On few occasions, Phytomonas davidi (McGhee & Postell isolate) cultures in
LIT (liver infusion-tryptose) medium around 27 C presented, as seen in
Giemsa-stained smears, a set of peculiar morphological features, among them
being noticeable the pairs of apposed cells attached by their posterior
ends, where occurred a stained line and/or a dilatation, usually bulb-like
in shape; sometimes this dilatation could occupy one of the cells or hold
both together. In some pairs, the nucleus of each parasite seemed migrating
towards the other, entering into such dilatation; in others, both nuclei
were inside it, sometimes in close proximity or seeming fused; peculiar
chromatin arrangements involving both nuclei were occasionally observed.
Several mono or binucleate round forms bearing one or two flagella, as well
as flagellate slender cells without nucleus were concomitantly seen there.
In some instances, an intriguing small stained body occurred beside a
single large nucleus, either in pairs presenting the bulb-like structure or
in round cells. These cytological findings seemed steps of a dynamic
process suggesting sexuality, since in several of them nuclear interactions
following fusion of two parasites appeared to occur.