Assessment of biochemical mechanisms of tolerance to chlorpyrifos in ancient and contemporary Daphnia pulicaria genotypes

Genetic differentiation in pesticide resistance between urban and rural populations of a nontarget freshwater keystone interactor, Daphnia magna

“…using ‘naïve’ pooled populations and communities of zooplankton, Rumschlag et al, 2020 ). Evolved pesticide resistance in natural populations of Daphnia in response to agricultural pesticide application was shown both across spatial gradients (organophosphates: Bendis & Relyea, 2014 ; carbamates: Coors et al, 2009 ; Jansen et al, 2015 ) as well as in response to historical contamination (resurrection ecology, organophosphates: Simpson et al, 2017 ). Such adaptive evolutionary responses can have ecosystem‐wide buffering effects (e.g.…”

Multi‐ and Trans‐Generational Effects on Daphnia Magna of Chlorpyrifos Exposures

“…In the present study, at the highest treatment we observed an approximately 8 x tolerance (increased survival) in the F3 compared with the F1 generation. This outcome is likely due to selection for tolerant individuals in previous generations and/or chlorpyrifos‐induced tolerance (Ashauer et al, 2016; Barata et al, 2001; Simpson et al, 2017). Following a transgenerational exposure, in which only the parent (F0) generation was exposed, the unexposed F1 to F3 generations' survival and reproductive success was similar to the control (Figures 2 and 5), suggesting that by these measures, a single 21‐day chlorpyrifos exposure at environmentally relevant levels does not result in a transgenerational fitness deficit.…”

“…Biochemical tolerance response to the organophosphates includes increased AChE and butylcholinesterase (BChE) synthesis (assuming BChE is not involved in nerve signal transmission, but is a scavenger for cholinesterase inhibitors), and altered AChE less sensitive to organophosphorus inhibition (Fournier, 2005;Liu et al, 2012). Tolerance associated with phase I metabolism (Simpson et al, 2017) may result from altered activity of CYPs facilitating both an increased rate of chlorpyrifos and chlorpyrifos-oxon elimination and decreased rate of chlorpyrifos bioactivation to chlorpyrifos-oxon (Barata et al, 2001;Damásio et al, 2007;Simpson et al, 2017). Damásio et al (2007) investigated biochemical mechanisms of organophosphorus-induced tolerance by comparing two D. magna populations, a resistant population collected from rice Due to mortality, in the multigenerational assay, there were three, two, six, and nine replicates for the F0, F1, F2, and F3 generations, respectively, and in the transgenerational assay, there were 5 replicates in the F0 generation and 10 replicates in the F1, F2, and F3 generations.…”

Environmental Risk assessment of Chlorpyrifos and TCP in Aquatic Ecosystems

“…Acute and chronic exposure to common-use pesticides remains a considerable threat to non-target species, despite the continued effort to synthesize compounds with high target specificity and low environmental persistence (Simpson, Jeyasingh and Belden, 2017), in the case of Chlorpyrifos its behavior in surface water may be given by complex interactions of factors related to its application, agronomic practices, climatological conditions during and after the application, soil pedology and chemistry, hydrologic responses of drainage systems, and its physicochemical properties that affect mobility and persistence under those environmental settings (Williams et al, 2014). Chlorpyrifos may cause acute toxicity effects by inhibition of AChE occurring at low-level exposure in organisms that lack the target enzyme (Giddings et al, 2014); besides its long half-life in water, the effects of chlorpyrifos on aquatic ecosystems at different trophic levels are attracting more interest (Zhao and Chen, 2016).…”