Effects of anion and cation inhibitors and carbonic anhydrase inhibitors upon the activity of the gypsy moth (Lepidoptera: Lymantriidae) nucleo-polyhedrovirus.

Twenty chemicals that were reported to act as anion transport inhibitors, cation transport inhibitors, and inhibitors of carbonic anhydrase activity were tested at a 1% concentration (wt:wt) for their effects upon the biological activity of the gypsy moth, Lymantria dispar (L.), nucleopolyhedrovirus (LdMNPV). Among the five anion transport inhibitors tested, flufenamic acid acted as a viral enhancer. None of the seven inhibitors of K+ enhanced viral activity and three (4-aminopyridine, diacetyl, and procaine) significantly reduced the activity of LdMNPV. All four Na+ transport inhibitors (abietic acid, amiloride, dicyclohexylcarbodiimide, triamterene) acted as viral enhancers. Triamterene was the most active enhancer, as the LC50 was reduced by approximately 1,750-fold. Five carbonic anhydrase inhibitors were tested and four (acetazolamide, hydrochlorothiazide, methazolamide, sulfanilamide) enhanced the activity of LdMNPV. Acetazolamide (a carbonic anhydrase inhibitor), amiloride (a Na+ transport inhibitor), and flufenamic acid (an anion transport inhibitor) were tested singly and in different combinations. Every combination tested (acetazolamide/amiloride, acetazolamide/flufenamic acid, amiloride/flufenamic acid, acetazolamide/amiloride/flufenamic acid) significantly decreased the LC50 from 7.79 PIB/mm2 to a value as low as 0.008 PIB/mm2 (amiloride/flufenamic acid).