INHIBITION OF FOOT-AND-MOUTH-DISEASE VIRUS (FMDV) UNCOATING BY A PLANT-DERIVED PEPTIDE ISOLATED FROM MELIA-AZEDARACH L LEAVES

Meliacine (MA), a peptide isolated from leaves of the high plant Melia azedarach L inhibited the multiplication of foot and mouth disease vi rus (FMDV) in BHK-21 cells. In this report, we establish that the MA-i nhibitable process takes place within the first hour of the viral repr oductive cycle. MA had no virucidal effect and did not affect adsorpti on and penetration of the virus in cells. In experiments with neutral red-labeled virus, it was found that MA significantly suppressed the d evelopment of photoresistance of the virus in infected cells. In untre ated cultures nearly all virus which adsorbed to cells was uncoated wi thin 1 h at 37 degrees C, whereas in treated cultures, even after 3 h only 3% of the virus was uncoated. Labeling of BHK-21 cells with acrid ine orange showed that MA affects the pH of intracellular acidic vesic les. Therefore, it is concluded that MA prevents the process of uncoat ing of FMDV in BHK-21 cells by inhibiting vacuolar acidification.