Cell Differentiation, 22 (1988) 165-170 Elsevier Scientific Publishers Ireland, Ltd. 165 CDF 00465 Influence of saccharides and sodium chloride on growth and differentiation of Trypanosoma cruzi F.J. Adroher l, J.A. Lupifihez 2 and A. Osuna l Departments of j Parasitology and 2 Bi'ochemistry and Molecular Biology, University of Granada, 18001.Granada, Spain (Accepted 8 July 1987) The influence of saccharides, especially glucose and fructose, on the metacyclogenesis and growth of Trypanosoma cruzi has been investigated. In the absence of glucose and fructose in the media, both the percentage of metacyclic forms and the growth increased significantly. Furthermore, the addition of NaCI to the medium without monosaccharides strongly increased the formation of metacyclic forms. Presence of NaCI and absence of monosaccharides showed a synergic effect on differentiation of T. cruzi. Trypanosoma cruzi; Differentiation; Metacyclogenesis; Growth; Monosaccharide; Sodium chloride Introduction Trypanosoma cruzi, a protozoan parasite, is the causative agent of Chagas' disease or American trypanosomiasis. This flagellate has a life cycle involving mammalian and insect hosts. In the insect vectors (Reduviidae, Hemiptera), the cycle of development takes place in the intestinal tract of the host. Typical trypomastigote forms inggsted by the insect become epimastigotes which undergo division. After about 8 to 15 days, metacyclic trypomastigotes, developed from epimastigote forms, appear in the rectum. These metacyclic forms, which do not replicate, pass into feces and urine and are infective to man and reservoir animals when rubbed into the puncture wound made by the insect or into an abrasion of the skin. Metacyclic forms invade mammalian host cells, where they transform, before replication, into Correspondence address: Dr. F.J. Adroher, Departamento de Parasitologia, Facultad de Farmacia, Universidad de Granada, 18001-Granada, Spain. amastigotes. Amastigotes multiply and differenti- ate into trypomastigotes which are liberated into the intercellular spaces and the bloodstream. The non-dividing trypomastigotes either invade new cells or may be ingested by the triatomine insect. The differentiation processes occurring during the life cycle of 7". cruzi are not well known. The transformation from amastigote to epimastigote and trypomastigote forms was investigated by Williams (1983, 1984, 1985), who observed that inhibition of ADP-ribosyl transferase (ADPRT) activity blocks this differentiation. ADPRT activ- ity is also an obligatory requirement in the cyto- differentiation of some higher eukaryotic cells (Farzaneh et al., 1982). The differentiation from epimastigote to meta- cyclic forms, also called metacyclogenesis, has been frequently studied. Some factors have been cited as stimulators or inhibitors of this process; among these are the strain or clone utilized (Crane and Dvorak, 1982; Garcia and Dvorak, 1982), the duration of the in vitro cultures (Chiari, 1974), presence of lectins in the insect gut (Pereira et al., 0045-6039/88/$03.50 © 1988 Elsevier Scientific Publishers Ireland, Ltd.