Effects of diuron and carbofuran and their mixtures on the microalgae Raphidocelis subcapitata

Mansano, Adrislaine S.; Moreira, Raquel Aparecida; Dornfeld, Hugo Carlos; Freitas, Emanuela Cristina; Vieira, Eny María; Sarmento, Hugo; Rocha, Odete; Seleghim, Mirna Helena Regali

doi:10.1016/j.ecoenv.2017.04.024

Cited by 53 publications

(33 citation statements)

References 83 publications

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“…In particular, the EC10 for growth inhibition was more than a factor of 10 lower than predicted by the concentration addition/independent action model (Figure 6A and detailed in the Supplemental Data, Figure S25B and C). Mansano et al (2017) also reported synergistic interactions between diuron and carbofuran, whose potencies differ by more than 1000‐fold, making the mixture experiments difficult to perform. Given the relatively high uncertainty of the effect concentrations of the low‐potency nonherbicides, this does not mean that synergy can be invoked but rather reflects the difficulty of quantifying effects for nonherbicides.…”

Section: Resultsmentioning

confidence: 99%

The Combined Algae Test for the Evaluation of Mixture Toxicity in Environmental Samples

Glauch

Escher

2020

Enviro Toxic and Chemistry

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The combined algae test (CAT) is a 96-well plate-based algal toxicity assay with the green algae Raphidocelis subcapitata that combines inhibition of 24h population growth rate with inhibition of photosynthesis detected after 2h and 24h with pulse-amplitude modulated (PAM) fluorometry using a Maxi-Imaging PAM. The CAT has been in use for more than a decade but had limitations due to incompatibilities of the measurements of the two biological endpoints on the same microtiter plates. These limitations could be overcome by increasing growth rates and doubling times on black, clear-bottom 96-well plates by application of dichromatic red/blue LED illumination. Different robotic dosing approaches and additional data evaluation approaches helped to further expand the applicability domain of the assay. The CAT differentiates between non-specifically acting compounds and photosynthesis inhibitors, such as photosystem II (PSII)-herbicides. PSII-herbicides acted immediately on photosynthesis and showed growth rate inhibition at higher concentrations. If growth was a similar or more sensitive endpoint than photosynthesis inhibition, this was an indication that the tested chemical acted non-specifically or a mixture or a water sample was dominated by chemicals other than PSII-herbicides acting on algal growth. We fingerprinted the effects of 45 chemicals on photosynthesis inhibition and growth rate and related the effects of the single compounds to designed mixtures of these chemicals detected in water samples and to Running Head: Combined algae test and mixtures This article is protected by copyright. All rights reserved. Accepted Article the effects directly measured in water samples. Most of the observed effects in the water samples could be explained by known photosystem II inhibitors such as triazines and phenylurea herbicides. The improved setup of the CAT gave consistent results with the previous method but has lower cost, higher throughput and higher precision. This article includes online-only Supplemental Data.

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Section: Resultsmentioning

confidence: 99%

The Combined Algae Test for the Evaluation of Mixture Toxicity in Environmental Samples

Glauch

Escher

2020

Enviro Toxic and Chemistry

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“…Toxicity tests using sodium chloride (NaCl) as a reference substance were performed to evaluate the physiological conditions of R. subcapitata , considering a 96‐hr exposure period (Mansano et al, 2017).…”

Section: Methodsmentioning

confidence: 99%

Caffeine reduces the toxicity of albendazole and carbamazepine to the microalgae Raphidocelis subcapitata (Sphaeropleales, Chlorophyta)

et al. 2020

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Pharmaceutically active compounds (PhACs) are emerging contaminants that have been widely detected in water bodies in the last decades, with ecological effects toward aquatic biota that have not been fully elucidated. Most studies concerning their toxicity to microalgae have only considered short-term individual PhAC exposure, rather than combined exposure to several compounds for longer time periods. In this study, we investigated the effects of albendazole (ABZ) (anthelmintic) and carbamazepine (antiepileptic), alone and in combination with caffeine, on the growth and production of chlorophyll-a of the microalgae Raphidocelis subcapitata, during 16 days of exposure. ABZ alone had a more significant effect than carbamazepine alone on the growth rate and maximum cell density of the microalgae (p < .05; analysis of variance). These results were probably related to the effect of ABZ in inhibiting enzyme complexes and cell membrane proteins related to adenosine triphosphate synthesis, which is important for cell growth. The presence of caffeine lowered the toxicities of ABZ and carbamazepine to the microalgae, probably due to its antioxidant properties, positively affecting chlorophyll-a production, growth rate, and maximum cell density. Thus, caffeine had an antagonistic interaction with the studied PhACs. The results reinforce the importance of ecotoxicological assays that compare individual and combined PhAC exposure conditions. Our findings highlighted that caffeine can be a relevant factor influencing such assays, considering its widespread occurrence in impacted water bodies.

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“…A promising tool for examining the underlying causes of toxicity to microalgal growth is flow cytometry. In addition to cell density measurements, flow cytometry can be used to analyse several morphological parameters, such as relative cell size and complexity and relative fluorescence, which is related to pigment content (Marie et al, 2005;Stachowski-Haberkorn et al, 2013;Mansano et al, 2017). Using fluorescent dyes specific to particular physiological functions, several studies have shown the usefulness of flow cytometry to indicate the toxicity of certain chemicals to microalgae (Prado et al, 2009(Prado et al, , 2012Rioboo et al, 2011;Stachowski-Haberkorn et al, 2013;Seoane et al, 2014Seoane et al, , 2017Esperanza et al, 2015;Dupraz et al, 2016;González-Pleiter et al, 2017).…”

Section: A C C E P T E Dmentioning

confidence: 99%

“…In another study considering the growth of the freshwater alga Pseudokirchneriella subcapitata (now called Raphidocelis subcapitata), the pesticides metsulfuronmethyl, terbuthylazine and bentazone tested in binary combinations with the organophosphate malathion did not result in significant interactions compared with CA predictions (Munkegaard et al, 2008). Recently, Mansano et al (2017) reported synergy resulting from the mixture of diuron and carbofuran, a carbamate insecticide, on the growth of the microalga Raphidocelis subcapitata, compared with the CA model predictions.…”

Section: Interactive Effects Of Binary Pesticide Mixturesmentioning

confidence: 99%

Toxicity of binary mixtures of pesticides to the marine microalgae Tisochrysis lutea and Skeletonema marinoi: Substance interactions and physiological impacts

et al. 2019

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This study screened binary mixtures of pesticides for potential synergistic interaction effects on growth of the marine microalgae Tisochrysis lutea and Skeletonema marinoi. It also examined the single and combined effects of three of the most toxic substances on microalgal physiology.Single substances were first tested on each microalgal species to determine their respective EC 50 and concentration-response relationships. The toxicity of six and seven binary mixtures was then evaluated in microplate experiments on the growth of T. lutea and S. marinoi, respectively, using two mixture modelling approaches: isobolograms and the MIXTOX tool, based on Concentration Addition (CA) or Independent Action (IA) models. Significant cases of antagonism (for both species) and synergism (for S. marinoi) were observed for the mixtures of isoproturon and spiroxamine, and isoproturon and metazachlor, respectively.These two mixtures, together with that of isoproturon and diuron, for which additivity was observed, were further studied for their impacts on the physiology of each species. Exposures were thus made in culture flasks at three concentrations, or concentration combinations for mixtures, selected to cause 25%, 50% and 75% growth rate inhibition. The effects of the selected pesticides singly and in combination were evaluated at three perceived effect concentrations on esterase metabolic activity, relative lipid content, cytoplasmic membrane potential and reactive oxygen species (ROS) content by flow cytometry, and on photosynthetic quantum yield (ϕ' M ) by PAM-fluorescence.Isoproturon and diuron singly and in mixtures induced 20-40% decreases in ϕ' M which was in turn responsible for a significant decrease in relative lipid content for both species. Spiroxamine and metazachlor were individually responsible for an increase in relative lipid content (up to nearly 300% for Highlights ► The toxicity of binary pesticide mixtures was evaluated on two microalgal species. ► Effects of three selected mixtures were then examined on five physiological functions. ► Effects on microalgal physiology were linked to the pesticide's toxic mode of action. ► Mixed isoproturon and metazachlor had significant synergistic effects on S. marinoi. ► Observed synergy could be due to a combined effect on the photosynthetic apparatus.

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Effects of diuron and carbofuran and their mixtures on the microalgae Raphidocelis subcapitata

Cited by 53 publications

References 83 publications

The Combined Algae Test for the Evaluation of Mixture Toxicity in Environmental Samples

The Combined Algae Test for the Evaluation of Mixture Toxicity in Environmental Samples

Caffeine reduces the toxicity of albendazole and carbamazepine to the microalgae Raphidocelis subcapitata (Sphaeropleales, Chlorophyta)

Toxicity of binary mixtures of pesticides to the marine microalgae Tisochrysis lutea and Skeletonema marinoi: Substance interactions and physiological impacts

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