Acetylcholinesterase Inhibition and Altered Locomotor Behavior in the Carabid Beetle Pterostichus Cupreus. A Linkage Between Biomarkers at Two Levels of Biological Complexity

Abstract

Abstract-The establishment of cause-effect relationships is fundamental for the interpretation and the predictive value of biomarker responses measured at all levels of biological complexity. In the present study, the biochemical exposure biomarker acetylcholinesterase (AChE) inhibition was related to locomotor behavior, representing a general effect biomarker at the organismal level. Both sexes of the carabid beetle Pterostichus cupreus were intoxicated with three doses of the organophosphorous insecticide dimethoate. Five elements of their locomotor behavior were measured for 4 h employing computer-aided video tracking, whereupon the whole body AChE activity was measured in the individual beetle. AChE inhibition was strongly correlated with dimethoate dose in both sexes. Alterations in the locomotor behavior were directly correlated with AChE inhibition in male beetles, which responded by reducing the time in locomotion, average velocity, and path length and by increasing the turning rate and frequency of stops. Females responded similarly at the two highest doses, whereas their locomotor behavior was not significantly different from the control group at the lowest dimethoate dose, suggesting a sex-dependent difference in behavioral sensitivity to minor AChE depressions. The results demonstrate that automated measurements of locomotor behavior is at least as sensitive an endpoint to organophosphate poisoning as the AChE assay. Further, the correlation between the molecular and behavioral responses in individual beetles indicates a mechanistic relationship between the two biomarkers.

An In Situ Bioassay Integrating Individual and Biochemical Responses Using Small Fish Species

“…Taylor et al (1998) suggested gut poisoning as the toxicity mechanism of cadmium in feeding-impaired Daphnia. The inhibition of AChE is responsible for an impairment of neuronal and neuromuscular function, and could also affect the feeding behavior of the fish (Dell'Omo et al, 1997;Jensen et al, 1997;Beauvais et al, 2000;Brewer et al, 2001). However, in the present study, feeding impairment was observed where no AChE inhibition occurred (site S1).…”

“…This approach is not new, although previous studies have only exploited individual biomarkers, based on some sort of underlying physiological mechanism, such as AChE inhibition and behavioral changes (Dell'Omo et al, 1997;Jensen et al, 1997;Beauvais et al, 2000;Brewer et al, 2001). Pelletier et al (1995) have shown a strong positive relationship between glycolytic enzymes (including LDH) and growth rate, but did not study the response of this association to toxicants.…”

Locomotor activity and respiration rate of the ground beetle, Pterostichus oblongopunctatus (Coleoptera: Carabidae), exposed to elevated nickel concentration at different temperatures: novel application of Multispecies Freshwater Biomonitor®

“…The use of locomotor endpoints in toxicity testing concerns mainly effects of pesticides on terrestrial invertebrates (e.g., Sørensen et al 1995;Jensen et al, 1997;Engenheiro et al, 2005;Desneux et al, 2007). We have not found studies of Ni effects on behavior in any invertebrates, but in those few ecotoxicological studies in which effects of different metals were investigated in terrestrial invertebrate species, both hyperactivity and hypoactivity were observed.…”

“…The sublethal effects are much more sensitive measures in detecting contamination than measurements of survival alone and may be applied in bioassays to detect or monitor the presence of contaminants in the environment. Since the animal locomotor behavior was suggested as a sensitive and noninvasive biomarker of sublethal chemical stress caused by a variety of pollutants (pesticides in particular), a substantial amount of such information on terrestrial invertebrates has become available (e.g., Sørensen et al 1995;Laskowski et al 1996;Bayley et al 1997;Jensen et al 1997;Sørensen et al 1997;Engenheiro et al 2005).…”

Acute and sublethal effects of sequential exposure to the pesticide azinphos-methyl on juvenile earthworms (Eisenia andrei)

“…As organophosphates inhibit cholinesterase activity and therefore the normal transfer of nerve impulses, they can cause abnormal functioning of the nervous system and are likely to have an effect on the mobility, activity and behaviour of affected organisms. Organophosphate-induced changes in behaviour have been the subject of a number of studies in invertebrate and vertebrate species including nematodes (Anderson et al 2004), beetles (Jensen et al 1997), fish (Scott and Sloman 2004) and small mammals (Dell'Omo et al 2003). Avoidance behaviour is a well-studied endpoint in various earthworm species following exposure to a number of contaminants (Slimak 1997;Capowiez et al 2003;Loureiro et al 2005).…”