Control of Suitability of the Culture Daphnia magna Straus for Bioassays of Aquatic Environments, Taking into Account Demographic Indicators of Model Populations

Olkova, Anna

doi:10.3390/w13010047

Cited by 5 publications

(5 citation statements)

References 14 publications

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“…Although the above observations by (32) may only be transferred to other metals, it seems plausible that energy limitation due to detoxification could also be a factor in other toxicity tests. In addition, ( 36), (37) showed that the test water composition may also influence sensitivity of neonates.…”

Section: Discussionmentioning

confidence: 99%

Miniaturisation of the Daphnia magna immobilisation assay for the reliabletesting of low volume samples

Küster,

Addo,

Aulhorn

et al. 2023

Preprint

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International standard test guidelines for the ecotoxicological characterisation of various substances use organisms like algae, daphnids and fish embryos. These guidelines use relatively high volumes of water for the process of testing. However, for various samples such as extracts from environmental monitoring or leachates from microplastic aging experiments, the amount of available sample volume is limited. Using the exposure volumes as recommended in test guidelines would not allow to test a range of different concentrations or to repeat tests. Lower media volumes would allow the testing of more samples (more concentrations per sample, more test repetitions for statistical robustness) but it may also decrease the possible number of organisms tested in the same volume. Here, we aimed at reducing the test volumes in the acute daphnia assay without impacting animals’ sensitivity towards toxicants. A literature review on existing miniaturisation approaches was used as a starting point. Subsequently, assays employing conventional as well as reduced test volumes were compared for 15 selected test substances with a diverse spectrum of lipophilicity. Results showed that there are differences in EC 50 between the two approaches, but that these differences were overall only within a range of a factor of two to three. Further, by retrieving EC50 values for the genus Daphnia and 15 test substances from the US EPA database, we demonstrated that our results are well inline with the general differences in sensitivities.

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Section: Discussionmentioning

confidence: 99%

Miniaturisation of the Daphnia magna immobilisation assay for the reliabletesting of low volume samples

Küster,

Addo,

Aulhorn

et al. 2023

Preprint

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“…The dissolved oxygen had a concentration higher than 6 mg/L. For homogenization and standardization purposes, all the experiments were carried out with individuals <24 h old, born between the third and fifth brood (Olkova, 2021).…”

Section: Methodsmentioning

confidence: 99%

Toxicity of fluoroquinolones on the cladoceran Daphnia magna

Eluk

Nagel

Gagnetén

et al. 2021

Water Environment Research

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This study evaluates the acute and chronic toxicological effects of six fluoroquinolones on the mortality and growth of Daphnia magna. The NOECs calculated with the multivariate Probit regression model for the chronic study were 56 μg/L ciprofloxacin, 63 μg/L enrofloxacin, 78 μg/L levofloxacin, 85 μg/L marbofloxacin, 69 μg/L norfloxacin, and 141 μg/L ofloxacin. The risk quotients were determined using the measure environmental concentrations reported in water sources from different countries. The risks were low and moderate in water samples from rivers and lakes, although concentrations of ciprofloxacin, norfloxacin, and ofloxacin reported in some countries can cause toxicological damage to D. magna. In addition, urban wastewater and hospital wastewater samples constitute a threat to D. magna (high and moderate risks), requiring the treatment of these wastewater. Practitioner points The NOECs calculated with the multivariate Probit model for the six fluoroquinolonas are between 56 μg/L ciprofloxacin and 141 μg/L ofloxacin. The levels of ciprofloxacin, norfloxacin, and ofloxacin in urban wastewater and hospital wastewater produce moderate and high risks for D. magna. Water and river samples from some countries containing ciprofloxacin, norlfoxacin, and ofloxacin present high risks for D. magna.

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“…As for the positive control, potassium dichromate was used at concentrations ranging from 0.2 to 10 µg/mL (0.2, 0.4, 0.6, 2.0, 4.0, and 10 µg/mL, corresponding to 0.6, 1.3, 2.0, 6.8, 13.6, and 34.0 µM) based on preliminary data. The reference test with potassium dichromate [54] was performed to ensure the sensitivity of Daphnia and to meet the validity criterion outlined in the OECD (The Organisation for Economic Co-operation and Development) guideline 202. For this criterion, the LC 50 of potassium dichromate at 24 h needed to fall within the range of 0.6 to 2.1 µg/mL.…”

Section: Acute Toxicity Assessment Using Daphnia Magnamentioning

confidence: 99%

Inhibitory Effects on Staphylococcus aureus Sortase A by Aesculus sp. Extracts and Their Toxicity Evaluation

Olaru,

Nitulescu,

Codreanu

et al. 2024

Plants

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A promising strategy for combating bacterial infections involves the development of agents that disarm the virulence factors of pathogenic bacteria, thereby reducing their pathogenicity without inducing direct lethality. Sortase A, a crucial enzyme responsible for anchoring virulence factors to the cell surface of several pathogenic bacteria, has emerged as a possible target for antivirulence strategies. A series of hippocastanum species (Aesculus pavia, A. parviflora, Aesculus x carnea, and A. hippocastanum) were used to prepare ethanol- and water-based extracts for assessing their effect on Staphylococcus aureus sortase A. The extracts were characterized through HPLC analysis, and their polyphenols content was determined using the Folin–Ciocalteu method. The specific toxicity profile was evaluated in Daphnia magna using the median lethal concentration (LC50) and against the fibroblast MRHF cell line. The half maximal inhibitory concentration (IC50) values on sortase A, determined after 30 min of incubation, ranged from 82.70 to 304.31 µg/mL, with the A. pavia water extract exhibiting the highest inhibitory effect. The assessment of the A. pavia water extract on human fibroblasts revealed no significant signs of toxicity, even at a concentration of 500 µg/mL. This reduced toxicity was further validated through the Daphnia assay. These findings highlight the low toxicity and the potential of this extract as a promising source of future development of bacteria antivirulence solutions.

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Control of Suitability of the Culture Daphnia magna Straus for Bioassays of Aquatic Environments, Taking into Account Demographic Indicators of Model Populations

Cited by 5 publications

References 14 publications

Miniaturisation of the Daphnia magna immobilisation assay for the reliabletesting of low volume samples

Miniaturisation of the Daphnia magna immobilisation assay for the reliabletesting of low volume samples

Toxicity of fluoroquinolones on the cladoceran Daphnia magna

Inhibitory Effects on Staphylococcus aureus Sortase A by Aesculus sp. Extracts and Their Toxicity Evaluation

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