S-metolachlor promotes oxidative stress in green microalga Parachlorella kessleri - A potential environmental and health risk for higher organisms

Maronić, Dubravka Špoljarić; Čamagajevac, Ivna Štolfa; Horvatić, Janja; Pfeiffer, Tanja Žuna; Stević, Filip; Žarković, Neven; Waeg, Georg; Jaganjac, Morana

doi:10.1016/j.scitotenv.2018.04.433

Cited by 22 publications

(3 citation statements)

References 63 publications

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“…The reduction of chlorophyll content in algae exposed to MET can be a consequence of pigment synthesis inhibition or degradation. A decrease in Chl a and Chl b concentration was also observed in the microalgae C. pyrenoidosa (Liu and Xiong, 2009), Parachlorella kessleri (Maronic et al, 2018) and S. obliquus (Liu et al, 2017) when exposed to MET.…”

Section: Discussionmentioning

confidence: 74%

“…Some studies with green alga genera revealed distinct sensitivity of the organisms to MET. Thus, 72h-EC 50 values of 81−1090 μg L −1 for Chlorella (Liu and Xiong, 2009;Maronic et al, 2018), 44.3-115 μg L −1 for Pseudokirchneriella (Machado and Soares, 2019a;Pérez et al, 2011;Sbrilli et al, 2005;Souissi et al, 2013) and 57,100 μg L −1 for Scenedesmus were described (US-EPA, 2012b). This different sensitivity of microalgae to MET can be the consequence of different cell macromolecular composition (namely, lipids type and content and cell wall composition), different intracellular targets of MET or differences in the activation of defence mechanisms.…”

Section: Introductionmentioning

confidence: 99%

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Reproductive cycle progression arrest and modification of cell morphology (shape and biovolume) in the alga Pseudokirchneriella subcapitata exposed to metolachlor

Machado

Soares

2020

Aquatic Toxicology

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Metolachlor (MET) is an herbicide widely used and frequently found (at μg L −1) in aquatic systems. This work aimed to study the modes of action of MET on the green microalga Pseudokirchneriella subcapitata. Algae exposed to 115 or 235 μg L −1 MET, for 48 or 72 h, presented a reduction of metabolic activity, chlorophyll a and b content and photosynthetic efficiency. The exposure to 115 or 235 μg L −1 MET also induced growth yield reduction, mean cell biovolume increase and alteration of the typical algae shape (cells lunate or helically twisted) to "French croissant"-type; at these MET concentrations, algal population was mainly composed by multinucleated cells (≥ 4 nuclei), which suggest that MET impairs the normal progression of the reproductive cycle but did not hinder nuclear division. The accumulation of multinucleated cells seems to be the consequence of the incapacity of the parent cell to release the autospores. In conclusion, MET disrupts the physiology of P. subcapitata cells; the disturbance of the progression of the reproductive cycle should be in the origin of growth slowdown (or even its arrest), increase of mean cell biovolume and modification of algal shape. This work contributed to elucidate, in a systematically and integrated way, the toxic mechanism of MET on the non-target organism, the alga P. subcapitata.

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Section: Discussionmentioning

confidence: 74%

Section: Introductionmentioning

confidence: 99%

Reproductive cycle progression arrest and modification of cell morphology (shape and biovolume) in the alga Pseudokirchneriella subcapitata exposed to metolachlor

Machado

Soares

2020

Aquatic Toxicology

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“…The authors also found that the active ingredient reduced cell size, provoked rupture of the cell membrane e other alterations like the increase in the amount of starch grains and lipid droplets. Maronić et al [29] also observed similar results, mainly reduction in cell division, when testing the herbicide using the algae Parachlorella kessleri as model. These data correlate to what was found on the present study, where the herbicide provoked a reduction in mitotic index and induced the formation of alteration in the cell cycle.…”

Section: Discussionmentioning

confidence: 59%

Efects of a S-Metolachlor Based Herbicide on Two Plant Models: Zea Mays L. And <i>Lactuca Sativa L.</i>

Silva¹,

Palmieri²,

Andrade-Vieira³

2022

Preprint

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Brazil is the number-one country in pesticide consumption, and corn is the second most cultivated crop in the country. Chemical control of weeds associated with corn cultivation is performed by application of herbicides with pre- and postemergence action, such as S-metolachlor. Currently, the toxicity of herbicides is a task of great concern. In this regard, the present study aimed to evaluate the effects of an S-metolachlor-based herbicide through bioassays with the plant model Lactuca sativa L. (lettuce) and Zea mays L. (maize). The herbicidal test solutions containing 7.5, 15, 30, 60, 120, 240, 360, 480, 600, and 720 mg L-1 of the active ingredient S-metolachlor were prepared from commercial products. Distilled water was used as a negative control, and aluminum was used as a positive control. Macroscopic analyses (germination and growth) were performed for the two species, and microscopic analyses (chromosomal and nuclear changes) were performed for L. sativa. Negative interference of the S-metolachlor-based herbicide on lettuce was observed for all macroscopic and microscopic parameters tested. In maize, there was no significant interference in germination; however, the herbicide interferes negatively in seedling development. In brief, the herbicide based on S-metolachlor has phytotoxic potential, just as discussed.

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Comparative Toxicity of Herbicide Active Ingredients, Safener Additives, and Commercial Formulations to the Nontarget Alga Raphidocelis Subcapitata

Lanasa

Niedzwiecki

Reber

et al. 2022

Enviro Toxic and Chemistry

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Chloroacetanilide herbicides are used worldwide to control weeds that affect crops such as corn, soybeans, and cotton. These herbicides are frequently paired with a "safener," which prevents herbicidal damage to the crop without diminishing weed control. Formulated herbicide products that include safeners and other ingredients are infrequently assessed for toxicity. Our goal was to understand the potential toxicity of safeners and herbicide + safener formulations relative to the toxicity of associated active ingredients. We quantified the concentration of safeners in commercially available formulations and tested effects on nontarget algae, Raphidocelis subcapitata, when exposed to individual herbicide active ingredients, safeners, and commercial formulations. The median effective concentrations (EC50s) causing 50% reduction in population growth for the herbicide active ingredients S-metolachlor and acetochlor were 0.046 and 0.003 ppm, respectively. The safeners benoxacor, AD-67, furilazole, and dichlormid were all substantially less toxic than the herbicides and were not toxic at environmentally relevant concentrations. The commercial formulations Dual II Magnum ® , Me-Too-Lachlor II ® , Harness ® , and Surpass EC ® all resulted in EC50 values that fell within the 95% confidence interval of the associated active ingredient herbicide. Interestingly, a significant increase in cell size was observed when algae were exposed to all the formulations, herbicides (acetochlor and S-metolachlor), and safener (dichlormid). The safener furilazole caused a significant decrease in cell size, whereas benoxacor and AD-67 had no observed effect on algae cell size. Significant algae cell size effects all occurred at or above the EC50 concentrations for each chemical, suggesting that other morphological effects may be occurring. Importantly, safeners in commercial formulations appeared not to impact toxicity to R. subcapitata compared with the active ingredient alone.

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S-metolachlor promotes oxidative stress in green microalga Parachlorella kessleri - A potential environmental and health risk for higher organisms

Cited by 22 publications

References 63 publications

Reproductive cycle progression arrest and modification of cell morphology (shape and biovolume) in the alga Pseudokirchneriella subcapitata exposed to metolachlor

Reproductive cycle progression arrest and modification of cell morphology (shape and biovolume) in the alga Pseudokirchneriella subcapitata exposed to metolachlor

Efects of a S-Metolachlor Based Herbicide on Two Plant Models: Zea Mays L. And <i>Lactuca Sativa L.</i>

Comparative Toxicity of Herbicide Active Ingredients, Safener Additives, and Commercial Formulations to the Nontarget Alga Raphidocelis Subcapitata

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