposed that large-scale seaweed cultivation be promoted in coastal countries for a sustainable future and that a paradigm be provided to establish the seaweed-based blue carbon economy worldwide. • China is the largest seaweed producer accounting for 58 % of the global production. • Seaweed cultivation increases carbon sequestration through proper management. • Seaweed cultivation has important economic, environmental and social benefits. • Seaweed cultivation in China provides a paradigm to establish blue carbon economy. • Seaweed cultivation is worth promoting in coastal countries for a sustainable future. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the reproductive toxicity of male mice treated with Microcystis aeruginosa cell extracts containing microcystins was examined. In contrast to the control group, male mice exposed intraperitoneally to 3.33 or 6.67μg microcystins/kg body weight for 14 days had decreased mean body weight, and the mean absolute weight of the testes and epididymides was decreased. However, the mean relative weight of the testes increased compared to the controls. In addition, histological examination of microcystin-treated mice indicated that the testes were damaged and the space between the seminiferous tubules was more pronounced compared to control mice. The quality of mature sperm in the seminiferous tubules was also decreased in treated mice compared with the control group. Further studies showed that motility and viability of the sperm from microcystin-treated mice were reduced, but no significant difference was found in the concentration and abnormality of the sperm from treated mice compared to the control. This study indicated that microcystins had numerous toxic effects on the reproductive system of male mice. [Copyright &y& Elsevier]

Abstract: Microcystins produced by freshwater cyanobacteria are potent hepatotoxins and can cause animal intoxications and human illnesses. In the present study, the effects of microcystins on the embryonic development of Kunming mice were determined using cell extracts of Microcystis aeruginosa from the Nanwan reservoir, China. Forty-eight pregnant mice were divided into four groups of 12 mice. Pregnant mice in three experimental groups were injected intraperitoneally with cell extracts at doses equivalent to 3, 6, or 12μg microcystins/kg body weight daily from gestational days 6–15, while the mice in the control group were injected on the same schedule with sterilized saline. Mice were killed on the 18th day of gestation and embryonic and fetal developmental indexes checked. The fetal mice were also examined for anomalies of external, skeletal, and internal organs. The results demonstrated a significant decrease in body weight gain of pregnant mice in the 12μg/kg dose group when compared to the control group (p<0.05). Differences in mean body weight, body length, and tail length of the fetuses were also found in these two groups (p<0.05). However, no significant difference in these characteristics was detected in the 6 or 3μg/kg dose groups when compared to the control group (p>0.05). Four fetuses in the 6μg/kg body dose group were found to have a curving tail. Additionally, petechial hemorrhage and hydropic degeneration were observed in the livers of fetuses in the 6 and 12μg/kg experimental groups. These results suggested that microcystins had both maternal and embryonic toxicity in mice. [Copyright &y& Elsevier]