Unusual axonemal doublet arrangements in the flagellum of Leishmania amastigotes.

Studies on the fine structure of Leishmania mexicana, L. enriettii and L. tropica major have revealed several unusual arrangements of microtubules in the flagellar axoneme. The anterior end of the flagellum in these three species was found to contain disarranged axonemal doublets (d) in the absence of the two central singlets(s). Leishmania amastigotes do not use their flagellum as do promastigotes for propulsion, and persistence of the usual 9d and 2s microtubular arrangement may not be necessary.