ATP-binding cassette (ABC) efflux pumps mediate the activity of the Multixenobiotic Resistance (MXR) mechanism and have been proposed as a biomarker of environmental pollution mainly in aquatic invertebrates. MXR activity was never investigated in Collembola and represents a potential tool for soil biomonitoring. This study aimed to characterize for the first time the activity of ABC efflux pumps in the gut of collembolan species, and investigate its responsiveness to cadmium (Cd), a common stressor found in polluted soils. We performed in vitro rhodamine-B accumulation assays in the presence of model inhibitors of ABC efflux pumps: verapamil hydrochloride as P-gp (P-glycoprotein) inhibitor, and MK571, as MRPs (multidrug resistance-related proteins) inhibitor. We also performed rhodamine-B accumulation assays under Cd-exposure (209 μg/L;1 μM). Our results showed that all species presented basal (noninduced) level of MXR activity in their gut. Efflux pumps P-gp and/or MRPs activity were confirmed in Cyphoderus innominatus, Cyphoderus similis, and Folsomia candida, the standard species. The rhodamine-B accumulation assays performed with Cd, applied as soil pollutant, showed that the gut of non-standard species C. similis and Trogolaphysa sp. presented an increase of MXR activity for both P-gp and MRP transporters, indicating the potential of these species as test organisms for soil ecotoxicology studies in Neotropical region. Our findings suggest a functional role of ABC transporters in the collembolan gut and their cellular involvement in Cd defense response, corroborating that MXR phenotype in Collembola can be a promising tool for bioindication of soil contamination.

ATP结合盒（ABC）外排泵介导了多异生物抗性（MXR）机制的活动，并已被提议作为主要在水生无脊椎动物中污染环境的生物标志物。Collembola从未研究过MXR活性，它代表着土壤生物监测的潜在工具。这项研究的目的是首次表征collembolan物种肠道中的ABC外排泵的活性，并研究其对镉（Cd）的反应能力，镉是在污染土壤中常见的应激源。我们在体外进行在ABC外排泵模型抑制剂存在下的罗丹明B积累测定：盐酸维拉帕米作为P-gp（P-糖蛋白）抑制剂，MK571作为MRP（与多药耐药相关的蛋白）抑制剂。我们还进行了Cd暴露（209μg/ L; 1μM）下的若丹明B积累测定。我们的结果表明，所有物种在其肠道中均表现出基础（非诱导）水平的MXR活性。在标准物种Cyphoderus innominatus，Cyphoderus similis和Folsomia candida中确认了外排泵的P-gp和/或MRPs活性。用镉作为土壤污染物进行的罗丹明B累积测定表明，非标准物种C的肠道。似ili和Tro草sp。提出了P-gp和MRP转运蛋白的MXR活性增加，表明这些物种作为新热带地区土壤生态毒理学研究的测试生物的潜力。我们的发现表明ABC转运蛋白在collembolan肠中的功能性作用及其在Cd防御反应中的细胞参与，证实了Collembola中的MXR表型可以成为土壤污染生物指示的有前途的工具。