B-esterase activities and blood cell morphology in the Frog Leptodactylus chaquensis (Amphibia: Leptodactylidae) on rice agroecosystems from Santa Fe Province (Argentina).

A. M. ATTADEMO; CABAGNA M. C.; LAJMANOVICH R. C.; P. M. PELTZER; C. M. JUNGES; BASSÓ A

ECOTOXICOLOGY

SPRINGER

Año: 2011 vol. 20 p. 274 - 282

0963-9292

Activity of B-esterases (BChE: butyrylcholinesteraseand CbE: carboxylesterase using two model substrates:a-naphthyl acetate and 4-nitrophenyl valerate) in anative frog, Leptodactylus chaquensis from rice fields(RF1: methamidophos and RF2: cypermethrin and endosulfansprayed by aircraft) and non-contaminated area(pristine forest) was measured. The ability of pyridine-2-aldoxime methochloride (2-PAM) to reactivate BChElevels was also explored. In addition, changes in blood cellmorphology and parasite infection were determined. Meanvalues of plasma BChE activities were lower in samplesfrom the two rice fields than in those from the referencesite. CbE (4-nitrophenyl valerate) levels varied in the threesites studied, being highest in RF1. Frog plasma from RF1showed positive reactivation of BChE activity after incubationwith 2-PAM. Blood parameters of frogs from RF2revealed morphological alterations (anisochromasia andimmature erythrocytes frequency). Moreover, a majorinfection of protozoan Trypanosoma sp. in individualsfrom the two rice fields was detected. We suggest thatintegrated use of several biomarkers (BChE and CBEs,chemical reactivation of plasma with 2-PAM, and bloodcell parameters) may be a promising procedure for use inbiomonitoring programmes to diagnose pesticide exposure