Culture and Generic Identification of Trypanosomatids of Phytophagous Hemiptera in Brazil

Among the 372 phytophagous Hemiptera examined, 133 insects of 28 species (Coreidae 18, Pentatomidae 7, Pyrrhocoridae 2, Lygaeidae 1) were infected with trypanosomatids. Gut infections only were found in 68.4%, gut and salivary gland infections in 29.3% and salivary infections alone in 2.3%. Fifty-one cultures were isolated from 38 insects. Cultures were characterized by assay of certain ornithinc-arginine metabolism enzymes and by indirect immunofluorescence against monoclonal antibodies specific for Phytomonas spp. Ten cultures were identified as either Crithidia or Leptomonas. Twenty-one promastigote cultures had an enzyme pattern hitherto recorded only for Leishmania and 16 cultures were identified as Phytomonas.     

Life Cycle and Culturing of Phytomonas serpens (Gibbs), a Trypanosomatid Parasite of Tomatoes

Pure cultures of a trypanosomatid isolated from tomato fruits infected laboratory-raised tomatoes and nymphs of the hemipieran coreid Phthia picta . The flagellate could be transmitted back and forth from tomatoes to insects. Light and electron microscopy studies were done on culture, tomato and insect forms. Examination of enzymes of the ornithine-arginine metabolism revealed absence of arginase and presence of arginine deiminase and citrulline hydrolase. Monoclonal antibodies specific for Phytomonas spp. reacted positively with tomato and insect forms. Endonuclease digestion of the k-DNA of various Phytomonas spp. revealed a unique, distinctive pattern for the tomato flagellate. This flagellate thus seems to constitute a separate species of Phytomonas which we now call Phytomonas serpens (Gibbs).     

Trypanosomatids, Other Than Phytomonas spp., Isolated and Cultured from Fruit

Trypanosomatids were isolated from edible fruit. One of the isolates (from tangerine) presented a set of enzymes for the metabolism of arginine-ornithine similar to that of Leptomonas spp., and failed to be recognized by monoclonal antibodies specific for Phytomonas spp. The possibility that trypanosomatids other than Phytomonas spp. could infect fruit was further examined by inoculating tomatoes with species of Crithidia, Leptomonas and Herpetomonas. Some of these flagellates multiplied in tomatoes. Besides, house flies became infected with Crithidia sp. when fed on tomatoes experimentally inoculated with this flagellate. Therefore, isolation of a trypanosomatid from a plant should not constitute an absolute criterion for placing it in the genus Phytomonas.