Evaluation of sensitivity and specificity of two crustacean biochemical biomarkers

Abstract

Abstract-Biochemical biomarkers are increasingly used for environmental assessment. Although the emphasis has been on vertebrate biomarkers, invertebrates biomarkers have been developed as well. This study evaluated the usefulness of biomarker responses of freshwater invertebrates by comparing the sensitivity and specificity of endpoints at three levels of biological organization: biochemical, physiological, and individual. The study focused on the epibenthic amphipod Gammarus pulex L., and the end points were cholinesterase (ChE) and glutathione-S-transferase (GST) activity, feeding inhibition, and mortality. Chemicals representing five major classes of toxic chemicals were assessed, including zinc, linear alkylbenzene sulphonate (LAS; surfactant), lindane (organochlorine), pirimiphos-methyl (organophosphorus), and permethrin (pyrethroid). Lethality was the least sensitive endpoint, with 96-h LC50 values ranging from 2.78 g/L for permethrin to 6.31 mg/L for LAS. Comparison of the biochemical biomarkers and the sublethal feeding rate assay indicated that whereas ChE inhibition was a specific indicator of organophosphate exposure, the biochemical assay was more than 13-fold less sensitive than the feeding rate assay. The GST biomarker performed with greater sensitivity but with lower specificity compared with the ChE biomarker. However, only on exposure to lindane did the GST biomarker marginally outperform the feeding rate assay in terms of sensitivity. Feeding inhibition is both a general and a sensitive (LC50, Ͻ3%) indicator for exposure to a range of chemicals. The Gammarus sp. ChE biomarker may have utility in providing a diagnostic and rapid indicator of organophosphate exposure, but evidence from this and other studies questions the sensitivity of this biomarker in predicting sublethal, higher-order effects. The GST biomarker may provide a rapid and sensitive indicator for toxicant exposure, but it has limited use as a diagnostic tool and provides only limited improvement in sensitivity over more ecologically relevant sublethal end points (e.g., feeding rate, growth rate).

Cholinesterase and glutathione-S-transferase activities in freshwater invertebrates as biomarkers to assess pesticide contamination

“…For the crustacean group, a large number of publications refer to a concentration-dependent inhibition of ChE with OP and carbamate pesticides (Supplemental Data, Table S1). This has been documented for Daphnia magna [30][31][32][33][34], Gammarus pulex [4], Hyalella azteca [35], and Procambarus clarkii [36] with several OPs and carbamates. These observations are in accordance with the expectations based on the mode of action of carbamates and OP pesticides.…”

“…The biomarker approach, adopted from medical toxicology, is based on the assumption that low concentrations of a toxicant will cause a biochemical response within an organism before detrimental effects are observed at higher levels of biological organization. However, its use has presented difficulties for interpretation, namely, to what extent a biomarker response can be reliably linked to an environmental effect of ecological relevance [4,5]. Generally, biomarkers can be defined as a pathway-or a receptor-specific endpoint that can be considered a measurable stressor-induced variation in biochemical, physiological, and morphological status of an organism [6].…”

Biomonitoring of lake sediments using benthic macroinvertebrates

“…Inhibition of ChE activity has been proposed as an effective tool for monitoring the exposure of organisms to organophosphorus and carbamate pesticides, whereas induction of GST can be suggestive of exposure to organochlorine compounds. McLoughiln et al [40] have used these biomarkers, together with mortality and feeding inhibition, to assess the potential risk of major classes of toxic chemicals (i.e. metals, surfactants, organochlorine, organophosphorus, and pyrethroid pesticides) to amphipod Gammarus pulex.…”

Effects of pesticides and antibiotics on penaeid shrimp with special emphases on behavioral and biomarker responses

“…Feeding depression has been found as a sensitive endpoint for measuring the response of the organism to chemical exposure [21]. Food is the basic requirement for growth and other physiological functions of the body [22].…”

“…Food is the basic requirement for growth and other physiological functions of the body [22]. Feeding rate has been proposed in several studies as a sensitive indicator of toxic stress in both freshwater and marine species [23][24][25]. García de la Parra et al [20] observed that, in whiteleg shrimp (Litopenaeus vannamei) exposed to sublethal concentrations of 0.66, 0.83, 1.01, 1.18, and 1.35 mg/L methamidophos for 24 h under the experimental conditions of 258C, 32 ppt, 12:12 h light:dark photoperiod, the feeding rate did not show significant differences among treatments.…”