Structure of the O-polysaccharide of the lipopolysaccharide produced by Taylorella asinigenitalis type strain (ATCC 700933).

This research investigates the structure of O-polysaccharide in the lipopolysaccharide produced by Taylorella asinigenitalis, a non-pathogenic bacterium found in the genital tract of male donkeys, to distinguish it from the similar but pathogenic Taylorella equigenitalis.

Understanding the Research Context

• The bacterium under investigation, Taylorella asinigenitalis (sp. nov), is a recently discovered nonpathogenic microorganism that is found in the genital tract of male donkeys.
• Interestingly, it bears similar phenotypic characteristics to Taylorella equigenitalis, a known pathogen responsible for a highly communicable horse disease known as contagious equine metritis.
• Given the impressive biological similarity, the researchers sought to identify differentiating features at the structural level, with the focus placed on the lipopolysaccharide (a structural molecule in the bacteria’s outer membrane).

Analysis of Lipopolysaccharide

• In bacterial species, lipopolysaccharides often possess a component known as O-polysaccharide (O-PS) that differs considerably between microbial species and can be used as basis of distinction.
• The researchers found that the O-PS of T. asinigenitalis consists of a linear unbranched chain of repeating disaccharide units.
• These units contain 1,3-linked pyranosyl residues of bacillosamine and beta-D-glucuronic acid.
• The structural formula for this biopolymer can be denoted as [–>3)-beta-D-QuipNAc4NAc-(1–>3)-beta-D-GlcpNAmA-(1–>]n.

Significance of the Findings

• The distinct chemical structure and the unique serological characteristics of the T. asinigenitalis O-PS set it apart from the O-PS of the Taylorella equigenitalis type strain.
• This finds application in diagnostics, facilitating accurate differentiation between pathogenic and non-pathogenic Taylorella sp. clinical isolates.
• The O-PS of T. asinigenitalis could potentially serve as a cell-surface target in diagnostic tests or experiments seeking to distinguish between the two bacterial species.