Toxicity of titanium dioxide nanoparticles to Chlorella vulgaris Beyerinck (Beijerinck) 1890 (Trebouxiophyceae, Chlorophyta) under changing nitrogen conditions

Dauda, Suleiman; Chia, Mathias Ahii; Bako, Sunday

doi:10.1016/j.aquatox.2017.03.020

Cited by 42 publications

(26 citation statements)

References 44 publications

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“…Levels of LPO are measured by measuring TBARS, which are a proxy for MDA, the end product of LPO. Increased MDA levels as a result of oxidative degradation of lipids cause membrane damage, impaired cellular function, and cell lysis (Rikans and Hornbrook ; Dauda et al ). As depicted in Figure B, the MDA levels in algae exposed to aged T‐AgNPs and both fresh and aged E‐AgNPs and C‐AgNPs were significantly higher ( p < 0.05) compared with the control and positively correlate with increased ROS formation.…”

Section: Resultsmentioning

confidence: 99%

The Toxicity of Nonaged and Aged Coated Silver Nanoparticles to Freshwater Alga Raphidocelis subcapitata

Lekamge

Miranda

Trestrail

et al. 2019

Enviro Toxic and Chemistry

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The transformation of coated silver nanoparticles (AgNPs) and their impacts on aquatic organisms require further study. The present study investigated the role of aging on the transformation of differently coated AgNPs and their sublethal effects on the freshwater alga Raphidocelis subcapitata. The stability of AgNPs was evaluated over 32 d, and the results indicated that transformation of AgNPs occurred during the incubation; however, coating‐specific effects were observed. Fresh AgNPs increased reactive oxygen species (ROS) formation, whereas aged AgNPs induced excessive ROS generation compared with their fresh counterparts. Increased ROS levels caused increased lipid peroxidation (LPO) in treatment groups exposed to both fresh and aged NPs, although LPO was comparatively higher in algae exposed to aged AgNPs. The observed increase in catalase (CAT) activity of algal cells was attributed to early stress responses induced by excessive intracellular ROS generation, and CAT levels were higher in the aged NP treatment groups. In conclusion, AgNPs increased ROS levels and LPO in algae and caused the activation of antioxidant enzymes such as CAT. Overall, the results suggest that aging and coating of AgNPs have major impacts on AgNP transformation in media and their effects on algae. Environ Toxicol Chem 2019;38:2371–2382. © 2019 SETAC

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Section: Resultsmentioning

confidence: 99%

The Toxicity of Nonaged and Aged Coated Silver Nanoparticles to Freshwater Alga Raphidocelis subcapitata

Lekamge

Miranda

Trestrail

et al. 2019

Enviro Toxic and Chemistry

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“…5). NPs induce ROS production [6, 25, 54, 65, ] and the upregulation of enzyme activities during exposure could be associated with increased production of ROS in the algae [21]. Generation of ROS inhibits algal growth and photosynthesis by damaging the cell membrane, nucleus and chloroplasts [21,100]; the activity of some antioxidative enzymes are triggered in defence to protect from those negative effects [38].…”

Section: Enzyme Activitymentioning

confidence: 99%

“…NPs induce ROS production [6, 25, 54, 65, ] and the upregulation of enzyme activities during exposure could be associated with increased production of ROS in the algae [21]. Generation of ROS inhibits algal growth and photosynthesis by damaging the cell membrane, nucleus and chloroplasts [21,100]; the activity of some antioxidative enzymes are triggered in defence to protect from those negative effects [38]. CAT catalyses the dismutation of H 2 O 2 to H 2 O and O 2 while GST inactivates secondary metabolites such as lipid hydroperoxides in response to ROS [52] and is responsible for the repair of ROS oxidized macromolecules of damaged cellular components [7].…”

Section: Enzyme Activitymentioning

confidence: 99%

“…To date, the data regarding the effects of AgNPs on antioxidant activities in algae are scarce. However, increased GST and CAT activities were previously recorded after exposure to other NPs such as TiO 2 NPs [21] and CuO NPs [54]. The activation of enzymes is different for AgNPs with different coatings and the toxicity may depend on the ability of the antioxidant system to activate the antioxidant enzymes at different concentrations of AgNPs with different surface functionalization.…”

Section: Enzyme Activitymentioning

confidence: 99%

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The toxicity of coated silver nanoparticles to the alga Raphidocelis subcapitata

et al. 2020

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The use of silver nanoparticles (AgNPs) is growing exponentially, especially in consumer products due to their excellent antimicrobial properties. However, concerns are growing on their possible negative effects on environmental and human health. AgNPs from consumer products enter aquatic ecosystems where their physicochemical properties including surface functionalization are critical to their impact on aquatic organisms. The effects of AgNPs coated with three different ligands; tyrosine (T-AgNP), epigallocatechin gallate (E-AgNP) and curcumin (C-AgNP) and Ag + ions on the freshwater green alga Raphidocelis subcapitata were investigated. Stability tests of AgNPs revealed that the coating significantly affects the fate and behaviour of AgNPs. All types of AgNPs tested and ionic silver were found to be toxic to the alga and differential growth inhibition of algae were observed from differently coated AgNPs, with the 48 h EC 50 of C-AgNPs, T-AgNPs and E-AgNPs being 0.155, 0.163 and 0.243 mg L −1 , respectively, in comparison with 0.051 mg L −1 for Ag + ions. Associated Ag in the algae increased with increased concentrations of all AgNPs and Ag + ions and the toxicity positively correlated to the associated Ag content in algae. The antioxidant enzymes glutathione S-transferase and catalase were activated in algal cells by the AgNPs and Ag + ions, but a consistent difference in response was not identified with different concentrations of NPs. This study shows the effects of the surrounding environment and surface functionalization of AgNPs on algae highlighting the importance of considering them in environmental risk assessment of AgNPs.

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“…It is one of the key parameters for ecological risk assessment indicating the maximum concentration at which the ecosystem is protected. Many toxicity studies have shown that C. vulgaris is usually a preferred test organism, since it has a widespread distribution and it can be found in freshwater ecosystems naturally In addition to being reported as one of the eight most tolerant genera, studies have also shown that rapid growth, efficient organic and nutrient uptake from wastewater, reduced toxicity from wastewater (wastewater treatment), and the dominance of wastewater worldwide, including temperate climates, made Chlorella sp. as the model species …”

Section: Introductionmentioning

confidence: 99%

Assessments of Algal Toxicity and PBT Behaviour of Pesticides with No Eco‐toxicological Data: Predictive Ability of QSA/(T)R Models

Gökçe

Saçan

2019

Molecular Informatics

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This paper is dedicated to Prof. Paola Gramatica on the occasion of her retirement.Abstract: In the present study, the effect of eight pesticides with no ecotoxicological data on the growth rate of Chlorella vulgaris was measured. The selected pesticides are acetochlor, acetamiprid, boscalid diphenamid, gibberellic acid, ioxynil, diclofop and 2,4,5-T. The algal toxicity (IC 50 ) of boscalid could not be determined within its solubility limit. Acetamiprid, diphenamid and gibberellic acid revealed IC 50 values > 100 mg/L. Among the others, the order of 96-h IC 50 of pesticides was found as acetochlor > ioxynil > diclofop > 2,4,5-T. The IC 50 values were also predicted by using four Quantitative Structure-Activity/(Toxicity) Relationship (QSA/ (T)R) models selected from the literature. The predictions of the models provided by QSARINS-Chem module of QSARINS as well as those obtained in our previous studies were compared with the results of experimental algal toxicity tests that were performed in our laboratory. The QSTR model generated for the toxicity of diverse chemicals to freshwater algae was able to correctly predict the toxicity order of the pesticides tested in the present study, confirming the utility of the QSA/(T)R approach. Additionally, Persistence, Bioaccumulation and Toxicity (PBT) Index model provided via the software QSARINS was employed and boscalid and diclofop were found to be PBT chemicals based on the PBT model. The present study will be very helpful when a more holistic approach applied to understand the fate of these chemicals in the environment.

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Toxicity of titanium dioxide nanoparticles to Chlorella vulgaris Beyerinck (Beijerinck) 1890 (Trebouxiophyceae, Chlorophyta) under changing nitrogen conditions

Cited by 42 publications

References 44 publications

The Toxicity of Nonaged and Aged Coated Silver Nanoparticles to Freshwater Alga Raphidocelis subcapitata

The Toxicity of Nonaged and Aged Coated Silver Nanoparticles to Freshwater Alga Raphidocelis subcapitata

The toxicity of coated silver nanoparticles to the alga Raphidocelis subcapitata

Assessments of Algal Toxicity and PBT Behaviour of Pesticides with No Eco‐toxicological Data: Predictive Ability of QSA/(T)R Models

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