RESUMO
Colpodella spp. are free-living flagellates closely related to the apicomplexans. Human infections by Colpodella sp. have been reported. A biflagellated trophozoite and cyst stage comprise the known life cycle stages of Colpodella sp. However, the process of encystation and excystation within the life cycle is unclear. Life cycle stages initiating human infections are unknown. We performed a detailed investigation of the life cycle of Colpodella sp. (ATCC 50594) in culture using Sam-Yellowes trichrome stains and differential interference contrast (DIC) for light microscopy and fluorescence microscopy of Congo red-stained cells and investigated ultrastructure using transmission electron microscopy (TEM). We report previously undocumented stages of Colpodella sp. Asymmetric and asynchronous division was detected inside cysts by trichrome staining and by TEM. Odd-numbered juveniles and cysts containing more than four juvenile trophozoites were identified. Live imaging of active cultures captured the excystation and egress of juvenile trophozoites and confirmed the presence of multinucleate cysts. The ultrastructure of the multinucleate cyst is reminiscent of apicomplexan schizonts. Insights gained from the life cycle stages observed in culture allowed the construction of the life cycle of Colpodella sp. Knowledge of the life cycle will aid biochemical and molecular characterization of Colpodella sp. and help identify stages in human infections.(AU)
Assuntos
Humanos , Coloração e Rotulagem , Estágios do Ciclo de Vida , Vermelho Congo , Apicomplexa , Infecções , Pesquisa , MicrobiologiaRESUMO
In this study we performed light, immunofluorescent and transmission electron microscopy of Colpodella trophozoites to characterize trophozoite morphology and protein distribution. The use of Giemsa staining and antibodies to distinguish Colpodella life cycle stages has not been performed previously. Rhoptry and β-tubulin antibodies were used in immunofluorescent assays (IFA) to identify protein localization and distribution in the trophozoite stage of Colpodella (ATCC 50594). We report novel data identifying "doughnut-shaped" vesicles in the cytoplasm and apical end of Colpodella trophozoites reactive with antibodies specific to Plasmodium merozoite rhoptry proteins. Giemsa staining and immunofluorescent microscopy identified different developmental stages of Colpodella trophozoites, with the presence or absence of vesicles corresponding to maturity of the trophozoite. These data demonstrate for the first time evidence of rhoptry protein conservation between Plasmodium and Colpodella and provide further evidence that Colpodella trophozoites can be used as a heterologous model to investigate rhoptry biogenesis and function. Staining and antibody reactivity will facilitate phylogenetic, biochemical and molecular investigations of Colpodella sp. Developmental stages can be distinguished by Giemsa staining and antibody reactivity
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Assuntos
Trofozoítos/microbiologia , Alveolados/microbiologia , Plasmodium/microbiologia , Apicomplexa/isolamento & purificação , Infecções por Protozoários/microbiologiaRESUMO
Colpodella gonderi is the only ectoparasitic flagellate of ciliated protozoa described thus far. This investigation reveals new records of C. gonderi retrieved from soil samples in southern Scotland, UK. Of fourteen ciliates species identified in one single occasion, three of them, Colpoda steinii, Pseudoplatyophrya nana and Grossglockneria acuta, were infested with the parasite. These results provide further evidence that C. gonderi is not host-specific of the ciliate genus Colpoda (AU)
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