Ultrastructural analysis of Phytomonas species from Euphorbia pinea reveals trans-cytoplasmic filaments 10 nm in diameter

Phytomonas sp. derived from Euphorbia pinea are digenetic plant trypanosome s that are transmitted by the squashbug Stenocephalus agilis and exist excl usively as promastigotes. The stable sub-pellicular microtubular array, the flagellar axoneme and the paraflagellar rod represent the major cytoskelet al components common to all trypanosomes. The work described in this paper examines in detail the ultrastructural morphology of the organism and highl ights a number of novel structural features, and in particular, the presenc e of some detergent-resistant proteins which take the form of bundles of tr ans-cytoplasmic filaments of ca, 10 nm in diameter, seen in cells from both log- and stationary-phase cultures. The ultrastructural morphology and imm unological cross-reactivity of these filaments are described, and their rel ationship to filamentous bundles previously reported in stationary-phase cu ltures of Crithidia fasciculata and to intermediate filaments of animal cel ls is discussed.