Automated swimming activity monitor for examining temporal patterns of toxicant effects on individual Daphnia magna

Abstract

Aquatic pollutants are often biologically active at low concentrations and impact on biota in combination with other abiotic stressors. Traditional toxicity tests may not detect these effects, and there is a need for sensitive high-throughput methods for detecting sublethal effects. We have evaluated an automated infra-red (IR) light-based monitor for recording the swimming activity of Daphnia magna to establish temporal patterns of toxicant effects on an individual level. Activity was recorded for 48 h and the sensitivity of the monitor was evaluated by exposing D. magna to the reference chemicals K2 Cr2 O7 at 15, 20 and 25 °C and 2,4-dichlorophenol at 20 °C. Significant effects (P < 0.001) of toxicant concentrations, exposure time and incubation temperatures were observed. At 15 °C, the swimming activity remained unchanged for 48 h at sublethal concentrations of K2 Cr2 O7 whereas activity at 20 and 25 °C was more biphasic with decreases in activity occurring after 12-18 h. A similar biphasic pattern was observed after 2,4-dichlorophenol exposure at 20 °C. EC50 values for 2,4-dichlorophenol and K2 Cr2 O7 determined from automated recording of swimming activity showed increasing toxicity with time corresponding to decreases in EC50 of 0.03-0.07 mg l(-1) h(-1) . EC50 values determined after 48 h were comparable or lower than EC50 values based on visual inspection according to ISO 6341. The results demonstrated that the swimming activity monitor is capable of detecting sublethal behavioural effects that are toxicant and temperature dependent. The method allows EC values to be established at different time points and can serve as a high-throughput screening tool in toxicity testing. Copyright © 2015 John Wiley & Sons, Ltd.

Using a new high-throughput video-tracking platform to assess behavioural changes in Daphnia magna exposed to neuro-active drugs

“…There is an increasing number of studies that have used video tracking devices to assess changes in Daphnia swimming behaviour upon exposure to chemicals (Artells et al, 2013;Bahrndorff et al, 2016;Barrozo et al, 2015;Bownik et al, 2018;Cano et al, 2017;Cruzeiro et al, 2017;Chevalier et al, 2015;Ferrario et al, 2018;Häder and Erzinger, 2017;Hansen and Roslev, 2016;Huang et al, 2017;Huang et al, 2015;Liu et al, 2018;Madeira et al, 2018;Nielsen and Roslev, 2018;Nikitin et al, 2018;Noss et al, 2013;Parolini et al, 2018;Ren et al, 2017;Ren et al, 2015;Stanley et al, 2016;Yang et al, 2018;Zein et al, 2014;Zhang et al, 2016). However, only few of them reported behavioural effects at environmental relevant concentrations far below those causing any sublethal effects on stress markers or lifehistory traits (Nielsen and Roslev, 2018).…”

“…infrared light) and software calibration. Despite the increasing number of studies that have used automated video recording system to monitor Daphnia swimming behaviour (Bownik, 2017), few used infrared light-based monitors (Bahrndorff et al, 2016;Chevalier et al, 2014) and none combined both visible and infrared light to allow the simultaneous measurement of behavioural responses under dark and light.…”

The Novel Concept of “Behavioural Instability” and Its Potential Applications

“…The concept of behavioural instability could have several possible applications as a biomonitoring tool if we expect that changes in environmental conditions can produce changes in the behavioural traits. For example, behavioural traits have been used in toxicological studies as a sensitive indicator of stress using traits such as swimming activity, locomotor activity or flight [30][31][32][33]. Behavioural instability provides another way of analysing data compared to traditional measures such as total distance traveled, activity per hour or swimming distance.…”

Avaliação ecogenotoxicológica de corante natural extraído de micro-organismo

“…Condições ambientais desfavoráveis podem causar um declínio nos custos metabólicos de daphnídeos, analisados pela quantificação da taxa respiratória dos organismos (MICHELS et al, 2000;MARTINS et al, 2007;REN et al, 2009;BAHRNDORFF et al, 2015;HANSEN;ROSLEV, 2016;HÄDER;ERZINGER, 2017). Estas alterações no consumo de oxigênio são associadas a alterações na alocação energética que causam prejuízo a outras funções fisiológicas, como crescimento, reprodução e desenvolvimento (CHOPELET et al, 2008;PESTANA et al, 2010;PESTANA et al, 2013;BARATA et al, 2016).…”

“…Também são verificados desvios no característico padrão de natação, na fototaxia e na busca por alimentos (MICHELS et al, 2000;MARTINS et al, 2007;REN et al, 2009;BAHRNDORFF et al, 2015;HANSEN;ROSLEV, 2016;HÄDER;ERZINGER, 2017). A fototaxia extremamente positiva da D. magna é modulada por fatores como escassez de alimento, presença de pistas químicas de predadores e xenobióticos (MICHELS et al, 2000;BURKS et al, 2002;PESTANA et al, 2010), e esta resposta facilita a detecção de estresses induzidos por xenobióticos.…”