title: Leishmania pifanoi: kinetics of messenger RNA expression during amastigote to promastigote transformation in vitro.
abstract: Conditions have been developed which induce axenically grown Leishmania pifanoi amastigotes to transform into the promastigote stage in a highly reproducible fashion. Transformation was induced by a temperature shift from 31 to 22 degrees C, was inhibited by high cell concentration (> or = 40 x 10(6) cells/ml), and was unaffected by pH from 5.5-7.2. Morphologic transformation was first evident at 8 hr after induction, had occurred in > 50% of cells by 24 hr, and was > 90% complete by 48 hr. This system enabled study of the kinetics of mRNA expression during the transformation of Leishmania. The differentially expressed mRNAs for ATPase 1a and 1b, alpha- and beta-tubulin, P100/11E, Pro-1, and pLm 2, 7, 14, and 16 exhibited complex patterns of temporal expression, suggesting a highly regulated process. Differentiation on the biochemical level was evident within an hour and continued throughout the course of morphologic transformation. In addition, transformed L. pifanoi promastigotes in the plateau growth phase expressed genes characteristic of metacyclic promastigotes. Axenically cultured L. pifanoi should provide an excellent model for the study of differentiation in Leishmania.
authors.affiliation: Department of Laboratory Medicine, Yale University School of Medicine, New Haven, Connecticut 06504.
authors.forename: S M
authors.initials: SM
authors.lastname: Campbell
authors.forename: P M
authors.initials: PM
authors.lastname: Rainey
mesh_terms: D000251:Adenosine Triphosphatases / Q000235:genetics; D000818:Animals; D015870:Gene Expression; D017125:Genes, Protozoan; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007891:Leishmania / Q000166:cytology* / Q000235:genetics / Q000254:growth & development; D015800:Protozoan Proteins / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D016053:RNA, Protozoan / Q000235:genetics* / Q000378:metabolism; D013696:Temperature; D014404:Tubulin / Q000235:genetics
chemical_list: D015800:Protozoan Proteins; D012333:RNA, Messenger; D016053:RNA, Protozoan; D014404:Tubulin; D000251:Adenosine Triphosphatases