title: Helium ion microscopy and ultra-high-resolution scanning electron microscopy analysis of membrane-extracted cells reveals novel characteristics of the cytoskeleton of Giardia intestinalis.
abstract: Giardia intestinalis presents a complex microtubular cytoskeleton formed by specialized structures, such as the adhesive disk, four pairs of flagella, the funis and the median body. The ultrastructural organization of the Giardia cytoskeleton has been analyzed using different microscopic techniques, including high-resolution scanning electron microscopy. Recent advances in scanning microscopy technology have opened a new venue for the characterization of cellular structures and include scanning probe microscopy techniques such as ultra-high-resolution scanning electron microscopy (UHRSEM) and helium ion microscopy (HIM). Here, we studied the organization of the cytoskeleton of G. intestinalis trophozoites using UHRSEM and HIM in membrane-extracted cells. The results revealed a number of new cytoskeletal elements associated with the lateral crest and the dorsal surface of the parasite. The fine structure of the banded collar was also observed. The marginal plates were seen linked to a network of filaments, which were continuous with filaments parallel to the main cell axis. Cytoplasmic filaments that supported the internal structures were seen by the first time. Using anti-actin antibody, we observed a labeling in these filamentous structures. Taken together, these data revealed new surface characteristics of the cytoskeleton of G. intestinalis and may contribute to an improved understanding of the structural organization of trophozoites.
authors.affiliation: Diretoria de Metrologia Aplicada a Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia, Rio de Janeiro, RJ, Brazil.
authors.forename: Ana Paula Rocha
authors.initials: AP
authors.lastname: Gadelha
authors.affiliation: Diretoria de Metrologia Aplicada a Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia, Rio de Janeiro, RJ, Brazil; Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil.
authors.forename: Marlene
authors.initials: M
authors.lastname: Benchimol
authors.affiliation: Diretoria de Metrologia Aplicada a Ciências da Vida, Instituto Nacional de Metrologia, Qualidade e Tecnologia, Rio de Janeiro, RJ, Brazil; Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil; Instituto Nacional de Ciência e Tecnologia em Biologia Estrutural e Bioimagens e Centro Nacional de Biologia Estrutural e Bioimagens, Universidade Federal do Rio de Janeiro, Rio de Janeiro, RJ, Brazil. Electronic address: wsouza@biof.ufrj.br.
authors.forename: Wanderley
authors.initials: W
authors.lastname: de Souza
mesh_terms: D002462:Cell Membrane / Q000648:ultrastructure; D003599:Cytoskeleton / Q000648:ultrastructure*; D005407:Flagella / Q000648:ultrastructure; D016829:Giardia lamblia / Q000648:ultrastructure*; D006371:Helium / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008870:Microtubules / Q000648:ultrastructure
chemical_list: D006371:Helium
keywords: Cytoskeleton; Giardia intestinalis; Helium ion microscopy; Membrane-extracted cells; Ultra-high-resolution scanning electron microscopy