Calcium in fungi

Pitt, D.; Ugalde, Unai

doi:10.1111/j.1365-3040.1984.tb01437.x

Cited by 63 publications

(28 citation statements)

References 86 publications

(72 reference statements)

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“…The present investigation showed that exogenous Ca 2+ ion stimulated spore gemination, hyphal extension, branching and sexual reproduction in D. uninucleata, similar results were reported for other fungi (Pitt and Ugalde, 1984;Schmid and Harold, 1988). concentrations from 1-10 mM Ca 2+ increased the rate of spore germination and produced synchronus cultures.…”

Section: Discussionsupporting

confidence: 90%

Calcium and Dipodascopsis uninucleata

Elwy¹

1999

Pakistan J. of Biological Sciences

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Growth rate and branching of D. uninucleata were correlated to the exocellular concentration of calcium in culture medium. Calcium concentrations of 1-10 mM stimulated germ tube formation and reduced the lag phase. Mycelia grew in media amended with 1-0 mM Ca 2+ were highly branched and the number of cells/hypha together with the number of cells/branch significantly increased. Gametangial formation have been induced by 10-40 mM Ca 2+ and the highest percent of ascus formation with the longest asci was achieved in the presence of 10 mM calcium. Increasing Ca 2+ ions concentration above 40 mM had no further effect on growth aspects yet concentrations higher than 160 mM were toxic and partially inhibited growth, branching and reproduction.

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Section: Discussionsupporting

confidence: 90%

Calcium and Dipodascopsis uninucleata

Elwy¹

1999

Pakistan J. of Biological Sciences

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“…Calcium uptake was expressed on a cell water basis by the relationship 2.54 liter of cell water per kg (dry weight) (29). Provided that normalization is performed on the basis of cell volume (rather than surface area), previous measurements have shown that transport rates of both primary (H+ translocating) and secondary (nutrient translocating) systems measured in mycelial and shaking culture cells are in good agreement (30)(31)(32) For Ca2+ efflux via H+/Ca2+ antiport, the minimum required stoichiometry (H+/Ca2+ = n) is given by the free energy relationship [3] where ASH+ is F-pmf (proton-motive force) (units, Ukmold). (36), ASH+ at pHO 8.4 is -13.7 kJ mol1.…”

Section: Methodsmentioning

confidence: 89%

“…Cytosolic free calcium ([Ca2+]c) plays a central role in signal transduction in animal and plant cells (1,2 A large body of evidence indicates that nutritional and developmental responses of fungi to environmental stimuli are similarly mediated by [Ca2+]c (3). For example, Ca2+ ionophores induce branching in Achlya and Neurospora (4,5) in a manner suggesting that apical dominance is abolished (6);…”

mentioning

confidence: 99%

Cytosolic calcium homeostasis in fungi: roles of plasma membrane transport and intracellular sequestration of calcium.

Miller

Vogg

Sanders

1990

Proc. Natl. Acad. Sci. U.S.A.

100

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Cytosolic free calcium ([Ca2+]k) has been measured in the mycelial fungus Neurospora crassa with Ca2+-selective microelectrodes. The mean value of [Ca2+J is 92 ± 15 nM and it is insensitive to external pH values between 5.8 and 8.4. Simultaneous measurement of membrane potential enables the electrochemical potential difference for Ca2+ across the plasma membrane to be estimated as about -60 kJimol'-a value that cannot be sustained either by a simple Ca2+-ATPase, or, in alkaline conditions, by straightforward H+/Ca2+ exchange with a stoichiometric ratio of <5 H+/Ca2+. We propose that the most likely alternative mechanism of Ca2+ efflux is ATP-driven H+/Ca2+ exchange, with a stoichiometric ratio of at least 2 H+/Ca2 . In accord with this proposal, depletion of the ATP level from 2.5 to 0.5 mM by CN-elicits an increase in [Ca2+Jc, but only in alkaline conditions in which the putative H+/Ca2+-ATPase would be selectively stalled. The insensitivity of Ca2+ homeostasis to CN-in more acid conditions implies that the Km (ATP) of the transport system is 100 ,uM or less. The increase in [Ca2+1C in the presence of CN-at pH 8.4 (50 nM-min-') is compared with 45Ca2+ influx (0.62 mMniinif') under the same conditions. The proportion of entering Ca2+ remaining free in the cytosol is only 8 X 10-5, and since the concentration of available chelation sites on Ca2+-binding proteins is unlikely to exceed 100 ,uM, a major role for the fungal vacuole in short-term Ca2+ homeostasis is indicated. This notion is supported by the observation that cytosolic Ca2+ homeostasis is disrupted by a protonophore, which rapidly abolishes tbe driving force (a transmembrane pH difference) for Ca2+ uptake into fungal vacuoles.Cytosolic free calcium ([Ca2+]

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“…In order to keep this steep gradient, fungi have to efficiently regulate Ca 2+ . Ca 2+ can enter the cytoplasm both actively and passively, so Ca 2+ concentration in the cytoplasm is maintained at low levels by actively pumping it either out of the cell, or by sequestration in organelles (mitochondria, endoplasmic reticulum, and vacuoles), or by binding it onto cytoplasmic proteins (calmodulins) and within the cell wall [50,80,81].…”

Section: Fungi and Cacomentioning

confidence: 99%

Role of Fungi in the Biomineralization of Calcite

2016

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Abstract:In the field of microbial biomineralization, much of the scientific attention is focused on processes carried out by prokaryotes, in particular bacteria, even though fungi are also known to be involved in biogeochemical cycles in numerous ways. They are traditionally recognized as key players in organic matter recycling, as nutrient suppliers via mineral weathering, as well as large producers of organic acids such as oxalic acid for instance, an activity leading to the genesis of various metal complexes such as metal-oxalate. Their implications in the transformation of various mineral and metallic compounds has been widely acknowledged during the last decade, however, currently, their contribution to the genesis of a common biomineral, calcite, needs to be more thoroughly documented. Calcite is observed in many ecosystems and plays an essential role in the biogeochemical cycles of both carbon (C) and calcium (Ca). It may be physicochemical or biogenic in origin and numerous organisms have been recognized to control or induce its biomineralization. While fungi have often been suspected of being involved in this process in terrestrial environments, only scarce information supports this hypothesis in natural settings. As a result, calcite biomineralization by microbes is still largely attributed to bacteria at present. However, in some terrestrial environments there are particular calcitic habits that have been described as being fungal in origin. In addition to this, several studies dealing with axenic cultures of fungi have demonstrated the ability of fungi to produce calcite. Examples of fungal biomineralization range from induced to organomineralization processes. More examples of calcite biomineralization related to direct fungal activity, or at least to their presence, have been described within the last decade. However, the peculiar mechanisms leading to calcite biomineralization by fungi remain incompletely understood and more research is necessary, posing new exciting questions linked to microbial biomineralization processes.

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Calcium in fungi

Cited by 63 publications

References 86 publications

Calcium and Dipodascopsis uninucleata

Calcium and Dipodascopsis uninucleata

Cytosolic calcium homeostasis in fungi: roles of plasma membrane transport and intracellular sequestration of calcium.

Role of Fungi in the Biomineralization of Calcite

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