Influence of exposure scenario on the sensitivity to caffeine.

The chorion acts as a protective barrier, restricting some chemical absorption into the embryo and the surrounding fluids. In this sense, larvae may only have direct contact with some chemicals after dechorionation. This study aimed to evaluate the effects of caffeine (CAF) (0, 13, 20, 44, 67, and 100 mg.L-1) under different exposure scenarios (embryos with chorion or embryos/larvae already hatched) and rank the stage sensitivity. Thus, three scenarios were investigated: from 2 to 120 hours post fertilization (hpf) (5 days of exposure- 5dE), from 72 to 120 hpf (2dE), and from 96 to 120 hpf (1dE). Heart rate (48 hpf) and energy reserves (120 hpf) were measured in the 5dE scenario, and behavior and acetylcholinesterase (AChE) activity were evaluated at 120 hpf in all scenarios (5dE, 2dE, and 1dE). At 120 hpf, some of the fish was transferred to clean medium for a 10 days depuration period (10dPE). Behavior and AChE activity were assessed after this period. In the 5dE scenario, CAF increased heartbeat (13, 20, and 30 mg.L-1) and reduced carbohydrates (67, and 100 mg.L-1), while inhibiting AChE activity (100 mg.L-1) in the 5dE, 2dE, and 1dE scenarios. CAF reduced the total distance moved in the 5dE (67, and 100 mg.L-1), 2dE (20, 30, 44, 67, and 100 mg.L-1), and 1dE fish (67, and 100 mg.L-1) and increased erratic movements. Based on the lowest observed effect concentration (LOEC) for total distance moved (20 mg.L-1) and higher inhibition of AChE activity (100 mg.L-1) (65%), 2dE fish appear to be more sensitive to CAF. After 10dPE, a recovery in behavior was detected in all scenarios (5dE, 2dE, and 1dE). AChE activity remained inhibited in the 2dE scenario while increasing in the 1dE scenario. This study demonstrated that the presence of the chorion is an important factor for the analysis of CAF toxicity. After the loss of the chorion, organisms show greater sensitivity to CAF and can be used to evaluate the toxicity of various substances, including nanomaterials or chemicals with low capacity to cross the chorion. Therefore, the use of hatched embryos in toxicity tests is suggested, as they allow a shorter and less expensive exposure scenario that provides similar outcome as the conventional scenario.

The role of temperature on zebrafish ontogenic development and sensitivity to pharmaceuticals.

This study assessed the effects of two emerging environmental pollutants caffeine (CAF) and metformin (METF) on juvenile zebrafish, raised at 22 °C or 27 ºC, after 96 h exposure. The temperature influenced the basal behaviour of unexposed juveniles, with higher swimming activity and a greater percentage of movements at the well edges observed in fish raised at 27 °C. A significant interaction between CAF and temperature was found for behavioural endpoints, but not for AChE activity, associated with neurotoxicity effects. CAF reduced swimming distance, increased erratic swimming, and inhibited AChE activity at 22 ºC, while at 27 ºC, CAF did not affect behaviour but increased AChE. METF exposure at 22 °C decreased swimming distance and increased erratic movements, but at 27 °C no effects were detected. Overall, temperature plays a more important role in the effects induced by CAF than METF.

Effects of environmental concentrations of caffeine on adult zebrafish behaviour: a short-term exposure scenario.

Caffeine (CAF) has been considered an emerging environmental contaminant and its presence indicator of anthropogenic contamination. This study evaluated the effects of environmental concentrations of CAF (0, 0.5, 1.5, and 300 µg. L-1) on the behaviour of adult zebrafish (Danio rerio) after 7 days of exposure. The components of feeding, locomotion, boldness (new tank test), sociability (schooling test), and aggression (mirror test) were analysed. Growth rate and weight were investigated as complementary measures. CAF (0.5, 1.5, and 300 µg. L-1) reduced exploratory behaviour in zebrafish, increased feeding latency time (1.5, and 300 µg. L-1), and decreased growth rate and fish weight (300 µg. L-1). CAF also induced aggressive behaviour (0.5, 1.5, and 300 µg. L-1) and decreased appetence to the shoal (sociability) (0.5, and 1.5 µg. L-1). This study showed that low doses of CAF can induce behavioural effects in zebrafish that may have significant long-term impacts on vital ecological functions.

Multi-level governance tackling the COVID-19 pandemic in China / A governança multinível no enfrentamento da pandemia de COVID-19 pela China / Gobernanza multinivel en China para el combate de la pandemia de COVID-19

Abstract This paper investigates China's leadership over intergovernmental and private actions in tackling the COVID-19 pandemic and identifies sectors, levels, and roles played. The main argument is that successful control over the pandemic depends on effective and integrated leadership at different levels. The conceptual, theoretical, and analytical framework is given by the multi-level governance theory. Through a case study, the actions adopted in China (n = 374) were mapped from reports issued by the Chinese government, the World Health Organization, and media information. Content analysis was adopted to categorize data. Quantitative and qualitative findings show different roles of actors, as well as usefulness of the multi-level governance to provide fast and complex responses required during the pandemic. In the last section, the conclusion and recommendations for future research are addressed. The lack of studies on the application of multi-level governance in non-democratic regimes especially during a pandemic indicates the relevance and contribution of this study to the literature.

Resumo O artigo objetiva investigar a liderança pública das ações, relações privadas e intergovernamentais da China no enfrentamento da pandemia de COVID-19, identificando setores e níveis envolvidos, bem como os papéis desempenhados. O argumento central é o de que o controle bem sucedido da pandemia depende da liderança eficaz e integrada das relações intergovernamentais e privadas nos diversos níveis. O enquadramento conceitual, teórico e analítico é dado pela teoria da governança multinível. Através do método de estudo de caso, as ações de enfrentamento adotadas na China (n = 374) foram mapeadas a partir dos relatórios emitidos pelo governo chinês, pela Organização Mundial da Saúde e informações da mídia. As ações foram categorizadas através da técnica de análise de conteúdo. Resultados quantitativos e qualitativos são apresentados e mostram os papéis dos atores, bem como a relevância da governança multinível diante da rápida e complexa resposta exigida pela emergência da pandemia. Na última seção são apresentadas as conclusões e oportunidades para desenvolvimentos futuros. A relevância da pesquisa também reside na escassez de estudos sobre a aplicação da governança multinível em regimes não democráticos, especialmente durante pandemias.

Resumen El artículo investiga el liderazgo público de China en las acciones y relaciones intergubernamentales y privadas para enfrentar la pandemia de COVID-19, al identificar los sectores y niveles involucrados, así como los roles. El argumento central es que el control exitoso de la pandemia depende de un liderazgo efectivo e integrado a diferentes niveles. La teoría de gobernanza multinivel es el marco conceptual, teórico y analítico. Las acciones adoptadas en China (n = 374) se mapearon a través del método de estudio de caso, a partir de informes emitidos por el gobierno chino, la Organización Mundial de la Salud e información de los medios y, para categorizar esos datos, se adoptó la técnica de análisis de contenido. Se presentan hallazgos cuantitativos y cualitativos que muestran los roles de los actores, así como la relevancia de la gobernanza multinivel ante la respuesta rápida y compleja requerida por la emergencia pandémica. En la última sección se exponen las conclusiones y recomendaciones para futuras investigaciones. La falta de estudios sobre la aplicación de la gobernanza multinivel en regímenes no democráticos, especialmente durante una pandemia, demuestra la relevancia de este estudio y su contribución a la literatura.

Chronic effects of carbamazepine on zebrafish: Behavioral, reproductive and biochemical endpoints.

Carbamazepine (Cbz), one of the most prescribed pharmaceuticals in the world is often detected in surface waters and sediments. However, few studies addressed its chronic effects in fish. In the present study, Danio rerio adults were exposed for 63 days to Cbz (0 - control, 10 µg L-1 - concentration found in effluents, and 10,000 µg L-1 - 5% of LC50 at 72 h). Assessed endpoints were: feeding behavior, growth rate, number of eggs produced and their viability, histological alterations in female gonads, and biochemical biomarkers associated with antioxidant defenses (catalase - CAT, and glutathione S-transferase - GST activities), neurotransmission (acetylcholinesterase activity - AChE) and metabolism (lactate dehydrogenase - LDH). Cbz exposure increased the total time for food intake but did not affect D. rerio growth. Although the total number of eggs was not affected by Cbz exposure, the eggs viability was significantly impaired. Exposure to Cbz caused alterations in the female gonads follicular stages. In terms of biochemical endpoints, CAT activity in liver and gills, was sensitive to the pharmaceutical exposure presenting a decreased activity. AChE activity was induced in the head (both concentrations) and muscle (10,000 µg L-1). GST activity was increased in gills (both concentrations) but inhibited in the intestine. Concerning LDH, enzymatic activity was increased in the liver and decreased in muscle and gills. Several of the above-mentioned effects can be directly linked with effects at population level (e.g. feeding behavior) and occurred at environmental concentrations (the lowest concentration tested), thus serious concerns regarding risks posed by Cbz residues to fish populations arise with this study.