ATPase activities of acarid mite, Tyrophagus putrescentiae (Schrank) (Acari : Acaridae), and their inhibition by several acaricides

Poisoning symptoms caused by three acaricides and one insecticide in the acarid mite, Tyrophagus putrescentiae (Schrank), were classified into two types, i. e. knock-down and immobilization. Since the immobilization was not preceded by hyper-excitation, convulsion or agony, an interference with the respiratory system was speculated. By analogy of certain acaricides known to produce similar poisoning symptoms in the two-spotted spider mite by inhibition of oligomycin-sensitive (=OS) Mg^<2+> ATPase involved in the mitochondrial respiratory enzyme system, ATPase activities and their inhibition by several compounds in the acarid mite were investigated in vitro. The mitochondrial preparation exhibited the highest activity for Na^+-K^+ ATPase, while the activity for OS Mg^<2+> ATPase was relatively low. Among several compounds tested, the selective acaricides, dicofol and cyhexatin, exhibited the highest inhibition of both ATPase activities. Bis (2,3,3,3-tetrachloropropyl) ether (=S-421) and pp'-DDT also exhibited significant but less inhibition of the enzymes. However, there was no consistent trend implicating a relation between in vitro OS Mg^<2+> ATPase inhibition and the in vivo immobilization symptom, except dicofol. With dicofol, the highest inhibition of the enzyme activity coincided with the highest immobilization symptom.