Feeding Activity and Xenobiotics Modulate Oxidative Status in<i>Daphnia magna</i>: Implications for Ecotoxicological Testing

Furuhagen, Sara; Liewenborg, Birgitta; Breitholtz, Magnus; Gorokhova, Elena

doi:10.1021/es5044722

Cited by 48 publications

(28 citation statements)

References 46 publications

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“…As a proxy for antioxidant capacity, we assayed oxygen radical absorbance capacity (ORAC) according to [37] with minor modifications; the measured values were normalized to the individual protein content. This biomarker represents the water-soluble fraction of antioxidants and has been applied for analysis of antioxidant production in daphnids [38]. Samples for ORAC and protein measurements were homogenized in 100 μL of PPB buffer (75 mM, pH 7.4).…”

Section: Analysis Of Oxygen Radical Absorbance Capacity and Protein Cmentioning

confidence: 99%

Disparate effects of antibiotic-induced microbiome change and enhanced fitness in Daphnia magna

et al. 2020

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It is a common view that an organism's microbiota has a profound influence on host fitness; however, supporting evidence is lacking in many organisms. We manipulated the gut microbiome of Daphnia magna by chronic exposure to different concentrations of the antibiotic Ciprofloxacin (0.01-1 mg L-1), and evaluated whether this affected the animals fitness and antioxidant capacity. In line with our expectations, antibiotic exposure altered the microbiome in a concentration-dependent manner. However, contrary to these expectations, the reduced diversity of gut bacteria was not associated with any fitness detriment. Moreover, the growth-related parameters correlated negatively with microbial diversity; and, in the daphnids exposed to the lowest Ciprofloxacin concentrations, the antioxidant capacity, growth, and fecundity were even higher than in control animals. These findings suggest that Ciprofloxacin exerts direct stimulatory effects on growth and reproduction in the host, while microbiome-mediated effects are of lesser importance. Thus, although microbiome profiling of Daphnia may be a sensitive tool to identify early effects of antibiotic exposure, disentangling direct and microbiome-mediated effects on the host fitness is not straightforward.

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Section: Analysis Of Oxygen Radical Absorbance Capacity and Protein Cmentioning

confidence: 99%

Disparate effects of antibiotic-induced microbiome change and enhanced fitness in Daphnia magna

et al. 2020

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“…As a proxy for antioxidant capacity, we assayed oxygen radical absorbance capacity (ORAC) according to (31) with minor modifications and normalized values to protein content. This biomarker represents the water-soluble fraction of antioxidants and has been applied in daphnids (32). Samples for ORAC and protein measurements were homogenized in 100 μL of PPB buffer (75 mM, pH 7.4).…”

Section: Methodsmentioning

confidence: 99%

Disparate effects of antibiotic-induced microbiome change and enhanced fitness inDaphnia magna

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Ogonowski

et al. 2019

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13It is a common view that an organism's microbiota has a profound influence on host fitness; 14 however, supporting evidence is lacking in many organisms. We manipulated the gut 15 microbiome of Daphnia magna by chronic exposure to different concentrations of the 16 antibiotic Ciprofloxacin (0.01 -1 mg L -1 ), and evaluated whether this affected the animals' 17 fitness and antioxidant capacity. In line with our expectations, antibiotic exposure altered the 18 microbiome in a concentration-dependent manner. However, contrary to these expectations, 19 the reduced diversity of gut bacteria was not associated with any fitness detriment. Moreover, 20 the growth-related parameters correlated negatively with diversity indices; and, in the 21 daphnids exposed to the lowest ciprofloxacin concentrations, the antioxidant capacity, 22 growth, and fecundity were even higher than in control animals. These findings suggest that 23 ciprofloxacin exerts direct stimulatory effects on growth and reproduction in Daphnia, while 24 microbiome-mediated effects are of lesser importance. Thus, although microbiome profiling 25 of Daphnia may be a sensitive tool to identify early effects of antibiotic exposure, 26 disentangling direct and microbiome-mediated effects on host fitness is not straightforward. 27 68 sequencing (22 , 23). Regardless of the sequencing platform, origin of specimens, and culture 69 conditions, the core microbiome appears relatively stable, mainly comprised of 70 Betaproteobacteria, Gammaproteobacteria and facultative anaerobic Bacteroidetes species. 71At the genus level, Limnohabitans has been reported as one of the most stable and dominant 72 members in Daphnia gut, and variations in its abundance have been tied to the animal 73 fecundity (22). Although some studies have addressed the dependence of Daphnia on its 74 microbiota (9) and some short-term effects on fitness following exposure to antibiotics have 75 been observed in Daphnia magna (25, 13), the relationship between microflora perturbation 76 and host fitness is still unclear, as is the involvement and modulating role of antioxidants in 77 these relationships. 78In this study, the relationship between antibiotic-mediated gut microbiome modulation and 79 host fitness were addressed experimentally using a model cladoceran Daphnia magna. We 80 monitored changes in the gut microbiome, host longevity, growth, and reproduction, as well 81 as antioxidant levels in the exposed animals following ciprofloxacin exposure. We 82 hypothesized that the diversity and abundance of the gut-associated microflora would 83 decrease with increasing concentration of antibiotics. Furthermore, we expected longer 84 exposure time and higher antibiotic concentrations to have negative effects on somatic 85 growth, reproductive output, and antioxidant capacity. These reductions we expected would 86 be due to reduced bacterial diversity in particular, and to some extent, an altered community 87 composition. These hypotheses were tested by combining (1) long-term (21 d) exposure...

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“…Fluorescence microscopy was used to identify the uptake and gut evacuation time of CNF in the guts of daphnids exposed to 200 mg L À1 grafted and fluorophore-labeled Generation 2-CNF over a period of 60 min. The day before the exposure, the daphnids were collected from our continuous culture and transferred to fresh M7 medium and fed P. subcapitata at a concentration of 9 mg C L À1 (Furuhagen et al 2014) to ensure constant filtration rates. At the start of the exposure, 40 neonates (<24 h old) were rinsed in M7 and immediately transferred to a beaker containing 200 mg L À1 fluorescent CNF suspended in M7 medium for 4.5 h. Immediately after the CNF exposure, 10 neonates were distributed across four borosilicate beakers containing M7 and P. subcapitata at a concentration of 9 mg C L À1 ; this allowed clearance of the guts for 5, 15, 20 and 60 min.…”

Section: Feeding Inhibition Test (Exp Iii)mentioning

confidence: 99%

Multi-level toxicity assessment of engineered cellulose nanofibrils inDaphnia magna

et al. 2018

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Cellulose nanofibril (CNF)-based materials are increasingly used in industrial and commercial applications. However, the impacts of CNF on aquatic life are poorly understood, and there are concerns regarding their potential toxicity. Using a combination of standard ecotoxicological tests and feeding experiments, we assessed the effects of CNF exposure (0.206-20.6 mg/L) on the feeding (food uptake and gut residence time) and life-history traits (growth and reproduction) in the cladoceran Daphnia magna. No mortality was observed in a 48 h acute exposure at 2060 mg/L. Moreover, a 21-day exposure at low food and moderate CNF levels induced a stimulatory effect on growth, likely driven by increased filtration efficiency, and, possibly, partial assimilation of the CNF by the animals. However, at low food levels and the highest CNF concentrations, growth and reproduction were negatively affected. These responses were linked to caloric restriction caused by dilution of the food source, but not an obstruction of the alimentary canal. Finally, no apparent translocation of CNF past the alimentary canal was detected. We conclude that CNF displays a low toxic potential to filter-feeding organisms and the expected environmental risks are low.

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Feeding Activity and Xenobiotics Modulate Oxidative Status inDaphnia magna: Implications for Ecotoxicological Testing

Cited by 48 publications

References 46 publications

Disparate effects of antibiotic-induced microbiome change and enhanced fitness in Daphnia magna

Disparate effects of antibiotic-induced microbiome change and enhanced fitness in Daphnia magna

Disparate effects of antibiotic-induced microbiome change and enhanced fitness inDaphnia magna

Multi-level toxicity assessment of engineered cellulose nanofibrils inDaphnia magna

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