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There is an error in the ventral disc description of Giardia lamblia. The ventral disc of Giardia lamblia is a right-handed spiral array. Figure 3 legend is incorrect as a result of this error. Please view the correct Figure 3 legend, updated Figure 1, Figure 3, Figure S1, Video S1, Video S2, Video S3, and Video S4, which contains a right-handed spiral array on this page.
Additionally, there are some errors in the “Introduction” and “Results” section as a result of the above modification. The correct sentences are listed below:
The second sentence of the third paragraph of the “Introduction” section should read:
“The ventral disc is composed of a right-handed spiral array of parallel microtubules and tightly associated microribbons (Figure 1D) [9–12] that is surrounded by a fibrillar structure called the lateral crest (Figure 1A; LC).”
The fourth sentence of the second paragraph of the sub-heading “Whole cell reconstruction of a Giardia trophozoite illustrates the highly structured 3-D architecture of the microtubule cytoskeleton” of the “Results” section should read :
"The majority of the microtubule-microribbon complexes originates from a series of dense bands at a region near the caudal and posterior-lateral basal bodies (Figure 1E) and form a right-handed spiral (Figure 3A).”
The seventh sentence of the second paragraph of the sub-heading "Whole cell reconstruction of a Giardia trophozoite illustrates the highly structured 3-D architecture of the microtubule cytoskeleton" of the “Results” section should read:
"Occasionally, an array of microtubules called "supernumerary microtubules" [9], which lack associated microribbons and form a short left-handed spiral fragment (Figure 1F)."
Supporting Information
Figure S1
Cryo-electron tomography of ventral discs. A) Isolated cytoskeleton with the ventral disc (VD) and all eight flagella (AFL, CFL, PFL, VFL) present. Areas suitable for cryo-tomography are over the hole in the carbon (box). B) A schematic representation of the ventral disc showing the location of each tomogram used in this study (1–5). Adapted with permission from [11]. C–G) Tomographic slices from each of the tilt-series used to generate the grand average (C, Tomo-1; D, Tomo-2; E, Tomo-3; F, Tomo-4; G, Tomo-5). The left panel is a 25 nm slice through the microtubules and the right panel is a 50 nm slice through the microribbons. Each tomogram is shown with its original orientation with the tilt-axis vertical. In all cases, the 8 nm repeat on the microtubule is obvious (arrow in F, left panel), but the crossbridges between adjacent microribbons are only sometimes seen clearly (arrow in F, right panel). Plus-end and margin directions are indicated. Scale bars in A = 2 µm, C–G = 100 nm.
Whole-cell reconstruction of an attached Giardia intestinalis trophozoite using 3View®. Each slice was obtained using a microtome inside a scanning electron microscope. After each section was removed, a backscatter-signal scanning electron micrograph was recorded [18]. IMOD [56] was used to model important features of the cytoskeleton and attachment sites. Each slice is 70 nm. The majority of organelles are visible with this method: Plasma membrane (grey), median body (orange), nuclei (brown), ventral disc (green), anterior flagella (purple), caudal flagella (cyan), posterior-lateral flagella (blue), and ventral flagella (magenta). Near the ventral portion of the cell, important components of attachment are seen (bare area, lateral crest, lateral shield). Scale bar, 2 µm.
Whole-cell reconstruction model showing relationships between cytoskeletal elements. The Video starts with the raw data, then transitions into the modeled data created by IMOD [56]. The ventral portion of the cell contains most of the cytoskeletal elements—the ventral disc (VD), median body (MB), and 4 pairs of flagella (anterior flagella, AFL; caudal flagella, CFL; posterior-lateral flagella, PFL; ventral flagella, VFL) as well as the two nuclei (N). The bulk of the cytoskeletal elements are at the ventral portion of the cell–the attachment site to the host microvili. Scale bar, 2 µm.
Tomographic reconstruction of 3 serial-montaged sections of a Giardia trophozoite. Each slice is 3 nm in the Z-plane. The transition zone between sections looks like a jump. Anterior flagella, AFL (purple); caudal flagella, CFL (cyan); posterior-lateral flagella, PFL (blue); ventral disc microtubules, MT (white); microribbons, MR (green); dense bands, DB; supernumerary microtubules, SMT (yellow). Margin-facing and axis-facing sides are shown for orientation. This volume is about ∼11 µm3 of the entire disc, which has a volume of ∼54 µm3. Scale bar, 500 nm.
Model of tomographic reconstruction of a Giardia trophozoite. The model was generated using IMOD [56]. The movie starts with the viewer looking torward the ventral surface of the cell. Major cytoskeletal components are present: anterior flagella, AFL (purple); caudal flagella, CFL (cyan); posterior-lateral flagella, PFL (blue); ventral flagella, VFL (magenta); supernumerary microtubules, SMT (yellow); microribbons, MR (green); microtubules, MT (white); open ends are green spheres; closed (capped) ends are red spheres. The overlap zone and dorsal-ventral line are indicated. The movie ends with the viewer looking torward the dorsal surface of the cell. Scale bar, 500 nm.
1.
Schwartz CL, Heumann JM, Dawson SC, Hoenger A (2012) A Detailed, Hierarchical Study of Giardia lamblia's Ventral Disc Reveals Novel Microtubule-Associated Protein Complexes. PLoS ONE
7(9): e43783
doi:10.1371/journal.pone.0043783.
[DOI] [PMC free article] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.
Supplementary Materials
Figure S1
Cryo-electron tomography of ventral discs. A) Isolated cytoskeleton with the ventral disc (VD) and all eight flagella (AFL, CFL, PFL, VFL) present. Areas suitable for cryo-tomography are over the hole in the carbon (box). B) A schematic representation of the ventral disc showing the location of each tomogram used in this study (1–5). Adapted with permission from [11]. C–G) Tomographic slices from each of the tilt-series used to generate the grand average (C, Tomo-1; D, Tomo-2; E, Tomo-3; F, Tomo-4; G, Tomo-5). The left panel is a 25 nm slice through the microtubules and the right panel is a 50 nm slice through the microribbons. Each tomogram is shown with its original orientation with the tilt-axis vertical. In all cases, the 8 nm repeat on the microtubule is obvious (arrow in F, left panel), but the crossbridges between adjacent microribbons are only sometimes seen clearly (arrow in F, right panel). Plus-end and margin directions are indicated. Scale bars in A = 2 µm, C–G = 100 nm.
Whole-cell reconstruction of an attached Giardia intestinalis trophozoite using 3View®. Each slice was obtained using a microtome inside a scanning electron microscope. After each section was removed, a backscatter-signal scanning electron micrograph was recorded [18]. IMOD [56] was used to model important features of the cytoskeleton and attachment sites. Each slice is 70 nm. The majority of organelles are visible with this method: Plasma membrane (grey), median body (orange), nuclei (brown), ventral disc (green), anterior flagella (purple), caudal flagella (cyan), posterior-lateral flagella (blue), and ventral flagella (magenta). Near the ventral portion of the cell, important components of attachment are seen (bare area, lateral crest, lateral shield). Scale bar, 2 µm.
Whole-cell reconstruction model showing relationships between cytoskeletal elements. The Video starts with the raw data, then transitions into the modeled data created by IMOD [56]. The ventral portion of the cell contains most of the cytoskeletal elements—the ventral disc (VD), median body (MB), and 4 pairs of flagella (anterior flagella, AFL; caudal flagella, CFL; posterior-lateral flagella, PFL; ventral flagella, VFL) as well as the two nuclei (N). The bulk of the cytoskeletal elements are at the ventral portion of the cell–the attachment site to the host microvili. Scale bar, 2 µm.
Tomographic reconstruction of 3 serial-montaged sections of a Giardia trophozoite. Each slice is 3 nm in the Z-plane. The transition zone between sections looks like a jump. Anterior flagella, AFL (purple); caudal flagella, CFL (cyan); posterior-lateral flagella, PFL (blue); ventral disc microtubules, MT (white); microribbons, MR (green); dense bands, DB; supernumerary microtubules, SMT (yellow). Margin-facing and axis-facing sides are shown for orientation. This volume is about ∼11 µm3 of the entire disc, which has a volume of ∼54 µm3. Scale bar, 500 nm.
Model of tomographic reconstruction of a Giardia trophozoite. The model was generated using IMOD [56]. The movie starts with the viewer looking torward the ventral surface of the cell. Major cytoskeletal components are present: anterior flagella, AFL (purple); caudal flagella, CFL (cyan); posterior-lateral flagella, PFL (blue); ventral flagella, VFL (magenta); supernumerary microtubules, SMT (yellow); microribbons, MR (green); microtubules, MT (white); open ends are green spheres; closed (capped) ends are red spheres. The overlap zone and dorsal-ventral line are indicated. The movie ends with the viewer looking torward the dorsal surface of the cell. Scale bar, 500 nm.