title: Ultrastructural analysis of the extracellular matter secreted by the psychrotolerant bacterium Pseudoalteromonas antarctica NF3.
abstract: The psychrotolerant strain Pseudoalteromonas antarctica NF3, a Gram-negative bacterium isolated from muddy soil samples of Antarctica, secretes large amounts of a mucoid exopolymer with a high protein content. It has self-assembly properties and capacity to coat and protect liposomes against surfactants. We examined the ultrastructure of P. antarctica and the extracellular matter it secretes by transmission electron microscopy (TEM) after high-pressure freezing, freeze substitution (HPF-FS), and Epon embedding, and compared this with information obtained by conventional methods. The improvements brought about by HPF-FS to the ultrastructural preservation of the extracellular matter allowed us to establish for the first time, in P. antarctica NF3, the presence of two components: a large amount of cell-derived outer membrane vesicles containing proteins and a capsular polymer around the cells.
authors.affiliation: Scientific-Technical Services of the University of Barcelona, Barcelona, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Nevot
authors.forename: Victor
authors.initials: V
authors.lastname: Deroncele
authors.forename: Carmen
authors.initials: C
authors.lastname: López-Iglesias
authors.forename: Nuria
authors.initials: N
authors.lastname: Bozal
authors.forename: Jesús
authors.initials: J
authors.lastname: Guinea
authors.forename: Elena
authors.initials: E
authors.lastname: Mercade
mesh_terms: D005110:Extracellular Space / Q000378:metabolism; D046529:Microscopy, Electron, Transmission; D031161:Pseudoalteromonas / Q000378:metabolism / Q000648:ultrastructure*