Platelet lysis and functional perturbation by 13-methyl myristate. The major fatty acid in Flavobacterium ranacida.

Flavobacterium ranacida consisted of 75% of 13-methyl myristate in total fatty acids. The acid at > 60 microM caused the lysis of gel-filtered platelets (GFP) in both time- and concentration-dependent manners. Scanning electron microscopy showed that: 1). GFP in 40 microM of the acid changed the morphology to speculate discoid shape at 15 sec, and to ellipsoids after 30 sec; and 2), the cells gradually swelled to spherical forms as the concentration of the acid increased. At nonlytic concentration, the acid inhibited platelet responses to various agonists with differential concentrations. The order of inhibitory potency was U46619 > low dose collagen > ADP-fibrinogen > phorbol ester > high dose collagen. The results demonstrated that 13-methyl myristate exhibited both cell lytic activity and perturbation on membrane function.