New information on the mechanism of forcible ascospore discharge from Ascobolus immersus

Fischer, Mark W. F.; Cox, Justin C.; Davis, Diana J.; Wagner, Andrew; Taylor, Richard T.; Huerta, Alfred J.; Money, Nicholas P.

doi:10.1016/j.fgb.2004.03.005

Cited by 41 publications

(28 citation statements)

References 20 publications

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“…Pa . s and p 0 ¼ 2 atm [27], the predicted elastic modulus of the apical ring is E * % 1 MPa, consistent with the elastic moduli of soft biological materials [28]. To quantify energy losses within this system, figure 4b also shows contours (grey Figure 2.…”

Section: Testing the Prediction With Morphological Datasupporting

confidence: 68%

A natural O-ring optimizes the dispersal of fungal spores

Fritz

Seminara

Roper

et al. 2013

J. R. Soc. Interface.

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The forcibly ejected spores of ascomycete fungi must penetrate several millimetres of nearly still air surrounding sporocarps to reach dispersive airflows, and escape is facilitated when a spore is launched with large velocity. To launch, the spores of thousands of species are ejected through an apical ring, a small elastic pore. The startling diversity of apical ring and spore shapes and dimensions make them favoured characters for both species descriptions and the subsequent inference of relationships among species. However, the physical constraints shaping this diversity and the adaptive benefits of specific morphologies are not understood. Here, we develop an elastohydrodynamic theory of the spore's ejection through the apical ring and demonstrate that to avoid enormous energy losses during spore ejection, the four principal morphological dimensions of spore and apical ring must cluster within a nonlinear one-dimensional subspace. We test this prediction using morphological data for 45 fungal species from two different classes and 18 families. Our sampling encompasses multiple loss and gain events and potentially independent origins of this spore ejection mechanism. Although the individual dimensions of the spore and apical ring are only weakly correlated with each other, they collapse into the predicted subspace with high accuracy. The launch velocity appears to be within 2 per cent of the optimum for over 90 per cent of all forcibly ejected species. Although the morphological diversity of apical rings and spores appears startlingly diverse, a simple principle can be used to organize it.

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Section: Testing the Prediction With Morphological Datasupporting

confidence: 68%

A natural O-ring optimizes the dispersal of fungal spores

Fritz

Seminara

Roper

et al. 2013

J. R. Soc. Interface.

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“…For example, a mature ascus of Giberella zeae holds a liquid volume of ∼7×10 −15 m 3 with mannitol (4.7±2.2×10 −12 g), potassium (4.6×10 −11 g), and chloride (1.4×10 −11 g) as the main solutes (Trail et al, 2005). Glycerol and proline (37±6 and 8±3 mmol/L, respectively) were found in the ascus sap of Ascobolus immersus (Fischer et al, 2004). To our knowledge, other data on the chemical composition of ascus sap are not available.…”

Section: Fungal Species and Discharge Of Fungal Sporesmentioning

confidence: 99%

Contribution of fungi to primary biogenic aerosols in the atmosphere: wet and dry discharged spores, carbohydrates, and inorganic ions

et al. 2007

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Abstract. Biogenic aerosols play important roles in atmospheric chemistry physics, the biosphere, climate, and public health. Here, we show that fungi which actively discharge their spores with liquids into the air, in particular actively wet spore discharging Ascomycota (AAM) and actively wet spore discharging Basidiomycota (ABM), are a major source of primary biogenic aerosol particles and components. We present the first estimates for the global average emission rates of fungal spores.Measurement results and budget calculations based on investigations in Amazonia (Balbina, Brazil, July 2001) indicate that the spores of AAM and ABM may account for a large proportion of coarse particulate matter in tropical rainforest regions during the wet season (0.7-2.3 µg m −3 ). For the particle diameter range of 1-10 µm, the estimated proportions are ∼25% during day-time, ∼45% at night, and ∼35% on average. For the sugar alcohol mannitol, the budget calculations indicate that it is suitable for use as a molecular tracer for actively wet discharged basidiospores (ABS). ABM emissions seem to account for most of the atmospheric abundance of mannitol (10-68 ng m −3 ), and can explain the observed diurnal cycle (higher abundance at night). ABM emissions of hexose carbohydrates might also account for a significant proportion of glucose and fructose in air particulate matter (7-49 ng m −3 ), but the literature-derived ratios are not consistent with the observed diurnal cycle (lower abundance at night). AAM emissions appear to account for a large proportion of potassium in air particulate matter over tropical rainforest regions during the wet season (17-43 ng m −3 ), and they can also explain the observed diurnal cycle (higher abundance at night). The results of our investigations and budget calculations for tropical rainforCorrespondence to: W. Elbert (elbert@mpch-mainz.mpg.de) est aerosols are consistent with measurements performed at other locations.Based on the average abundance of mannitol reported for extratropical continental boundary layer air (∼25 ng m −3 ), we have also calculated a value of ∼17 Tg yr −1 as a first estimate for the global average emission rate of ABS over land surfaces, which is consistent with the typically observed concentrations of ABS (∼10 3 -10 4 m −3 ; ∼0.1-1 µg m −3 ). The global average atmospheric abundance and emission rate of total fungal spores, including wet and dry discharged species, are estimated to be higher by a factor of about three, i.e. ∼1 µg m −3 and ∼50 Tg yr −1 . Comparisons with estimated rates of emission and formation of other major types of organic aerosol (∼47 Tg yr −1 of anthropogenic primary organic aerosol; 12-70 Tg yr −1 of secondary organic aerosol) indicate that emissions from fungi should be taken into account as a significant global source of organic aerosol. The effects of fungal spores and related chemical components might be particularly important in tropical regions, where both physicochemical processes in the atmosphere and biological activity at the Earth's sur...

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“…This is what happens in the process of ballistospore discharge in mushrooms and basidiomycete yeasts. (26,27) Substituting these values into Eq. (6), we see that 2 milliseconds after the initial launch, the displacement due to the initial velocity is about 400 µm = 0.4 mm and the displacement caused by diffusion is less than 0.1 µm:…”

Section: Inertial Time Scale and Reduction To The Overdamped Langevinmentioning

confidence: 99%

Mathematical and Computational Methods for Studying Energy Transduction in Protein Motors

Wang

Elston²

2006

J Stat Phys

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Protein motors play a central role in many cellular functions. Due to the small size of these molecular motors, their motion is dominated by high viscous friction and large thermal fluctuations. There are many levels of modeling molecular motors: from simple chemical kinetic models with a small number of discrete states to all atom molecular dynamics simulations. Here we describe a mathematical framework for an intermediate level of description. In this approach the major conformational changes of the motor protein are treated as continuous motions and changes in the chemical state of the motor are modeled as discrete Markov transitions. We discuss a numerical method for solving the Fokker-Planck equations that result from this mathematical framework and describe its extension to solving motor-cargo systems. We show that when the potential is discontinuous, detailed balance is a necessary condition for numerical convergence. We study the behavior of a motor-cargo system where the motor is driven by a tilted periodic potential. In particular, we derive a formula for the effective diffusion coefficient in the weak spring limit and analytically show that if the ratio of the motor size to that of the cargo is sufficiently large, then the velocity does not obtain its maximum value in the weak spring limit.

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New information on the mechanism of forcible ascospore discharge from Ascobolus immersus

Cited by 41 publications

References 20 publications

A natural O-ring optimizes the dispersal of fungal spores

A natural O-ring optimizes the dispersal of fungal spores

Contribution of fungi to primary biogenic aerosols in the atmosphere: wet and dry discharged spores, carbohydrates, and inorganic ions

Mathematical and Computational Methods for Studying Energy Transduction in Protein Motors

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