A novel rhamno-mannan exopolysaccharide isolated from biofilms of Burkholderia multivorans C1576

Abstract

Burkholderia multivorans C1576 is a Gram negative opportunistic pathogen causing serious lung infection in cystic fibrosis patients. Considering that bacteria naturally form biofilms, and exopolysaccharides are recognized as important factors for biofilm architecture set-up, B. multivorans was grown both in biofilm and in non-biofilm mode on two different media in order to compare the exopolysaccharides biosynthesized in these different experimental conditions. The exopolysaccharides produced were purified and their structure was determined resorting mainly to NMR spectroscopy, ESI mass spectrometry and gas chromatography coupled to mass spectrometry. The experimental data showed that both in biofilm and non-biofilm mode B. multivorans C1576 produced a novel exopolysaccharide having the following structure: [Formula: see text]. About 50% of the 2-linked rhamnose residues are substituted on C-3 with a methyl ether group. The high percentage of deoxysugar Rha units, coupled with OMe substitutions, suggest a possible role for polymer domains with marked hydrophobic characteristics able to create exopolysaccharide junction zones favouring the stability of the biofilm matrix.

Tramesan, a novel polysaccharide from Trametes versicolor. Structural characterization and biological effects

“…The instrument was calibrated using a tune mixture provided by Bruker. In order to increase the detection sensitivity, oligosaccharides were reduced with NaBH 4 [ 25 ], to label the reducing end and subsequently permethylated [ 26 ], dissolved in a 1:1 chloroform: methanol mixture, 11mM NH 4 OAc and subjected to ESI-MS and MS 2 analyses. Samples were injected at 180 μL/h and detection was performed in the positive ion mode.…”

Fluorescence and NMR spectroscopy together with molecular simulations reveal amphiphilic characteristics of a Burkholderia biofilm exopolysaccharide

“…Bacterial growth and polysaccharide purification were performed according to Protocol II described in Ref. 9.…”

Biofilms produced by Burkholderia cenocepacia: influence of media and solid supports on composition of matrix exopolysaccharides

“…Furthermore, several other articles have shown that the polysaccharides involved in biofilm formation are very diverse in structure and are not only restricted to a few well-known macromolecules such as alginate, cellulose and poly-b-1,6-GlcNAc. An example among the BCC bacteria is the reference strain Burkholderia multivorans C1576; when it was grown on cellulose membranes deposited on YEM medium it produced cepacian, while on MH medium it biosynthesized a novel EPOL, containing rhamnose and mannose residues (Cuzzi et al, 2014;Dolfi et al, 2015). The polysaccharides involved in matrix formation probably share some common macromolecular properties, like the capability of interacting with proteins, lipids and other molecules in the biofilm, that render them particularly suitable for forming a polymeric network.…”