Phycomyces

Ahlquist, C.N.; Gamow, R. Igor

doi:10.1104/pp.51.3.586

Cited by 31 publications

(18 citation statements)

References 3 publications

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“…Yeast: Saccharomyces cerevisiae () ) ) [23]. Fungi: Phycomyces (ᮀ) [24 -26] and Saprolegnia ferax ( ᭪᭪ ) [24,27,28]. Guinea pig cochlear outer hair cell (᭹) [29].…”

Section: P H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

Growth of Walled Cells: From Shells to Vesicles

Boudaoud

2003

Phys. Rev. Lett.

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The growth of isolated walled cells is investigated. Examples of such cells range from bacteria to giant algae, and include cochlear hair, plant root hair, fungi, and yeast cells. They are modeled as elastic shells containing a liquid. Cell growth is driven by fluid pressure and is is similar to a plastic deformation of the wall. The requirement of mechanical equilibrium leads to two new scaling laws for cell size that are in quantitative agreement with the compiled biological data. Given these results, possible shapes for growing cells are computed by analogy with those of vesicle membranes.

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“…Yeast: Saccharomyces cerevisiae () ) ) [23]. Fungi: Phycomyces (ᮀ) [24 -26] and Saprolegnia ferax ( ᭪᭪ ) [24,27,28]. Guinea pig cochlear outer hair cell (᭹) [29].…”

Section: P H Y S I C a L R E V I E W L E T T E R Smentioning

confidence: 99%

Growth of Walled Cells: From Shells to Vesicles

Boudaoud

2003

Phys. Rev. Lett.

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“…A recent (1). This increase in mechanical extensibility of the cell wall is accompanied by a transition in the mechanical properties of the cell wall from a basically elastic structure to a more plastic structure.…”

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confidence: 99%

Phycomyces: A Change in Mechanical Properties after a Light Stimulus

Ortega¹,

Gamow²,

Ahlquist³

1975

Plant Physiol.

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The following experiments were performed in an attempt to elucidate any possible changes in cell wall extensibility that may occur as a result of a saturating light stimulus. In each experiment, the same individual sporangiophore was used to ensure measurement of real changes within any given sporangiophore and not some random variation that may occur between sporangiophores. MIATERIALS AND METHODSThe sporangiophores were grown in glass shell vials containing 4.0%0 potato dextrose agar with 1.0%-yeast extract under diffuse incandescent light. The sporangiophores were grown and tested at 22 C. Tensile loads were applied with an Instron Model T.M. tension-compression machine equipped with a Model A load cell set at high sensitivity (2 g full scale) to stage IVb sporangiophores at a constant displacement rate of 2.54 mmj"min. These rates ensured that any measured changes between a light-stimulated and dark-adapted state (dark-adapted in red light for 40 min) could not be explained as an artifact of increased growth rates. Before each tensile test the sporangiophore was dark-adapted for at least 40 min in a box (15 cm X 15 cm X 13 cm) constructed of transparent red Plexiglas. This box contained a light bulb (Sylvania, 25 w, 120 v, soft white light) which could be turned off and on from outside the box. All stimuli were pulse-up stimuli of 10-sec or 2-min duration. Tensile loads were transmitted to the sporangiophore using a 0.2-mm Nichrome wire hook which passed first through a small hole in the Plexiglas box and was then attached directly under the sporangium (Fig. 1).The data for determining extension as a function of tensile load were obtained using two separate methods. First, the imposed displacement was calculated from the product of the machine extension rate and the time required to reach a particular tensile load. This method does not measure the actual extension of the sporangiophore since part of the imposed displacement is used to deform elastically the loading hook, but this method does measure actual changes in the extension of the sporangiophore since the extension of the loading hook is a linear function of load. In the second method, the actual extension was measured from photographs of the sporangiophore with starch markers on the growth zone. The photographs were taken with a 35-mm Nikon FTN single lens reflex camera equipped with bellows ex-333 www.plantphysiol.org on May 10, 2018 -Published by Downloaded from

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“…Curvature occurred with commencement of elongation (photographs 20-24). Bar = 100 Ixm The rotation of the Pilobolus sporangiophore may be interpreted in terms of a reorientation of the microfibrils in the cell wall, as previously proposed for Phycomyces (Ahlquist and Gamow 1973;Gamow and Brttger 1979). In Phycomyces, the microfibrils in the growth zone are assumed to be initially orientated in a nearly transverse righthanded direction and anchored at the basal ends.…”

Section: Discussionmentioning

confidence: 98%

Analysis of growth and rotational behavior of sporangiophores in Pilobolus crystallinus (Wiggers) Tode

Ootaki

Ishikawa

Konno

et al. 1993

Planta

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Abstract. The growth and rotation of the sporangiophore of Pilobolus crystallinus, which are important factors in its phototropic behavior, were analyzed throughout its development. The sporangiophore initial emerged from the trophocyst and elongated at the extreme tip without rotating. The elongation rate of the sporangiophore apex then gradually decreased and the apex expanded radially to produce the sporangium, but no rotation occurred. A transient cessation of elongation after sporangium development was followed by resumption of both elongation and radial expansion in the region beneath the sporangium developing the subsporangial vesicle. Rotation was not obvious at this stage. Radial expansion of the subsporangial vesicle continued at a decreasing rate until full size was reached. Elongation then recommenced in the newly established growth zone in the upper region of the sporangiophore just beneath the subsporangial vesicle. During this period of growth, the sporangiophore rotated in a clockwise direction as viewed from above. All growth and rotation ceased about 1 h before ejection of the sporangium into the air. Based on these results, a modified classification of the developmental stages has been proposed.

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Phycomyces

Cited by 31 publications

References 3 publications

Growth of Walled Cells: From Shells to Vesicles

Growth of Walled Cells: From Shells to Vesicles

Phycomyces: A Change in Mechanical Properties after a Light Stimulus

Analysis of growth and rotational behavior of sporangiophores in Pilobolus crystallinus (Wiggers) Tode

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