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Observations on the Life Cycle of Phytomonas elmassiani (Migone) in East Africa
Author(s) -
VICKERMAN KEITH
Publication year - 1962
Publication title -
the journal of protozoology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 0022-3921
DOI - 10.1111/j.1550-7408.1962.tb02575.x
Subject(s) - midgut , flagellate , biology , budding , insect , parasite hosting , microbiology and biotechnology , salivary gland , larva , botany , zoology , biochemistry , world wide web , computer science
SYNOPSIS. A leptomonad flagellate found in large numbers in the latex of the asclepiad plant Pergularia extensa in East Africa has been identified as Phytomonas elmassiani (Migone). The flagellate is believed to undergo cyclical development in the lygaeid bug Oncopeltus famelicus which feeds on Pergularia. Following the ingestion of infected latex by the insect, the flagellates on reaching the midgut enter a growth phase and increase in size to form giant leptomonads. These probably then migrate to the salivary glands of the bug, possibly by boring through the gut wall, haemocoel and walls of the salivary glands. The salivary gland forms represent a multiplication phase in the life‐cycle, and numerous small metacyclic forms are produced which are then injected into a plant host to initiate a new infection. Also infecting the midgut of Oncopeltus famelicus is another trypanosomatid, Blastocrithidia familiaris (Gibbs). It is characterised by the possession of an undulating membrane and the habit of budding off leishmania bodies from its anterior end. These bodies are resistant and serve in the transmission of the parasite from bug to bug. The two flagellates of Oncopeltus famelicus are readily distinguished from one another, not only on morphological grounds but also on their behaviour in vitro. B. familiaris can be cultivated on a monophasic glucose‐peptone broth. It then loses its undulating membrane but retains its budding habit. Phytomonas elmassiani will not grow on this medium but when inoculated into a diphasic peptone blood‐agar medium the latex forms will undergo development comparable to their insect midgut phase. The plant trypanosomatids appear to form a well‐defined group bearing little similarity to the monogenetic insect flagellates of the “crithidia” type. It is suggested that the culture form Strigomonas (= Crithidia ) oncopelti , allegedly parasitic in asclepiads and Oncopeltus fasciatus , might be simply an insect parasite, its original plant association being quite fortuitous.