Gravity susception by buoyancy: floating lipid globules in sporangiophores of Phycomyces

  title={Gravity susception by buoyancy: floating lipid globules in sporangiophores of Phycomyces},
  author={Franz Grolig and Heinz Herkenrath and T. Pumm and Andrea Gross and Paul Galland},
To elucidate the mechanisms of gravity susception that operate in the sporangiophore of Phycomyces blakesleeanus, we characterized the function and topography of a large apical complex of lipid globules. Stage-1 sporangiophores (without sporangium) possess a roughly spherical complex of 100–200 large lipid globules whose center is localized 110 μm below the apex. The complex of lipid globules (CLG) is rather stable and is kept in place by positioning forces that resist centrifugal accelerations… 
Gravireception of the sporangiophore of Phycomyces blakesleeanus
Abstract The sporangiophore of the zygomycete Phycomyces blakesleeanus displays negative gravitropism that manifests with a latency of some 5–15 min after stimulation. Sporangiophores possess an
Gravisusception by buoyancy: a mechanism ubiquitous among fungi?
In the vegetative sporangiophore of the zygomycete Phycomyces blakesleeanus some 200 large lipid globules form a conspicious spherical complex which is positioned in a dense mesh of filamentous actin about 100 μm below the growing tip of the apex, meeting basic physical criteria for a possible function of gravisusception.
The sporangiophore of Phycomyces blakesleeanus: a tool to investigate fungal gravireception and graviresponses.
Additional phenomena pertaining to gravireception, specifically adherence to the novel exponential law and non-adherence to the classical resultant law of gravitropism, were for the first time investigated for Phycomyces.
Actin cytoskeleton and organelle movement in the sporangiophore of the zygomycete Phycomyces blakesleeanus.
The zonation of the cytoskeleton density correlated well with the local growth rates at the tip of the sporangiophore, and appears thus as a structural prerequisite for growth and bending.
Gravitropism in Phycomyces: violation of the so-called resultant law - evidence for two response components.
The authors' data are at variance with the so-called resultant law and imply that gravitropic orientation cannot depend exclusively on the classical sine stimulus and must also be controlled by the cosine stimulus acting parallel to the longitudinal axis of the gravisensing organ.
Optospectroscopic Detection of Primary Reactions Associated with the Graviperception of Phycomyces. Effects of Micro- and Hypergravity1
The graviperception of sporangiophores of the fungus Phycomyces blakesleeanus involves gravity-induced absorbance changes (GIACs) that represent primary responses of gravitropism, and these GIACs have a latency of about 20 ms or shorter and are thus the fastest graviresponses ever measured for fungi, protists, and plants.
Graviresponses in fungi and slime molds
The analysis of gravisensing in fungi has not yet proceeded as far as in other systems, such as sensory cells for maintenance of equilibrium in crustaceans and vertebrates, Chara rhizoids or plant
Gravitaxis in Euglena.
It has been proven that this flagellate possesses a physiological gravireceptor and an active orientation for Euglena gracilis, and the threshold for gravity perception was determined and physiological, biochemical and molecular components of the signal transduction chain have been identified.
Ca2+ and H+ Ion Fluxes near the Surface of Gravitropically Stimulated Phycomyces Sporangiophore
  • B. Živanović
  • Chemistry, Medicine
    Annals of the New York Academy of Sciences
  • 2005
The single‐celled fungus Phycomyces blakesleeanus forms vertically oriented sporangiophores from hyphae, which display a negative gravitropic response, and noninvasive H+ and Ca2+ ion‐selective microelectrode measurements reveal direction of ion fluxes depended on developmental stage of sporang iophores and changed with gravistimulation.
Photomorphogenesis and Gravitropism in Fungi
There are indications that other fungi, even other ascomycetes, have molecular mechanisms for photoreception that are different from the one in N. crassa, and it is becoming clear that there are limits to the use of N.crassa as a model for fungal photobiology.


Gravitropism in Phycomyces: a role for sedimenting protein crystals and floating lipid globules
It is proposed that both the sedimenting protein crystals and the upward-floating globules are involved in gravisensing.
Tropic Responses of Phycomyces Sporangiophores to Gravitational and Centrifugal Stimuli
  • D. S. Dennison
  • Chemistry, Medicine
    The Journal of general physiology
  • 1961
Experiments in which sporangiophores are centrifuged in an inert dense fluid indicate that the sensory mechanism of the transient response is closely related to the physical deformation of the growing zone caused by the action of the gravitational-centrifugal force on the sporang iophore as a whole.
Gravitropism in Phycomyces: threshold determination on a clinostat centrifuge.
The absolute sensitivity of sporangiophores of Phycomyces blakesleeanus to centrifugal acceleration was determined on a clinostat centrifuge, characterized by a polar angle and an aiming-error angle, which indicates the deviation of the plane of bending from the vector of the centrifugation.
Blue-light perception in stage-1 sporangiophores of Phycomyces: a role for apical lipid globules?
The results suggest a possible role for the lipid globules in the blue-light perception of stage-1 sporangiophores, and indicate that the sensitivity was greatest when the globules rather than the globule-free areas were irradiated.
  • M. Zalokar
  • Biology, Medicine
    The Journal of cell biology
  • 1969
It was concluded that cell organelles, sedimented by centrifugation of living sporangiophores, remain alive and can be used for biochemical studies.
Statoliths in Phycomyces: characterization of octahedral protein crystals.
To identify the molecular mechanisms of gravitropism in the fungus Phycomyces blakesleeanus we determined several biochemical and physical parameters of paracrystalline protein bodies, so-called
The fine structure ofPhycomyces
The cytological organization of the apices of sporangiophores and hyphae of Phycomyces Blakesleeanus was studied by means of light- and electron microscopy and found that microtubules are found to run along the cylindrical cell's axis at a distance from the cell wall, and extend to the extreme apex of the cell.
Flammulina as a model system for fungal graviresponses
Gravitropic raising of intact stems or segments derived from the transition zone requires positional information which can be accomplished by three major, coordinated events: gravisensing by the individual hyphae within the Transition zone, unidirectional signalling by means of a soluble growth factor creating a vertical concentration gradient, and translation of the concentration signal into elongation growth.
Parameters governing gravitropic response of sporangiophores inPhycomyces blakesleeanus
The sporangiophores (spphs) of the fungusPhycomyces blakesleeanus bend upward in a negative gravitropic response when placed in a horizontal position in the dark. The spphs of a hypergravitropic
The fine structure of Phycomyces. 1. Autophagic vesicles.
  • R. M. Thornton
  • Biology, Medicine
    Journal of ultrastructure research
  • 1967
Findings suggest that certain endoplasmic cisternae of the sporangiophore are engaged in the isolation and lysis of cytoplasm, and that the vesicle membranes originate from nuclear membranes.