Functional characterization of lipopolysaccharide derived from symbiotic bacteria in rice as a macrophage-activating substance

Anticancer Res. 2011 Jul;31(7):2467-76.


Background and aim: Lipopolysaccharide derived from a symbiotic bacterium in wheat (Pantoea agglomerans, LPSp) has shown multiple positive effects, such as prophylactic, antiallergic and antitumour effects, without serious side-effects. LPSp has differential biological activities in comparison to other LPS, such as those from Escherichia coli (LPSe). The only difference between LPSp and LPSe is in the O-antigen polysaccharide structure (O-PS). This led us to the hypothesis that the O-PS structure would seem to participate in biological activities. Thus, the characterization of properties of O-PS in LPS is of the utmost importance for understanding cell activation in the maintenance of homeostasis. However, little is known about the correlation between the O-PS structure of LPS and its biological activities. In this study, we extracted LPS derived from a symbiotic bacterium in rice (strain A46, related species of Pantoea), which has a long history of use in foods, and investigated its putative structures and functions.

Materials and methods: LPS derived from strain A46 was prepared using a hot phenol extraction method. The properties of LPS-A46 were analysed by thin-layer chromatography, Tricine SDS-PAGE and Western blotting. The function of LPS-A46 was analyzed by quantative real-time PCR and flow cytometry using THP-1 cells and Peripheral blood mononuclear cell (PBMC) derived macrophages.

Results: In Tricine SDS-PAGE, high molecular mass LPS-A46 had a molecular mass lower than that of LPSp. In Western blotting, LPS-A46 reacted with lipid A antibody but did not react with an O-PS antibody of LPSp. In comparison to other LPS, LPS-A46 induced a differential cytokine gene expression profile in THP-1 cells and PBMC-derived macrophages.

Conclusion: The present study suggests that LPS derived from symbiotic bacterium in rice is a bioactive functional LPS which may have different functional activities compared to other types of LPS.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Cell Line / drug effects
  • Cell Line / metabolism
  • Chromatography, Thin Layer
  • Cross Reactions
  • Cytokines / biosynthesis
  • Cytokines / genetics
  • Drug Evaluation, Preclinical
  • Electrophoresis, Polyacrylamide Gel
  • Humans
  • Limulus Test
  • Lipid A / immunology
  • Lipopolysaccharides / chemistry
  • Lipopolysaccharides / isolation & purification
  • Lipopolysaccharides / pharmacology*
  • Lymphocyte Activation / drug effects
  • Macrophage Activation / drug effects*
  • Macrophages / drug effects
  • Macrophages / metabolism
  • Micelles
  • Molecular Structure
  • Molecular Weight
  • Monocytes / drug effects
  • Monocytes / metabolism
  • O Antigens / chemistry*
  • Oryza / microbiology*
  • Pantoea / chemistry*
  • Structure-Activity Relationship


  • Cytokines
  • Lipid A
  • Lipopolysaccharides
  • Micelles
  • O Antigens