Organization of the cytoskeleton in the coenocytic algaVaucheria longicaulis var.macounii: an experimental study

Peat, L.; Oliveira, Luis

doi:10.1007/bf01378984

Cited by 13 publications

(4 citation statements)

References 54 publications

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“…These dots have not been documented in whole mount preparations of any filamentous fungus. When appearing as isolated structures, these dots were similar to those observed in vegetative algal cells (Peat & Oliveira, 1994). The anti-tubulin binding pattern in these algal cells was found to shift upon cold shock from a typical microtubular array to fluorescent, punctate dots.…”

Section: Discussionsupporting

confidence: 61%

Immunolocalization of tubulin and actin in thick‐sectioned fungal hyphae after freeze‐substitution fixation and methacrylate de‐embedment

Czymmek

Bourett

Howard

1996

Journal of Microscopy

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Immunolocalizations in whole mounts of walled cells require an empirically derived, species‐specific permeabilization strategy. Particularly when cell walls are recalcitrant to enzymatic digestion, as with many fungi, permeabilization can degrade structure and reduce or destroy antigenicity. To avoid these potential problems, hyphae were freeze‐substituted, embedded in a methacrylate resin, thick‐sectioned and de‐embedded prior to immunolocalization. The cytoskeletal proteins actin and β‐tubulin were labelled via indirect immunofluorescence in hyphal tip cells of Magnaporthe grisea, and Trichoderma viride. Well‐defined punctate actin plaques were observed concentrated at the subapical cell periphery in both species, especially near the hypha–substratum interface. In addition, a Spitzenkörper core and less intense cytoplasmic binding were observed. Immunoelectron microscopy confirmed localization of actin in the Spitzenkörper core and filasomes. β‐Tubulin was immunolocalized as both linear arrays and punctate dots via epifluorescence microscopy. Analysis of 450–550‐nm‐thick serial sections contributed to improved resolution by the reduction of out‐of‐focus blur. Overall, the freeze substitution methacrylate de‐embedment technique provided superior preservation, serial section analysis, and improved antibody penetration and resolution of these cytoskeletal proteins. The technique will be a valuable tool for use with a variety of reporter molecules in cells of fungi.

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Section: Discussionsupporting

confidence: 61%

Immunolocalization of tubulin and actin in thick‐sectioned fungal hyphae after freeze‐substitution fixation and methacrylate de‐embedment

Czymmek

Bourett

Howard

1996

Journal of Microscopy

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“…Actin dynamics in M. denticulata are disturbed by a breakdown of an actin filament network and not by an abnormal aggregation of actin filaments as reported from cytochalasin action in pollen tubes (Lancelle and Hepler 1988). Similar disruption, fragmentation, and disorganization of actin filaments by cytochalasins (Hush andOverall 1992, Peat andOliveira 1994) and latrunculins (Ayscough et al 1997, Bachewich andHeath 1998) are known from various plant cells (for summary and discussion, see, e.g., McCurdy etal. 1991).…”

Section: Discussionmentioning

confidence: 91%

Changes of the actin filament system in the green algaMicrasterias denticulata induced by different cytoskeleton inhibitors

et al. 2000

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Summary. Two different techniques have been adapted for Micras-terias denticulata to depict the actin cytoskeleton of both untreated and inhibitor-treated developing cells: the "quickstaining method", where the cells are fixed in a mixture of glutaraldehyde and formaldehyde followed by staining with phalloidin without embedding, and the "methacrylate method", where the cells are also fixed by aldehydes and where the embedding medium is removed prior to incubation with an actin antibody. Both methods produce sufficient preservation and visualization of actin microfilaments (MFs) and confirm earlier observations on the presence of a cortical actin MF network in both the growing and the nongrowing semicell as well as of a basketlike MF arrangement around the migrating nucleus. The results show that a network of actin MFs is essential for the proper development of the young lobes of M. denticulata. Early developmental stages expanding uniformly at the beginning of growth lack any netlike actin MF arrangement. The actin cytoskeleton in developing cells treated with the actin-targeting agents cytocbalasin D and latrunculin B is markedly influenced. Cytochalasin D, which produces the most pronounced effects, causes a breakdown of the network of actin MFs, resulting in bright actin clusters as well as in short and abnormally thick actin fragments particularly in cortical cell regions. In latrunculin B-treated cells remnants of the former actin MF network are still visible, yet most of the actin cytoskeleton appears collapsed and is reduced to short filament pieces. The disturbance of the actin MF system visualized in the present study correlates with the severe morphological and ultrastructural changes occurring in desmid cells as a consequence of both drugs. The dinitroanilin herbicide oryzalin, known to deploymerize cytoplasmic microtubules, causes also an impairment of the actin cytoskeleton in M. denticulata though not sufficient to influence normal cell growth and differentiation.

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“…tentatively defined similar structures in Vaucheria sessilis (Vaucher) De Candolle as microfilaments. Microfilaments have a similar distribution to that of cytoplasmic tracks (Peat & Oliveira, 1993 a). The movement of most organelles in Vaucheria longicaulis was proposed to occur along MAR elements, possibly through their association with actin filaments (Ott, 1992).…”

Section: Discussionmentioning

confidence: 99%

Wound‐healing in Vaucheria longicaulis Hoppaugh var. macounii Blum.

Tornbom

Oliveira

1993

New Phytologist

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SUMMARYDifferential interference contrast microscopy of the cytoplasm of Vaucheria longicaulis Hoppaugh var. macounii Blum reveals the presence of cable-like strands (tracks). The cytoplasmic tracks are orientated parallel to the length of the filament, and the organelles are closely associated and appear to move along them. Nuclei, mitochondria and Rhodamine B-positive bodies (RBIs) interact with a single track. Chloroplasts are closely associated with several tracks, although preferential association with one of the tracks is clearly observed. In uncut filaments, the different classes of organelles move independently of one another and travel at different speeds. Chloroplasts, mitochondria, RBIs, and smaller inclusions (SSIs) exhibit a bulk pattern of motion characterized by brief reversals in their primary pattern of movement that do not affect their final direction of travel. Nuclei move independently of each other and do not reverse their direction of movement. In cut filaments, cytoplasmic track density and relationship to organelles in the wound region during stage 1 is similar to that in uncut filaments. The cytoplasmic tracks extend into the wound-healing vesicle cytoplasm. Mitochondria and similarly-sized organelles move rapidly (in bulk) toward the wound site and into the wound-healing vesicle. In stage 2, an increase in cytoplasmic track density is observed in the wound region, and bulk movement of mitochondria and RBIs occurs toward the wound site. Nuclei also move in bulk, unidirectionally toward the wound. Organelle retraction from the wound is restricted to the chloroplasts.Both uncut and cut filaments were treated with the cytoskeleton depolymerizers Cytochalasin B and Oryzalin to determine the role(s) of microfilaments and microtubules respectively in organelle movement and the overall role of the cytoskeleton in the wound-healing process. In uncut filaments, cytoplasmic streaming is severely reduced by both Cytochalasin B and Oryzalin, with the greatest reduction observed following cytochalasin B treatment. In cut filaments Cytochalasin B shows a greater effect on chloroplasts, mitochondria, and RBIs behaviour, while Oryzalin preferentially affects the nuclei. The results indicate that the bulk movement of chloroplasts, mitochondria and RBIs in uncut filaments may be microfilament-based, and the movement of nuclei microtubule-based.

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Organization of the cytoskeleton in the coenocytic algaVaucheria longicaulis var.macounii: an experimental study

Cited by 13 publications

References 54 publications

Immunolocalization of tubulin and actin in thick‐sectioned fungal hyphae after freeze‐substitution fixation and methacrylate de‐embedment

Immunolocalization of tubulin and actin in thick‐sectioned fungal hyphae after freeze‐substitution fixation and methacrylate de‐embedment

Changes of the actin filament system in the green algaMicrasterias denticulata induced by different cytoskeleton inhibitors

Wound‐healing in Vaucheria longicaulis Hoppaugh var. macounii Blum.

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