作者: Yang, Xiaoxia ; Ren, Xiaomin ; Liao, Zhicheng ; Shi, Min ; He, Huan ; Huang, Bin ; Lin, Yanting ; Zhan, Juhong ; Pan, Xuejun ; Guo, Ziwei ; Lai, Chaochao

Dissolved organic matter (DOM) and iron minerals widely existing in the natural aquatic environment can mediate the migration and transformation of organic pollutants. However, the mechanism of interaction between DOM and iron minerals in the microbial degradation of pollutants deserves further investigation. In this study, the mechanism of 17 alpha-ethinylestradiol (EE2) biodegradation mediated by humic acid (HA) and three kinds of iron minerals (goethite, magnetite, and pyrite) was investigated. The results found that HA and iron minerals significantly accelerated the biodegradation process of EE2, and the highest degradation efficiency of EE2 (48%) was observed in the HA-mediated microbial system with pyrite under aerobic conditions. Furthermore, it had been demonstrated that hydroxyl radicals (HO•) was the main active substance responsible for the microbial degradation of EE2. HO• is primarily generated through the reaction between hydrogen peroxide secreted by microorganisms and Fe(II), with aerobic conditions being more conducive. The presence of iron minerals and HA could change the microbial communities in the EE2 biodegradation system. These findings provide new information for exploring the migration and transformation of pollutants by microorganisms in iron-rich environments.

2024-03-01·Science of The Total Environment

Estrogen contamination increases vulnerability of amphibians to the deadly chytrid fungus

Article

作者: Prado, Joelma ; Boeing, Guilherme Andrade Neto Schmitz ; Rebouças, Raoni ; Oliveira, Cristiane R ; Carvalho, Tamilie ; Toledo, Luís Felipe ; Abdalla, Fabio Camargo ; Costa, Monica Jones ; Ribeiro, Luisa P ; Tsukada, Elisabete ; Salla, Raquel F

Aquatic contaminants and infectious diseases are among the major drivers of global amphibian declines. However, the interaction of these factors is poorly explored and could better explain the amphibian crisis. We exposed males and females of the Brazilian Cururu Toad, Rhinella icterica, to an environmentally relevant concentration of the estrogen 17-alpha-ethinylestradiol (an emerging contaminant) and to the chytrid infection (Batrachochytrium dendrobatidis), in their combined and isolated forms, and the ecotoxicity was determined by multiple biomarkers: cutaneous, hematological, cardiac, hepatic, and gonadal analysis. Our results showed that Cururu toads had many physiological alterations in response to the chytrid infection, including the appearance of cutaneous Langerhans's cells, increased blood leukocytes, increased heart contraction force and tachycardia, increased hepatic melanomacrophage cells, which in turn led to gonadal atrophy. The estrogen, in turn, increased the susceptibility of the toads to the chytrid infection (higher Bd loads) and maximized the deleterious effects of the pathogen: reducing leukocytes, decreasing the contraction force, and causing greater tachycardia, increasing hepatic melanomacrophage cells, and leading to greater gonadal atrophy, which were more extreme in females. The exposure to estrogen also revealed important toxicodynamic pathways of this toxicant, as shown by the immunosuppression of exposed animals, and the induction of the first stages of feminization in males, which corroborates that the synthetic estrogen acts as an endocrine disruptor. Such an intricate relationship is unprecedented and reinforces the importance of studying the serious consequences that multiple environmental stressors can cause to aquatic populations.

2024-01-01·Integrative Zoology

Antifertility effects of EP‐1 (quinestrol and levonorgestrel) on Pacific rats (Rattus exulans)

Article

作者: Zhang, Zhibin ; Liu, Ming ; Tu, Feiyun ; Wang, Jichao ; Liu, Jing

AbstractPest rodents pose a serious threat to island biodiversity. Fertility control could be an alternative approach to control the impact of rodents on these islands. In this study, we examined the antifertility effects of EP‐1 baits containing quinestrol (E) and levonorgestrel (P) using a dose of 50 ppm E and P at three different ratios (E:P ratio = 1:2, 1:1, and 2:1) on Pacific rats (Rattus exulans) in the Xisha Islands, Hainan, China. Compared to the control group, all animals in EP‐1 treatment groups showed significantly decreased food intake and body weight. In treated males, there were obvious abnormalities in testis structure and a significant decrease of relative seminal vesicle weight, but no significant effect on relative uterine and ovarian weights (g kg−1 body weight), or ovarian structure in females. Adding 8% sucrose to the original 50‐ppm baits (E:P ratio = 1:1) significantly increased bait palatability for males and females. This dose induced uterine edema and abnormalities of ovarian structure in females but had no significant negative effect on the relative testis, epididymis, and seminal vesicle weights (g kg−1 body weight) or sperm density in males. In summary, 50‐ppm EP‐1 (1:1) baits have the potential to disrupt the fertility of females, and 8% sucrose addition to the EP‐1 baits (E:P ratio = 1:1) could improve bait palatability. This dose disrupted the testis structure in males. Future studies are needed to improve bait acceptance and assess the antifertility effects of EP‐1 (1:1) on Pacific rats in captive breeding trials and under field conditions.

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