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Evaluation and comparison of the mitochondrial and developmental toxicity of three strobilurins in zebrafish embryo/larvae
2021
Yang, Lihua | Huang, Tao | Li, Ruiwen | Souders, Christopher L. | Rheingold, Spencer | Tischuk, Claire | Li, Na | Zhou, Bingsheng | Martyniuk, Christopher J.
Strobilurin fungicides have been frequently detected in aquatic environments and can induce mitochondrial toxicity to non-target aquatic organisms. However, the derived toxicity and subsequent mechanisms related to their adverse effects are not fully elucidated. In the present study, we compared the mitochondrial and developmental toxicity of azoxystrobin, pyraclostrobin, and trifloxystrobin using zebrafish embryo/larvae. The results showed that all three strobilurins inhibited mitochondrial and non-mitochondrial respiration (the potency is pyraclostrobin ≈ trifloxystrobin > azoxystrobin). Behavioral changes indicated that sublethal doses of pyraclostrobin and azoxystrobin caused hyperactivity of zebrafish larvae in dark cycles, whereas trifloxystrobin resulted in hypoactivity of zebrafish larvae. In addition, pyraclostrobin exposure impaired the inflation of swim bladder, and caused down-regulation of annexin A5 (anxa5) mRNA levels, and up-regulated transcript levels of pre-B-cell leukemia homeobox 1a (pbx1a); conversely, azoxystrobin and trifloxystrobin did not cause detectable effects with swim bladder inflation. Molecular docking results indicated that azoxystrobin had higher interacting potency with iodotyrosine deiodinase (IYD), prolactin receptor (PRLR), antagonistic conformation of thyroid hormone receptor β (TRβ) and glucocorticoid receptor (GR) compared to pyraclostrobin and trifloxystrobin; pyraclostrobin and azoxystrobin were more likely to interact with the antagonistic conformation of TRβ and GR, respectively. These results may partially explain the different effects observed in behavior and swim bladder inflation, and also point to potential endocrine disruption induced by these strobilurins. Taken together, our study revealed that all three strobilurins alter mitochondrial bioenergetics and cause developmental toxicity. However, the toxic phenotypes and underlying mechanisms of each chemical may differ, and this requires further investigation. Pyraclostrobin showed higher mitochondrial toxicity at lethal doses and higher developmental toxicity at sublethal doses compared to the two other strobilurins tested. These results provide novel information for toxicological study as well as risk assessment of strobilurin fungicides.
Afficher plus [+] Moins [-]No radioactive contamination from the Chernobyl disaster in Hungarian white truffles (Tuber magnatum)
2019
Büntgen, Ulf | Jaggi, Maya | Egli, Simon | Heule, Martin | Peter, Martina | Zagyva, Imre | Krusic, Paul J. | Zimermann, Stephan | Bagi, Istvan
Despite being one of the most expensive gourmet foods, it remains unclear if the iconic White Truffle (Tuber magnatum Pico; hereinafter WT) accumulates radioactivity at harmful levels comparable to other fungal species. Here, we measure the active radiocaesium-137 concentration (137Cs) in ten hypogeous WT fruitbodies from southern Hungary, and the soils in which they were growing. All WTs reveal non-significant 137Cs values, thus providing an ‘all clear’ for WT hunters in the species' northernmost habitats, where corresponding soil samples occasionally exhibit slight 137Cs concentrations. Our results are particularly relevant in the light of a rapidly increasing global demand for WTs and their subsequent trading extent and price inflation, because up to 600 kg of fresh fruitbodies are harvested each year in southern Hungary. Moreover, some of Europe's forest ecosystems, in which mushroom picking is common practise, are still contaminated with 137Cs from the Chernobyl fallout more than 30 years ago, posing a serious threat to human health.
Afficher plus [+] Moins [-]Environmental impacts of dredging and other sediment disturbances on corals: A review
2012
Erftemeijer, Paul L.A. | Riegl, Bernhard | Hoeksema, Bert W. | Todd, Peter A.
A review of published literature on the sensitivity of corals to turbidity and sedimentation is presented, with an emphasis on the effects of dredging. The risks and severity of impact from dredging (and other sediment disturbances) on corals are primarily related to the intensity, duration and frequency of exposure to increased turbidity and sedimentation. The sensitivity of a coral reef to dredging impacts and its ability to recover depend on the antecedent ecological conditions of the reef, its resilience and the ambient conditions normally experienced. Effects of sediment stress have so far been investigated in 89 coral species (∼10% of all known reef-building corals). Results of these investigations have provided a generic understanding of tolerance levels, response mechanisms, adaptations and threshold levels of corals to the effects of natural and anthropogenic sediment disturbances. Coral polyps undergo stress from high suspended-sediment concentrations and the subsequent effects on light attenuation which affect their algal symbionts. Minimum light requirements of corals range from <1% to as much as 60% of surface irradiance. Reported tolerance limits of coral reef systems for chronic suspended-sediment concentrations range from <10mgL⁻¹ in pristine offshore reef areas to >100mgL⁻¹ in marginal nearshore reefs. Some individual coral species can tolerate short-term exposure (days) to suspended-sediment concentrations as high as 1000mgL⁻¹ while others show mortality after exposure (weeks) to concentrations as low as 30mgL⁻¹. The duration that corals can survive high turbidities ranges from several days (sensitive species) to at least 5–6weeks (tolerant species). Increased sedimentation can cause smothering and burial of coral polyps, shading, tissue necrosis and population explosions of bacteria in coral mucus. Fine sediments tend to have greater effects on corals than coarse sediments. Turbidity and sedimentation also reduce the recruitment, survival and settlement of coral larvae. Maximum sedimentation rates that can be tolerated by different corals range from <10mgcm⁻²d⁻¹ to >400mgcm⁻²d⁻¹. The durations that corals can survive high sedimentation rates range from <24h for sensitive species to a few weeks (>4weeks of high sedimentation or >14days complete burial) for very tolerant species. Hypotheses to explain substantial differences in sensitivity between different coral species include the growth form of coral colonies and the size of the coral polyp or calyx. The validity of these hypotheses was tested on the basis of 77 published studies on the effects of turbidity and sedimentation on 89 coral species. The results of this analysis reveal a significant relationship of coral sensitivity to turbidity and sedimentation with growth form, but not with calyx size. Some of the variation in sensitivities reported in the literature may have been caused by differences in the type and particle size of sediments applied in experiments. The ability of many corals (in varying degrees) to actively reject sediment through polyp inflation, mucus production, ciliary and tentacular action (at considerable energetic cost), as well as intraspecific morphological variation and the mobility of free-living mushroom corals, further contribute to the observed differences. Given the wide range of sensitivity levels among coral species and in baseline water quality conditions among reefs, meaningful criteria to limit the extent and turbidity of dredging plumes and their effects on corals will always require site-specific evaluations, taking into account the species assemblage present at the site and the natural variability of local background turbidity and sedimentation.
Afficher plus [+] Moins [-]Developing long- and short-run nexus between industrial growth, economic growth, and trade balance of China
2022
Shahid, Rabia | Shijie, Li | Shah, Aadil Hameed
The study examined the short- and long-run nexus between industrial growth, economic growth, oil production, inflation, and trade deficit of China, using quarterly data from 1995Q1 to 2020Q4. We used autoregressive distributed lag model (ARDL), after affirmation of long-run relationship and uni-directional causality. To examine short-run dynamics, an error correction model (ECM) was specified, and Granger causality test was conducted to find the direction of causality between variables. Empirical findings confirmed cointegration between trade deficit and industrial growth, economic growth, inflation, and oil production. Further, uni-directional causality between trade deficit and all independent variables was found, running from independent variables towards trade deficit. Results revealed that growth of industrial production index play a substantial role in determining trade balance of China. The study further confirms the effectiveness of economic growth and inflation for trade deficit, in both short run and long run. The findings are consistent with extant literature. On the policy front, a couple of suggestions including trade policies with special focus on industrial reforms, and loose monetary policies are made on the basis of derived conclusions.
Afficher plus [+] Moins [-]How does economic complexity affect ecological footprint in G-7 economies: the role of renewable and non-renewable energy consumptions and testing EKC hypothesis
2022
Khan, Salim | Yahong, Wang | Chandio, Abbas Ali
The discussion concerning whether and how economic complexity (ECI) affects ecological footprint (EFP) has gained researchers’ consideration, while there are slight empirical evidence to support the subject matter. In the support of theoretical argument, this study provides empirical evidence by investigating the impact of ECI on EFP along with the role of disaggregated energy consumptions by using a panel dataset of G-7 economies between 1996 and 2019. To this end, we applied panel techniques of Fully-Modify OLS and Dynamic-OLS models for cointegration analysis. The results obtained from Fully-Modify OLS and Dynamic-OLS models reveal that ECI deteriorates environmental quality by increasing EFP, while renewable energy reduces ecological pollution by decreasing EFP. In addition, the increasing demand for non-renewable energy and economic growth both degrades environmental quality in G-7 countries. More interestingly, the non-linear (ECI²) relationship between ECI and EFP confirms a U-shaped association (EKC hypothesis), which suggests that after achieving a certain threshold level, economic complexity mitigates environmental degradation in G-7 economies. The empirical results also suggest that other control variables such as population growth, inflation rate, foreign direct investment, and total trade intensity lead to environmental degradation by increasing ecological footprint. Based on empirical results, the following important policy implications are drawn; first, G-7 economies should speed up the level of economic complexity along with renewable energy consumption to protect environmental quality and maintain sustainable growth and development. Secondly, the governments of G-7 countries should introduce greener technologies and promote production that are environmental friendly for drastic reduction in environmental unsustainability.
Afficher plus [+] Moins [-]Do financial regulations matters for sustainable green economy: evidence from Turkey
2021
Odugbesan, Jamiu Adetola | Rjoub, Husam | Ifediora, Chuka Uzoma | Iloka, Chiemelie Benneth
The attention of scholars and policymakers on the achievement of sustainable green economy has been on increase; however, the topic has not been exhaustively investigated. This study empirically investigates the implications of financial regulations on sustainable green economy in Turkey utilizing a time series data spanning from 1996 to 2019. This study employed Perron and Lee-Strazicich unit root test in the presence of structural break point for examining the stationarity properties of the series and FMOLS, CCR, and ARDL for estimating the long and short-run effect of the financial regulations on carbon productivity. Our study demonstrates that rule of law, economic freedom, and inflation have a significant long-run relationship with carbon productivity as confirmed by FMOLS and CCR, while rule of law, regulatory quality economic freedom, and inflation were confirmed by ARDL to have long-run causal relationship with carbon productivity. In addition, our study found that control of corruption, government effectiveness, rule of law, regulatory quality economic freedom, and inflation have a short-run causal effect on carbon productivity. Finally, this study concludes that financial regulations is significant for achieving sustainable green economy in Turkey and as such should be accorded adequate attention by the policy makers.
Afficher plus [+] Moins [-]Exploring the linkage among energy intensity, carbon emission and urbanization in Pakistan: fresh evidence from ecological modernization and environment transition theories
2020
Shah, Syed Ale Raza | Naqvi, Syed Asif Ali | Anwar, Sofia
This study uses ecological modernization and environmental transition theories to estimate the interaction among energy intensity, carbon emission and urbanization for the period of 1980–2017. We have systematically examined the empirical connections among emission, urbanization, income per capita, imports, exports, energy use, trade openness and energy intensity. The Johnson co-integration and Vector Error Correction Model (VECM) causality methods are employed for the sake of analysis. Overall findings confirm the dynamic and U-shaped relationship between emission and urbanization, and carbon emission and income per capita. The empirical results of urbanization, inflation and financial development illustrate positive association with the energy intensity, whereas trade openness, labour force participation and carbon emission show a negative association with the dependent variable. Moreover, outcomes of causality analysis provide evidence of varied causality link among the variables across the models. The study provides the implications for the decision makers in Pakistan to choose new urbanization patterns that are less reliant on energy consumption.
Afficher plus [+] Moins [-]Nexus among electricity consumption, foreign direct investment and aggregate economic activity towards Nigeria’s economic performance: evidence from a trivariate causality model
2022
Ozughalu, Uche M. | Ogbuefi, Uche C.
It is evident that there is nexus among electricity consumption, foreign direct investment and aggregate economic activity. Unfortunately, the causal relationship among the three variables in Nigeria based on modern econometric methods, recent time-series data and ways that sufficiently cater for inflation and population growth has not been adequately investigated. This study, among other things, used a trivariate vector error correction model, autoregressive distributed lag bounds test for cointegration and Granger causality test to analyse the causal relationship among electricity consumption, foreign direct investment and aggregate economic activity based on time-series data from 1970 to 2018. The study found the presence of neutral causality between electricity consumption and aggregate economic activity in the short run as well as unidirectional causality from aggregate economic activity to electricity consumption in the long run. The study also found the presence of unidirectional causality from foreign direct investment to electricity consumption as well as neutral causality between foreign direct investment and aggregate economic activity in both the short run and the long run. It is therefore recommended that steps should be taken to adequately increase foreign direct investment and aggregate economic activity in ways that will guarantee an optimal increase in electricity consumption in Nigeria.
Afficher plus [+] Moins [-]The effects of energy poverty on economic growth: a panel data analysis for BRICS countries
2021
Doğanalp, Nihat | Ozsolak, Baki | Aslan, Alper
Energy consumption is an indispensable element for the purpose of achieving economic growth. Clean energy sources must be put into use to achieve a sustainable environment. The aim of this study is to investigate the relationship among growth, energy consumption, employment, education, and inflation with PVAR, FMOLS, and DOLS analysis in BRICS countries. The study that covers the 2001–2018 observation period included growth as the dependent variable in the equation. The only common result of the three coefficient estimates is that there is no significant relationship between education and growth. However, the increase in income has a decreasing effect on the level of education. The direction of causality between the two variables is from growth to education. Contrary to the PVAR estimate, according to FMOLS and DOLS, energy consumption and employment have a positive contribution towards growth. However, according to PVAR regression results, income growth has a positive effect on employment. Moreover, a unidirectional causal relation from energy consumption to growth and a bidirectional relation between growth and employment have been determined. This one-way relationship between energy consumption and GDP depicts that the growth hypothesis is valid. Furthermore, an energy poverty problem does not exist in BRICS countries. According to FMOLS, DOLS, and PVAR forecasts, the relationship between inflation and growth is complex. In accordance with PVAR estimates, the increase in growth reduces inflation, and the causality from growth to inflation also supports the PVAR results. According to the outcome of the research, energy poverty is not observed in the panel countries. It would be wise for BRICS countries to increase their energy consumption and employment levels in order to increase growth. However, considering the air pollution caused by fossil fuel consumption, it is key that they employ renewable energy sources.
Afficher plus [+] Moins [-]The trade-off between economic growth and environmental quality: does economic freedom asymmetric matter for Pakistan?
2021
Majeed, Muhammad Tariq | Yu, Zhiyuan | Maqbool, Adnan | Genie, Mesfin | Ullah, Sana | Ahmad, Waheed
This empirical study investigates the dynamic effects of economic freedom on economic growth and air quality for Pakistan over the period 1990–2019. The ARDL results suggest that economic freedom and other variables do not have any visible impact on economic growth and pollution in the short-run. However, in the long-run, economic freedom significantly mitigates air pollution whereas inflation instability increases emissions. The NARDL results show that a partial sum of positive change in economic freedom is negatively linked with economic growth in the short term but has positive effect in the long term. However, the negative change in economic freedom has negative but insignificant impact on growth confirming asymmetric effects. The results for the pollution model show that a partial sum of positive change in economic freedom has positive impact on emissions both in the short and long-runs, whereas a negative change has no significant effect in the short-run and has negative impact in the long-run. Thus, economic freedom supports economic activities that, in turn, escalate emissions in the atmosphere.
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