Motile Tubular Vacuole Systems

Ashford, A. E.; Allaway, W. G.

doi:10.1007/978-3-540-70618-2_2

Cited by 15 publications

(12 citation statements)

References 334 publications

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“…However, the vacuolar system in living filamentous fungi has been revealed as a complex tubular system, not a simple spherical form (Shepherd et al 1993;Rees et al 1994;Uetake et al 2002;Shoji et al 2006;Ashford and Allaway 2007). The vacuoles of ectomycorrhizal (EM) fungi are motile and consist of tubular and spherical forms (Shepherd et al 1993;Cole et al 1998).…”

Section: Introductionmentioning

confidence: 99%

pH measurement of tubular vacuoles of an arbuscular mycorrhizal fungus, Gigaspora margarita

et al. 2014

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Section: Introductionmentioning

confidence: 99%

pH measurement of tubular vacuoles of an arbuscular mycorrhizal fungus, Gigaspora margarita

et al. 2014

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“…It is well established that the vacuole serves as a storage compartment for (poly)phosphate (1,2) and nitrogen (N), particularly as N-rich amino acids (19), and as these compounds are also extensively translocated in both mycorrhizal and saprotrophic fungi (3,5), it has been proposed that the vacuole system may be directly involved in their longitudinal movement (1,3). Vacuolar organization is unique in the filamentous fungi, with all species so far examined possessing a highly dynamic pleiomorphic tubular vacuolar system (1,2,6,16,25,28,32,33,36).…”

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confidence: 99%

“…Vacuolar organization is unique in the filamentous fungi, with all species so far examined possessing a highly dynamic pleiomorphic tubular vacuolar system (1,2,6,16,25,28,32,33,36). While superficially similar reticulate vacuolar networks appear during normal vacuole ontogeny in yeasts (39) and plants (e.g., see reference 20) or in specialized cells such as pollen tubes (14), only in the filamentous fungi does the vacuole form a constitutive, physically contiguous, extended organelle spanning several cell (septal) compartments over a considerable physical distance.…”

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confidence: 99%

“…While superficially similar reticulate vacuolar networks appear during normal vacuole ontogeny in yeasts (39) and plants (e.g., see reference 20) or in specialized cells such as pollen tubes (14), only in the filamentous fungi does the vacuole form a constitutive, physically contiguous, extended organelle spanning several cell (septal) compartments over a considerable physical distance. If this vacuole supported transport, it would provide an internal compartment, separate from the cytoplasm, with high concentrations of solutes and would contribute to bidirectional solute movement (2). However, despite the unique nature and considerable potential importance of such an intracellular transport system to filamentous fungi, to date there has been no direct experimental test of either the mechanism or the rate of transport that such a vacuole system could support.…”

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The Vacuole System Is a Significant Intracellular Pathway for Longitudinal Solute Transport in Basidiomycete Fungi

et al. 2006

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Mycelial fungi have a growth form which is unique among multicellular organisms. The data presented here suggest that they have developed a unique solution to internal solute translocation involving a complex, extended vacuole. In all filamentous fungi examined, this extended vacuole forms an interconnected network, dynamically linked by tubules, which has been hypothesized to act as an internal distribution system. We have tested this hypothesis directly by quantifying solute movement within the organelle by photobleaching a fluorescent vacuolar marker. Predictive simulation models were then used to determine the transport characteristics over extended length scales. This modeling showed that the vacuolar organelle forms a functionally important, bidirectional diffusive transport pathway over distances of millimeters to centimeters. Flux through the pathway is regulated by the dynamic tubular connections involving homotypic fusion and fission. There is also a strongly predicted interaction among vacuolar organization, predicted diffusion transport distances, and the architecture of the branching colony margin.Mycelial fungi have a growth form which is unique among multicellular organisms and which maintains a highly polarized internal cellular organization to support tip extension. Saprotrophic fungi are particularly adept at foraging for resources, often over inert substrates. This demands a bidirectional internal transport system to provide the tip with sufficient nutrients to maintain growth and to return newly discovered resources to the parent colony. However, despite the central importance of nutrient translocation to fungal growth, the mechanism(s) that drives transport and the identity of the transport pathway(s) are not known (5).It is well established that the vacuole serves as a storage compartment for (poly)phosphate (1, 2) and nitrogen (N), particularly as N-rich amino acids (19), and as these compounds are also extensively translocated in both mycorrhizal and saprotrophic fungi (3, 5), it has been proposed that the vacuole system may be directly involved in their longitudinal movement (1, 3). Vacuolar organization is unique in the filamentous fungi, with all species so far examined possessing a highly dynamic pleiomorphic tubular vacuolar system (1,2,6,16,25,28,32,33,36). While superficially similar reticulate vacuolar networks appear during normal vacuole ontogeny in yeasts (39) and plants (e.g., see reference 20) or in specialized cells such as pollen tubes (14), only in the filamentous fungi does the vacuole form a constitutive, physically contiguous, extended organelle spanning several cell (septal) compartments over a considerable physical distance. If this vacuole supported transport, it would provide an internal compartment, separate from the cytoplasm, with high concentrations of solutes and would contribute to bidirectional solute movement (2). However, despite the unique nature and considerable potential importance of such an intracellular transport system to filamentous fungi, to date t...

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“…Phosphorus localization at the ultrastructural level has been investigated intensively by EDXS in ectomycorrhizal fungi, which are symbiotic organisms with plant roots that contribute to the improvement of plant nutrition (3,4,20). Formerly, on the basis of EDXS (6) and TBO staining (5), the polyP of ectomycorrhizal fungi was thought to be present as precipitated granules in vacuoles.…”

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Direct Labeling of Polyphosphate at the Ultrastructural Level inSaccharomyces cerevisiaeby Using the Affinity of the Polyphosphate Binding Domain ofEscherichia coliExopolyphosphatase

Saito

Ohtomo

Kuga-Uetake

et al. 2005

Appl Environ Microbiol

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Inorganic polyphosphate (polyP) is a linear polymer of orthophosphate and has many biological functions in prokaryotic and eukaryotic organisms. To investigate polyP localization, we developed a novel technique using the affinity of the recombinant polyphosphate binding domain (PPBD) of Escherichia coli exopolyphosphatase to polyP. An epitope-tagged PPBD was expressed and purified from E. coli. Equilibrium binding assay of PPBD revealed its high affinity for long-chain polyP and its weak affinity for short-chain polyP and nucleic acids. To directly demonstrate polyP localization in Saccharomyces cerevisiae on resin sections prepared by rapid freezing and freeze-substitution, specimens were labeled with PPBD containing an epitope tag and then the epitope tag was detected by an indirect immunocytochemical method. A goat anti-mouse immunoglobulin G antibody conjugated with Alexa 488 for laser confocal microscopy or with colloidal gold for transmission electron microscopy was used. When the S. cerevisiae was cultured in yeast extract-peptone-dextrose medium (10 mM phosphate) for 10 h, polyP was distributed in a dispersed fashion in vacuoles in successfully cryofixed cells. A few polyP signals of the labeling were sometimes observed in cytosol around vacuoles with electron microscopy. Under our experimental conditions, polyP granules were not observed. Therefore, it remains unclear whether the method can detect the granule form. The method directly demonstrated the localization of polyP at the electron microscopic level for the first time and enabled the visualization of polyP localization with much higher specificity and resolution than with other conventional methods.Inorganic polyphosphate (polyP) is a linear polymer of orthophosphate (P i ) connected by high-energy bonds. PolyP occurs in a wide range of organisms, including prokaryotes and eukaryotes. PolyP has various biological functions; for example, it acts as a P i reservoir, as an alternative source of highenergy bonds, and as a buffer against alkaline conditions and metals (25). Furthermore, polyP also has regulatory functions such as competence for transformation (18), motility (36, 37), gene expression under stressed conditions (24,35,46), and protein degradation in amino acid starvation (28, 29) in prokaryotic organisms. The regulatory functions of polyP in eukaryotes are less clear, but some important facts are known. Recently, involvement of polyP in apoptosis (43) and enhancement of the mitogenic activities of acidic and basic fibroblast growth factors by polyP (45) have been suggested to occur in mammalian cells.The presence of polyP in cells can be visualized by staining with toluidine blue O (TBO) or 4Ј,6-diamidino-2-phenylindole (DAPI). DAPI is usually used for DNA detection, because blue fluorescence is apparent when the stained tissues are viewed under UV light. However, DAPI-polyP fluoresces yellow at high concentrations when viewed under UV (48). These staining methods have often been used for detecting polyPaccumulating bacteria in activated...

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Motile Tubular Vacuole Systems

Cited by 15 publications

References 334 publications

pH measurement of tubular vacuoles of an arbuscular mycorrhizal fungus, Gigaspora margarita

pH measurement of tubular vacuoles of an arbuscular mycorrhizal fungus, Gigaspora margarita

The Vacuole System Is a Significant Intracellular Pathway for Longitudinal Solute Transport in Basidiomycete Fungi

Direct Labeling of Polyphosphate at the Ultrastructural Level inSaccharomyces cerevisiaeby Using the Affinity of the Polyphosphate Binding Domain ofEscherichia coliExopolyphosphatase

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