Rapid wound responses ofSaprolegnia ferax hyphae depend upon actin and Ca2+-involving deposition of callose plugs

Autor: Roger R. Lew, I. B. Heath, N. N. Levina
Rok vydání: 2000
Předmět:
Zdroj: Protoplasma. 214:199-209
ISSN: 1615-6102
0033-183X
DOI: 10.1007/bf01279064
Popis: Growing hyphae of the oomyceteSaprolegnia ferax wounded by impalement with a ca. 0.2 μm diameter glass microelectrode normally respond within seconds with an apically directed cytoplasmic contraction followed by production of a plug which encases the electrode and occludes its recording of transmembrane potentials. This plug contains callose and Ca2+-associated membranes. To characterize the rapid wounding response, we disrupted specific filamentous (F) actin populations and Ca2+ regulation. Plug formation is inhibited by disruption of F-actin populations and low exogenous Ca2+ but not by inhibition of stretch-activated Ca2+ channels with Gd3+. Therefore, stretch-activated channels are not the immediate sensor. Instead, sensing may involve strain on the actin cytoskeleton which triggers the occlusion response. This wound response is qualitatively similar to the production of septa which isolate developing sporangia and seal severed hyphae, indicating the use of a normal basic cellular developmental system as a protective mechanism against environmental damage. The wound response is essential, since an inability to seal sites of mechanical damage is potentially catastrophic in acellular coenocytic organisms.
Databáze: OpenAIRE
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