title: Is the periplasm continuous in filamentous multicellular cyanobacteria?
abstract: Filamentous, heterocyst-forming cyanobacteria are multicellular organisms in which individual cells exchange nutrients and, presumably, regulatory molecules. Unknown mechanisms underlie this exchange. Classical electron microscopy shows that filamentous cyanobacteria bear a Gram-negative cell wall comprising a peptidoglycan layer and an outer membrane that are external to the cytoplasmic membrane, and that the outer membrane appears to be continuous along the filament of cells. This implies that the periplasmic space between the cytoplasmic and outer membranes might also be continuous. We propose that a continuous periplasm could constitute a communication conduit for the transfer of compounds, which is essential for the performance of these bacteria as multicellular organisms.
authors.affiliation: Instituto de Bioquímica Vegetal y Fotosíntesis, C.S.I.C.-Universidad de Sevilla, Américo Vespucio 49, E-41092 Seville, Spain. eflores@ibvf.csic.es
authors.forename: Enrique
authors.initials: E
authors.lastname: Flores
authors.forename: Antonia
authors.initials: A
authors.lastname: Herrero
authors.forename: C Peter
authors.initials: CP
authors.lastname: Wolk
authors.forename: Iris
authors.initials: I
authors.lastname: Maldener
mesh_terms: D002462:Cell Membrane / Q000648:ultrastructure; D002473:Cell Wall / Q000648:ultrastructure*; D000458:Cyanobacteria / Q000166:cytology* / Q000502:physiology* / Q000648:ultrastructure; D019897:Periplasm / Q000648:ultrastructure*