Isolation of western X mycoplasmalike organism from infectious extracts of leafhoppers and celery

Extracts from both Western X-diseased leafhoppers, C. montanus, and from celery were centrifuged on a density gradient column formed from successive layering 1.3, 1.1, 0.9, and 0.7 M sucrose in a complex buffer. Three zones, A, B, and C, were obtained. The percentage of leafhoppers infected by injecting material from zone A, B, and C, was 72, 85, and 65, respectively when using the leafhopper extract. No infectivity was detected in any zones from the celery extract.Thin sections of material from each of the zones were examined with the electron microscope. The large spherical electron transparent bodies, typical of Western X mycoplasmalike bodies found in diseased tissue, was most concentrated in the B zone of the leafhopper extract.