Hyphal Tip Bursting in Mucor rouxii: Antagonistic Effects of Calcium Ions and Acid

Dow, J. M.; Rubery, P. H.

doi:10.1099/00221287-91-2-425

Cited by 17 publications

(6 citation statements)

References 9 publications

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“…That this did not occur means the fungal nanoparticles were usually released either as a result of atmospheric processing of larger ejected particles or by another process at the land surface. The broad time scale over which chitin correlated with rain suggests the importance of some post-rain process, possibly fungal spore germination and/ or chemically or osmostically induced bursting (32)(33)(34)(35).…”

Section: Downloaded Frommentioning

confidence: 99%

Atmospheric fungal nanoparticle bursts

2020

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Aerosol nanoparticles play an important role in the climate system by affecting cloud formation and properties, as well as in human health because of their deep reach into lungs and the circulatory system. Determining nanoparticle sources and composition is a major challenge in assessing their impacts in these areas. The sudden appearance of large numbers of atmospheric nanoparticles is commonly attributed to secondary formation from gas-phase precursors, but in many cases, the evidence for this is equivocal. We report the detection of a mode of fungal fragments with a mobility diameter of roughly 30 nm released in episodic bursts in ambient air over an agricultural area in northern Oklahoma. These events reached concentrations orders of magnitude higher than other reports of biological particles and show similarities to unclarified events reported previously in the Amazon. These particles potentially represent a large source of both cloud-forming ice nuclei and respirable allergens in a variety of ecosystems.

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Section: Downloaded Frommentioning

confidence: 99%

Atmospheric fungal nanoparticle bursts

2020

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“…As a second messenger, Ca 2. may participate in signal transduction pathways for cellular activities (Jackson and Heath 1993) including: branching and induction of new tips (Reissing andKinney 1983, Schmid and, cytoplasmic movement (McKerracher and Heath 1986), vesicle fusion with the plasma membrane (Baydoun and Northcote 1980), and stabilization of cell walls by cross-linking newly secreted wall polysaccharide (Dow and Rubery 1975).…”

Section: Introductionmentioning

confidence: 99%

Calcium and tip growth inNeurospora crassa

Silverman‐Gavrila

Lew

2000

Protoplasma

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Summary. We examined the ionic regulation of tip growth in Neurospora crassa by a combination of electrophysiology and confocal microscopy. To determine if transmembrane ionic fluxes are required for tip growth, we voltage clamped the membrane from -200 to +50 mV. In this voltage range, transmembrane ionic fluxes would either reverse (e.g., K +) or change dramatically (e.g., Ca > influx) but had no effect on hyphal growth rates. Therefore, ionic fuxes (including Ca > influx) may not be required for tip growth. However, intracellular Ca 2+ may still play an obligatory role in tip growth. To assess this possibility, we first increased cytosolic Ca 2+ directly by ionophoresis. Elevated Ca 2 § induced subapical branch initiation, often multiple tips. At hyphal tips, fluorescence ratio imaging using fluo-3 and fura-red revealed a pronounced tip-high Ca 2 § gradient within 10 gm of the tip in growing hyphae which was not observed in nongrowing hyphae. Injection of the Ca > chelator 1,2-bis(ortho-aminophenoxy)ethane-N,N,N',N'-tetrapotassium acetate consistently inhibited growth concomitantly with a depletion of intracellular Ca 2+ and dissipation of the tip-high gradient. We conclude that Ca 2+ plays a regulatory role in tip initiation and the maintenance of tip growth. Because plasma membrane ionic fluxes do not play a role in tip growth, we suggest that the tip-high Ca 2+ gradient is generated from intracellular Ca 2. stores in the ascomycete N. crassa.

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“…Ca2+ ions appear to be generally required for growth and sporulation (Silver, 1977;Pitt & Ugalde, 1984;Ohya et al, 1986), but their function is unclear. There is evidence that Ca2+ ions help maintain the ionic permeability of the plasma membrane (Slayman, 1965;Van Brunt et al, 1982) and stabilize cell walls (Dow & Rubery, 1975). A role in the regulation of apical extension is suggested by the observation that calcium ionophores induce branching in Neurospora and AchZya (Reissig & Kinney, 1983;; and also by the gradient of intracellular Ca2+ that Reiss & Herth (1979) noted in Achlya.…”

Section: Introductionmentioning

confidence: 99%

Dual Roles for Calcium Ions in Apical Growth of Neurospora crassa

Schmid

Harold

1988

Microbiology

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We report initial attempts to define the role of Ca2+ in the polarized extension of Neurospora crassa. Growth of the organism was diminished in media containing less than 1 mM-Ca2+; extension was more severely impaired than biomass synthesis, resulting in the formation of stubby, bulbous hyphae, even of spherical cells. Reduced extension and abnormal morphology were correlated with the loss of surface-bound Ca2+, probably associated with the cell wall. Intracellular Ca2+ may be represented by material that fluoresces brightly in the presence of chlortetracycline. Punctate fluorescent bodies and diffuse fluorescence were both arrayed in a longitudinal gradient, maximum apically. Addition of the calcium ionophore A23 187 induced dissipation of the fluorescence; concurrently, the hyphae lost as much as one half of their Ca2+ content. Extension continued almost unabated, but multiple branches quickly emerged from the apex. The observations suggest that a cytoplasmic Ca2+ gradient is not required for polarized extension, but may play a role in ensuring the dominance of the apex.

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Hyphal Tip Bursting in Mucor rouxii: Antagonistic Effects of Calcium Ions and Acid

Cited by 17 publications

References 9 publications

Atmospheric fungal nanoparticle bursts

Atmospheric fungal nanoparticle bursts

Calcium and tip growth inNeurospora crassa

Dual Roles for Calcium Ions in Apical Growth of Neurospora crassa

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