Calcium involvement in dimorphism of Ophiostoma ulmi, the Dutch elm disease fungus, and characterization of calcium uptake by yeast cells and germ tubes

Gadd, Geoffrey M.; Brunton, A. H.

doi:10.1099/00221287-138-8-1561

Cited by 27 publications

(12 citation statements)

References 65 publications

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“…Only those phosphorylations coCytoplasmic Ca2+ has emerged as an intracellular regulator of central importance in transducing external stimuli in animals (Berridge, 1987) and more recently in plants (Knight et al, 1991). Although the evidence for a second messenger function for Ca2+ in fungi is mounting and a r6le for the ion in morphogenesis is established (Elliott, 1986;Pitt & Kaile, 1990;Brunton & Gadd, 1991;Gadd & Brunton, 1992) measurements of [Ca"], remain difficult in these organisms owing to the small size and vacuolate nature of cells. Technical problems relating to permeability also prevail which limit the value in fungi of fluorescent Ca2+ chelating dyes which were designed essentially for use with animal systems (Tsien et al, 1982) and which can themselves perturb [Ca2+], under certain conditions (Rink & Pozzan, 1985).…”

Section: Two-dimensional Sds-page Analysis Of P Hosp Hop R O Teins Dumentioning

confidence: 99%

“…C. Barnes regulating calcium-stimulated reproduction is now indicated in Phytophthora (Elliott, 1986) and P. notatum (Pitt & Kaile, 1990). A r6le for calmodulin-mediated protein kinase C and calcium in yeast-mycelium transition of Ophiostoma ulmi has been proposed (Brunton & Gadd, 1991 ;Gadd & Brunton, 1992).…”

Section: [Bis(carboxymethyl)amino]-5-methyl-phenoxy]-methyl]-6-methoxmentioning

confidence: 99%

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Calcium homeostasis, signalling and protein phosphorylation during calcium-induced conidiation in Penicillium notatum

Pitt

Barnes²

1993

Journal of General Microbiology

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~ ~~~~~~Cytosolic free calcium concentration [Ca2+], of protoplasts from Penicillium notatum was measured using the permeant acetoxy ester (quin-2-AM) of the calcium-chelating fluorescent dye quin-2. Low uptake of the ester occurred at pH 5.8-7.0 and its subsequent hydrolysis was low. Uptake was promoted by an external pH of 5.0 and significant hydrolysis to quin-2 achieved by adjustment of the internal pH to 7.2, which was near the optimum of the carboxylic esterases responsible for the hydrolysis. Uptake of Ca2+ was biphasic with the average cell calcium concentration of protoplasts increasing from an initial value of 2 pmol to 50 pmol (kg cell water)-', during attainment of the steady state after 30 min, at which time [Ca2+], was unchanged at 20 nM but increased to 182 nM at 2-6 h exposure to 2.5 mM-Ca2+. Broadly similar changes in [Ca2+], were found in protoplasts derived from mycelium samples exposed to Ca2+ over the same period of time. The location of Ca2+ was determined in subfractionated organelles and characterized using enzyme markers and electron microscopy. In 32 h mycelium preloaded with Ca2+ for 6 h, Ca2+ was located principally in the mitochondria with lower concentrations associated with the endoplasmic reticulum, Golgi, vacuoles and plasma membrane components. Calcium was not released by inositol 1,4,5-trisphosphate or the calcium ionophore A23187 from any subcellular fractions obtained from mycelium on Percoll gradients, nor from preparations of vacuoles or plasmalemma vesicles, except in the case of mitochondria where rapid release of the ion was achieved by the addition of 2-5 p~-A23187. The anti-calmodulin agent calmidazolium (R24571) greatly reduced sporulation when addition preceded that of Ca2+. Calcium-induced cultures showed massive novel protein phosphorylation 2 h after addition of the ion which was virtually eliminated by R24571, whilst 1 h and 4-6 h protein phosphorylations, which were also present to some degree in vegetative controls, were substantially reduced. Two-dimensional SDS-PAGE analysis of phosphoproteins confirmed that Ca2+-induced mycelium had enhanced capacity for calmodulin-mediated phosphorylation relative to corresponding vegetative cells and that complex differential changes in such phosphorylations occurred during Ca2+-induction of the sporulation process.

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Section: Two-dimensional Sds-page Analysis Of P Hosp Hop R O Teins Dumentioning

confidence: 99%

Section: [Bis(carboxymethyl)amino]-5-methyl-phenoxy]-methyl]-6-methoxmentioning

confidence: 99%

Calcium homeostasis, signalling and protein phosphorylation during calcium-induced conidiation in Penicillium notatum

Pitt

Barnes²

1993

Journal of General Microbiology

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“…A good example is provided by calcium, an important intracellular second messenger in fungal growth and differentiation, which can also be highly toxic within cells owing to precipitation of phosphates. Fungi, like other eukaryotic cells, maintain cytosolic free [Ca^^] at around 0-1 //M by means of a variety of transport systems located on the plasma and vacuolar membranes which effect influx/efflux and vacuolar compartmentation; cytosolic free [Ca"^] may also be modulated by interaction with calcium-binding proteins (Miller, Vogg & Sanders, 1990;Gadd & Brunton, 1992).…”

Section: Metalsmentioning

confidence: 99%

Interactions of fungi with toxic metals

1993

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SUMMARY This review details the major interactions of fungi with toxic metal species. Physico‐chemical and biological aspects are discussed including definitions and classification of metals in biological contexts, mechanisms of metal fungitoxicity, resistance and tolerance, environmental influences and the occurrence of fungi in metal‐polluted habitats. Cellular interactions include extracellular precipitation and complexation, binding to cell walls, transport of monovalent and divalent metal cations, intracellular fates of toxic metal species (including metal‐binding proteins and peptides, and vacuolar compartmentation), and metal transformations including organometal(loid) synthesis. Significant interactions between metals and mycorrhizal fungi and macrofungi are summarized with reference to the amelioration of plant phytotoxicity and metal accumulation respectively. Biotechnological aspects of metal‐fungal interactions relate to the biological treatment of metal‐contaminated effluents and waste streams for metal removal/recovery and environmental protection.

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“…It participates in multiple regulatory functions including sporulation, ramification, tip growth and hyphae reorientation, direction of localized stimuli, bud germination, regulation of dimorphism, sexual reproduction and control of the cell cycle has been described (23). At high concentration, calcium is toxic; for this reason, cells utilize a complex homeostatic system to maintain low levels of calcium concentration (6). Pera and Callieri (18), verified that the addition of 0.5 g/L of CaCl2 to the culture medium, promoted an increase in mycelium ramification in the filamentous strain of A. niger.…”

Section: Discussionmentioning

confidence: 99%

“…Calcium is an important element for growth, metabolism and differentiation of several fungi and yeasts (6,23). It participates in multiple regulatory functions including sporulation, ramification, tip growth and hyphae reorientation, direction of localized stimuli, bud germination, regulation of dimorphism, sexual reproduction and control of the cell cycle has been described (23).…”

Section: Discussionmentioning

confidence: 99%

Reversion by calcium of a yeast-like development to the original filamentous form, of the 10V10 5-fluorocytosine-sensitive mutant of Aspergillus niger

Goulart¹,

Marin

2005

Braz. J. Microbiol.

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Some filamentous fungi present the phenomenon of dimorphism, their morphological structure alterations being capable of inducing metabolism changes. The Aspergillus niger strain 10v10, a producer of citric acid, was submitted to the mutagenic action of ultraviolet irradiation which respectively selects mutants sensitive or resistant to the antifungi agent 5 fluorocytosine (5-FC). 5-FC sensitive mutants presented a morphological alteration to a yeast-like form. The effects of pH changes, addition of salts (KH 2 PO 4 , NH 4 NO 3 , MgSO4 and MgCl2), the presence of osmotic stabilizers, as well as of calcium chloride, on morphological reversal and acid production were studied. Morphological reversal to the filamentous form was observed only in the presence of CaCl 2 (500mM) for the mutants strains 1 and 2, while the acid production occurred in both, yeast-like and filamentous forms.

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Calcium involvement in dimorphism of Ophiostoma ulmi, the Dutch elm disease fungus, and characterization of calcium uptake by yeast cells and germ tubes

Cited by 27 publications

References 65 publications

Calcium homeostasis, signalling and protein phosphorylation during calcium-induced conidiation in Penicillium notatum

Calcium homeostasis, signalling and protein phosphorylation during calcium-induced conidiation in Penicillium notatum

Interactions of fungi with toxic metals

Reversion by calcium of a yeast-like development to the original filamentous form, of the 10V10 5-fluorocytosine-sensitive mutant of Aspergillus niger

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