Biopolymer excreted by Pseudoalteromonas antarctica NF<inf>3</inf>, as a coating and protective agent of liposomes against dodecyl maltoside

A. De La Maza, L. Codech, O. Lopez, J. L. Parra, M. Sabés, J. Guinea

Research output: Contribution to journalArticleResearchpeer-review

4 Citations (Scopus)

Abstract

The ability of an exopolymer of glycoproteic character (GP) excreted by a new gram-negative species Pseudoalteromonas antarctica NF3, to coat phosphatidylcholine (PC) liposomes and to protect these bilayers against the action of the nonionic surfactant dodecyl maltoside was investigated. Transmission electron microscopy (TEM) micrographs of freeze fractured liposome/GP aggregates reveal that the addition of the glycoprotein to liposomes led to the formation of a film (polymer adsorbed onto the bilayers) that tightly coated PC bilayers. The complete coating was already achieved at a PC: GP weight ratio of about 9:1. Image analysis profiles of digitalized TEM micrographs (PC: GP weight ratio 8:2) show that this film was formed by a multilayer structure. The periods of the average distance of the pattern ordering in layer structures (9-10 layers) were of about 2-3 nm and the thickness of the complete film was of about 25 nm. Higher amounts of glycoprotein resulted in a growth of this film, which exhibited at the highest proportion of this compound (50% in weight) a multifilm structure. An increasing resistance of liposomes to be affected by dodecyl maltoside both at subsolubilizing and solubilizing levels occurred as the proportion of the glycoprotein in the system rose, although this protective effect was more effective at low proportions of this compound (PC: GP weight ratios from 9:1 to 8:2). Thus, although a direct dependence was found between the growth of the enveloping structure and the resistance of the coated liposomes to be affected by the surfactant, the more effective protection occurred when this structure was a thin film formed by the assembly of various layers of GP of about 2-3 nm.
Original languageEnglish
Pages (from-to)579-588
JournalBiopolymers
Volume50
Issue number6
DOIs
Publication statusPublished - 1 Jan 1999

Keywords

  • Differential scanning calorimetry
  • Exopolymer of glycoproteic character
  • Freeze-fracture TEM
  • New bacterial species
  • Nonionic surfactant dodecyl maltoside
  • Permeability and static light scattering variations of liposome/glycoprotein aggregates
  • Phosphatidylcholine liposomes
  • Pseudoalteromonas antarctica NF 3
  • Solubilization of liposomes
  • Transmission electron microscopy (TEM)

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