The flagellar apparatus and cytoskeleton of the dinoflagellates

Roberts, Keith; Roberts, Julia E.

doi:10.1007/bf01320818

Cited by 58 publications

(43 citation statements)

References 68 publications

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“…1A, 1C, and 1D). Consistent with previous observations from the motile stage of the dinoflagellate Gymnodinum sanguineum (Roberts and Roberts 1991), no extensive interweaved fine filaments were observed. Instead, we observed regularly spaced bundles forming a lattice-like structure, suggesting an orthogonal organization.…”

Section: Discussionsupporting

confidence: 93%

“…Even though actin is known to exist in these organisms (Watanabe et al 2006), the observation of this structure in Symbiodinium cells has not been documented. At most, there are only a couple of reports on its visualization as a scarce net of filaments by fluorescent phalloidin in cells at the motile stage of Gymnodinium sanguineum (Roberts and Roberts 1991;Roberts et al 1992). In this work, we report the visualization of the actin cytoskeleton as a highly organized reticular network in cultured Symbiodinium kawagutii cells from fixed and freeze-fractured cells.…”

Section: Introductionmentioning

confidence: 95%

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The actin cytoskeleton organization and disorganization properties of the photosynthetic dinoflagellateSymbiodinium kawagutiiin culture

2014

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The actin cytoskeleton organization in symbiotic marine dinoflagellates is largely undescribed; most likely, due to their intense pigment autofluorescence and cell walls that block fluorescent probe access. Using a freeze-fracture and fixation procedure, we observed the actin cytoskeleton of Symbiodinium kawagutii cultured in vitro with fluorescently labeled phalloidin and by indirect immunofluorescence with monoclonal antibodies specific for actin. The cytoskeleton appeared as an organized network with interconnected cortical and cytoplasmic thick filaments, along with some intertwined fine filaments. It showed a grid-type, reticular pattern organized in a lattice-like structure within the cell and throughout the cytoplasm. This organization was similar when the observations were done with either fluorescein isothiocyanate (FITC)-phalloidin or anti-actin, although the latter showed a more evenly distributed fluorescence characteristic of nonpolymerized actin. The network organization collapsed upon treatment with latrunculin, resulting in bright foci and diffuse fluorescence. A similar effect was obtained upon butanedione monoxime treatment, except that no bright foci were observed. We have been able to successfully visualize the actin cytoskeleton of S. kawagutii cells using fluorescence-based procedures. This is the first report on the visualization of the organization of the actin cytoskeleton under various conditions in these walled, highly autofluorescent cells.

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Section: Discussionsupporting

confidence: 93%

Section: Introductionmentioning

confidence: 95%

The actin cytoskeleton organization and disorganization properties of the photosynthetic dinoflagellateSymbiodinium kawagutiiin culture

2014

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“…Centrin-containing fibers have been found in other excavate groups, such as trichomonads (10), retortamonads (39), and diplomonads (6), and other flagellates, including the chrysomonads (11), the dinoflagellates (27), and Chlamydomonas (38), but this in itself is not strong evidence for the existence of bilobe homologs. At this point, taxonomic sampling is too widespread and infrequent to make any reasonable inferences regarding the evolution of a morphologically and biochemically complex structure.…”

Section: Discussionmentioning

confidence: 99%

Morphology of the Trypanosome Bilobe, a Novel Cytoskeletal Structure

et al. 2012

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The trypanosome bilobe is a cytoskeletal structure of unclear function. To date, four proteins have been shown to localize stably to it: TbMORN1, TbLRRP1, TbCentrin2, and TbCentrin4. In this study, a combination of immunofluorescence microscopy and electron microscopy was used to explore the morphology of the bilobe and its relationship to other nearby cytoskeletal structures in the African trypanosome procyclic trypomastigote. The use of detergent/salt-extracted flagellum preparations was found to be an effective way of discerning features of the cytoskeletal ultrastructure that are normally obscured. TbMORN1 and TbCentrin4 together define a hairpin structure comprising an arm of TbCentrin4 and a fishhook of TbMORN1. The two arms flank a specialized microtubule quartet and the flagellum attachment zone filament, with TbMORN1 running alongside the former and TbCentrin4 alongside the latter. The hooked part of TbMORN1 sits atop the flagellar pocket collar marked by TbBILBO1. The TbMORN1 bilobe occasionally exhibits tendrillar extensions that seem to be connected to the basal and probasal bodies. The TbMORN1 molecules present on these tendrils undergo higher rates of turnover than those for molecules on the main bilobe structure. These observations have been integrated with previous detailed descriptions of the cytoskeletal elements in trypanosome cells.

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“…histone-containing) dinoflagellates. It also has scales (Clarke & Pennick, 1976), an unusual cytoskeleton (Höhfeld & Melkonian, 1998) and a flagellar root system (Roberts, 1985(Roberts, , 1991 that, although reminiscent of and clearly related to those of dinoflagellates, also present important differences. Whether these differences were already present in the common ancestor of Oxyrrhis and the dinoflagellates or they arose in the Oxyrrhis lineage is still unclear.…”

Section: Conclusion -The Early Evolution Of Dinoflagellates and Apicmentioning

confidence: 99%

Multiple protein phylogenies show that Oxyrrhis marina and Perkinsus marinus are early branches of the dinoflagellate lineage

Saldarriaga

McEWAN

Fast

et al. 2003

International Journal of Systematic and Evolutionary Microbiology

182

146

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Oxyrrhis marina and Perkinsus marinus are two alveolate species of key taxonomic position with respect to the divergence of apicomplexans and dinoflagellates. New sequences from Oxyrrhis, Perkinsus and a number of dinoflagellates were added to datasets of small-subunit (SSU) rRNA, actin, a-tubulin and b-tubulin sequences, as well as to a combined dataset of all three proteincoding genes, and phylogenetic trees were inferred. The parasitic Perkinsus marinus branches at the base of the dinoflagellate clade with high support in most of the individual gene trees and in the combined analysis, strongly confirming the position originally suggested in previous SSU rRNA and actin phylogenies. The SSU rRNA from Oxyrrhis marina is extremely divergent, and it typically branches with members of the Gonyaulacales, a dinoflagellate order where SSU rRNA sequences are also divergent. Conversely, none of the three protein-coding genes of Oxyrrhis is noticeably divergent and, in trees based on all three proteins individually and in combination, Oxyrrhis branches at the base of the dinoflagellate clade, typically with high bootstrap support. In some trees, Oxyrrhis and Perkinsus are sisters, but most analyses indicate that Perkinsus diverged prior to Oxyrrhis. Morphological characters have previously pointed to Oxyrrhis as an early branch in the dinoflagellate lineage; our data support this suggestion and significantly bolster the molecular data that support a relationship between Perkinsus and dinoflagellates. Together, these two organisms can be instrumental in reconstructing the early evolution of dinoflagellates and apicomplexans by helping to reveal aspects of the ancestors of both groups.

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The flagellar apparatus and cytoskeleton of the dinoflagellates

Cited by 58 publications

References 68 publications

The actin cytoskeleton organization and disorganization properties of the photosynthetic dinoflagellateSymbiodinium kawagutiiin culture

The actin cytoskeleton organization and disorganization properties of the photosynthetic dinoflagellateSymbiodinium kawagutiiin culture

Morphology of the Trypanosome Bilobe, a Novel Cytoskeletal Structure

Multiple protein phylogenies show that Oxyrrhis marina and Perkinsus marinus are early branches of the dinoflagellate lineage

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