Evolutionary Considerations in Studying the Sialome: Sialic Acids and the Host-Pathogen Interface

Sialic acids (Sias) are a family of acidic 9-carbon backbone monosaccharides found at terminal positions of glycan chains in mammals. While Sias are required for critical intrinsic functions of mammals, they are also of particular significance at the host-pathogen interface, where they can be exploited or mimicked by pathogenic microbes. Here we discuss ongoing studies related to the functional and evolutionary significance of sialic acids on host-pathogen interactions. To place these interactions in a broader context, we consider the diversity, distribution, biosynthesis, and evolution of Sias. We also review common glycan analysis techniques that can result in loss of Sias or Sia modifications and finally suggest a "Sialome" project for archiving information about Sias in nature.