Toxic effects of chlorpyrifos on morphology and acetylcholinesterase activity in the earthworm, Eisenia foetida.
The acute toxicity of chlorpyrifos (O, O-diethyl-O-(3,5,6-trichloro-2-pyridyl) phosphorothioate) was determined in the earthworm, Eisenia foetida. A 48-h contact test as described by the Organization for Economic Cooperation and Development (OECD) guideline 207 was carried out. The LC(50) of chlorpyrifos was 0.063 microg/cm(2). Inhibition of acetylcholinesterase (AChE: EC 3.1.1.7) activity indicated by in vitro neurotoxic potentiality revealed competitive inhibition and altered K(m) values widely in a dose-dependent manner. The K(i) value of chlorpyrifos was 4.20 x 10(-6)M. AChE activity of LC(50)-exposed worms was 62%, 79%, 85%, and 91% inhibited at 12, 24, 36, and 48h, respectively. Scanning electron microscopic studies revealed the morphological abnormalities in the worms. The present study demonstrates a dose- and time-dependent exposure of chlorpyrifos through skin results, morphological abnormalities, and inhibition of AChE in the earthworm, E. foetida.
Venkateswara Rao
J
J
Toxicology Unit, Biology Division, Indian Institute of Chemical Technology, Hyderabad 500 007, India. jv@iict.ap.nic.in
Surya Pavan
Y
Y
Madhavendra
S S
SS
D000110:Acetylcholinesterase / Q000494:pharmacology*; D000818:Animals; D004390:Chlorpyrifos / Q000633:toxicity*; D000013:Congenital Abnormalities / Q000209:etiology / Q000662:veterinary; D007306:Insecticides / Q000633:toxicity*; D008855:Microscopy, Electron, Scanning; D009835:Oligochaeta / Q000033:anatomy & histology* / Q000502:physiology*; D012989:Soil Pollutants / Q000633:toxicity*
D007306:Insecticides; D012989:Soil Pollutants; D000110:Acetylcholinesterase; D004390:Chlorpyrifos