Immunology
The lipopolysaccharide core oligosaccharide of Burkholderia plays a critical role in maintaining a proper gut symbiosis with the bean bug Riptortus pedestris
Lipopolysaccharide, the outer cell-wall component of Gram-negative bacteria, has been shown to be important for symbiotic associations. We recently reported that the lipopolysaccharide O-antigen of Burkholderia enhances the initial colonization of the midgut of the bean bug, Riptortus pedestris. However, the midgut-colonizing Burkholderia symbionts lack the O-antigen but display the core oligosaccharide on the cell surface. In this study, we investigated the role of the core oligosaccharide, which directly interacts with the host midgut, in the Riptortus–Burkholderia symbiosis.Activation of Human Toll-like Receptor 4 (TLR4)·Myeloid Differentiation Factor 2 (MD-2) by Hypoacylated Lipopolysaccharide from a Clinical Isolate of Burkholderia cenocepacia
Background: The Burkholderia cenocepacia lipid A is hypoacylated.Results: Aminoarabinose residues in lipid A contribute to Burkholderia lipid A binding to the TLR4·MD-2 complex.Conclusion: A novel mode of Burkholderia lipopolysaccharide-TLR4·MD-2 interactions promotes inflammation.Significance: Modifications of the lipid A structure enhance proinflammatory responses of hypoacylated lipopolysaccharide.Insect Gut Symbiont Susceptibility to Host Antimicrobial Peptides Caused by Alteration of the Bacterial Cell Envelope
Background: The elucidation of molecular changes of symbionts is important for understanding symbiotic adaptation.Results: Insect gut symbionts are highly susceptible to host immunity because of dramatic cell envelope changes.Conclusion: Cell envelope changes in gut symbionts are required for successful symbiosis with hosts.Significance: Biochemical analyses of intact gut symbionts revealed a novel mechanism of gut symbiosis.
