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Abstract
Giardia intestinalis, the causative agent of giardiasis, has complex cytoskeleton organization with structures involved in motility, adhesion, cell division, and cell differentiation. Microtubules are key components of the cytoskeleton and are the main elements of the ventral disc, median body, funis, in addition to four pairs of flagella. These cytoskeletal elements are basically stable microtubule arrangements. Although tubulins are the main proteins of these elements, molecular and biochemical analyses of Giardia trophozoites have revealed the presence of several new and not yet characterized proteins in these structures, which may contribute to their nanoarchitecture (mainly in the ventral disc). Despite these findings, morphological data are still required for understanding the organization and biogenesis of the cytoskeletal structures. In the study of this complex and specialized network of filaments in Giardia, two distinct and complementary approaches have been used in recent years: (a) transmission electron microscopy tomography of conventionally processed as well as cryo-fixed samples and (b) high-resolution scanning electron microscopy and helium ion microscopy in combination with new plasma membrane extraction protocols. In this review we include the most recent studies that have allowed better understanding of new Giardia components and their association with other filamentous structures of this parasite, thus providing new insights in the role of the cytoskeletal structures and their function in Giardia trophozoites.
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Emery SJ, Baker L, Ansell BRE, Mirzaei M, Haynes PA, McConville MJ, Svärd SG, Jex AR. Differential protein expression and post-translational modifications in metronidazole-resistant Giardia duodenalis. Gigascience 2018; 7:4931738. [PMID: 29688452 PMCID: PMC5913674 DOI: 10.1093/gigascience/giy024] [Citation(s) in RCA: 33] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Accepted: 03/06/2018] [Indexed: 01/20/2023] Open
Abstract
Background Metronidazole (Mtz) is the frontline drug treatment for multiple anaerobic pathogens, including the gastrointestinal protist, Giardia duodenalis. However, treatment failure is common and linked to in vivo drug resistance. In Giardia, in vitro drug-resistant lines allow controlled experimental interrogation of resistance mechanisms in isogenic cultures. However, resistance-associated changes are inconsistent between lines, phenotypic data are incomplete, and resistance is rarely genetically fixed, highlighted by reversion to sensitivity after drug selection ceases or via passage through the life cycle. Comprehensive quantitative approaches are required to resolve isolate variability, fully define Mtz resistance phenotypes, and explore the role of post-translational modifications therein. Findings We performed quantitative proteomics to describe differentially expressed proteins in 3 seminal Mtz-resistant lines compared to their isogenic, Mtz-susceptible, parental line. We also probed changes in post-translational modifications including protein acetylation, methylation, ubiquitination, and phosphorylation via immunoblotting. We quantified more than 1,000 proteins in each genotype, recording substantial genotypic variation in differentially expressed proteins between isotypes. Our data confirm substantial changes in the antioxidant network, glycolysis, and electron transport and indicate links between protein acetylation and Mtz resistance, including cross-resistance to deacetylase inhibitor trichostatin A in Mtz-resistant lines. Finally, we performed the first controlled, longitudinal study of Mtz resistance stability, monitoring lines after cessation of drug selection, revealing isolate-dependent phenotypic plasticity. Conclusions Our data demonstrate understanding that Mtz resistance must be broadened to post-transcriptional and post-translational responses and that Mtz resistance is polygenic, driven by isolate-dependent variation, and is correlated with changes in protein acetylation networks.
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Affiliation(s)
- Samantha J Emery
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia
| | - Louise Baker
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Brendan R E Ansell
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
| | - Mehdi Mirzaei
- Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, North Ryde, NSW, Australia.,Australian Proteome Analysis Facility, Macquarie University, North Ryde, NSW, Australia
| | - Paul A Haynes
- Chemistry and Biomolecular Sciences, Faculty of Science, Macquarie University, North Ryde, NSW, Australia
| | - Malcom J McConville
- Bio21 Molecular Science and Biotechnology Institute, The University of Melbourne, Melbourne, VIC, Australia
| | - Staffan G Svärd
- Department of Cell and Molecular Biology, Uppsala University, Uppsala, Sweden
| | - Aaron R Jex
- Population Health and Immunity Division, Walter and Eliza Hall Institute of Medical Research, Melbourne, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, The University of Melbourne, Melbourne, VIC, Australia
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Schwarz RS, Bauchan GR, Murphy CA, Ravoet J, de Graaf DC, Evans JD. Characterization of Two Species of Trypanosomatidae from the Honey Bee Apis mellifera: Crithidia mellificae Langridge and McGhee, and Lotmaria passim n. gen., n. sp. J Eukaryot Microbiol 2015; 62:567-83. [PMID: 25712037 DOI: 10.1111/jeu.12209] [Citation(s) in RCA: 114] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2014] [Revised: 12/16/2014] [Accepted: 12/21/2014] [Indexed: 01/03/2023]
Abstract
Trypanosomatids are increasingly recognized as prevalent in European honey bees (Apis mellifera) and by default are attributed to one recognized species, Crithidia mellificae Langridge and McGhee, 1967. We provide reference genetic and ultrastructural data for type isolates of C. mellificae (ATCC 30254 and 30862) in comparison with two recent isolates from A. mellifera (BRL and SF). Phylogenetics unambiguously identify strains BRL/SF as a novel taxonomic unit distinct from C. mellificae strains 30254/30862 and assign all four strains as lineages of a novel clade within the subfamily Leishmaniinae. In vivo analyses show strains BRL/SF preferably colonize the hindgut, lining the lumen as adherent spheroids in a manner identical to previous descriptions from C. mellificae. Microscopy images show motile forms of C. mellificae are distinct from strains BRL/SF. We propose the binomial Lotmaria passim n. gen., n. sp. for this previously undescribed taxon. Analyses of new and previously accessioned genetic data show C. mellificae is still extant in bee populations, however, L. passim n. gen., n. sp. is currently the predominant trypanosomatid in A. mellifera globally. Our findings require that previous reports of C. mellificae be reconsidered and that subsequent trypanosomatid species designations from Hymenoptera provide genetic support.
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Affiliation(s)
- Ryan S Schwarz
- Bee Research Laboratory, Beltsville Agricultural Research Center - East, U.S. Department of Agriculture, Bldg 306, 10300 Baltimore Ave., Beltsville, MD, 20705, USA
| | - Gary R Bauchan
- Electron and Confocal Microscopy Unit, Beltsville Agricultural Research Center - West, U.S. Department of Agriculture, Bldg 012, 10300 Baltimore Ave., Beltsville, MD, 20705, USA
| | - Charles A Murphy
- Electron and Confocal Microscopy Unit, Beltsville Agricultural Research Center - West, U.S. Department of Agriculture, Bldg 012, 10300 Baltimore Ave., Beltsville, MD, 20705, USA
| | - Jorgen Ravoet
- Laboratory of Zoophysiology, Faculty of Science, Ghent University, Ghent, Belgium
| | - Dirk C de Graaf
- Laboratory of Zoophysiology, Faculty of Science, Ghent University, Ghent, Belgium
| | - Jay D Evans
- Bee Research Laboratory, Beltsville Agricultural Research Center - East, U.S. Department of Agriculture, Bldg 306, 10300 Baltimore Ave., Beltsville, MD, 20705, USA
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