Ultrastructural Differences Between Species of Trypanosomatids With and Without Endosymbionts1

Abstract

Species of trypanosomatids without endosymbionts (Leptomonas seymouri, L. collosoma, L. samueli, Crithidia fasciculata, C. luciliae, C. acanthocephali, Herpetomonas megaseliae, H. mariadeanei, H. samuelpessoai, H. muscarum muscarum, Trypanosoma cruzi) and species of trypanosomatids with endosymbionts (Crithidia deanei, C. oncopelti, Blastocrithidia culicis) were comparatively studied by EM. Artificially aposymbiotic strains derived from species with symbiont were also included in the survey. Species with symbiont differ in some ultrastructural aspects from the group of species wihtout symbiont. Paraxial rods of flagella or intraflagellar structure were exclusively in species without symbiont. Peripheral branching of mitochondria, accompanied by absence of subpellicular microtubules in sites where the mitochondrial branches are appressed to the cell membrane, were exclusively in species with symbiont. Networks of kinetoplast DNA fibrils were larger and looser in species with symbiont. Symbiont-free strains of species with symbiont retained the same morphological characteristics of their parental species.