Sugars, bugs and us

Glycan-mediated host–microbe interactions are critical to col-onization by and maintenance of our helpful commensal micro-biota, as well as to recognition and control of pathogenic microbes that can do us harm. This is a rapidly expanding field of research, so we are delighted that our first collection of themed reviews in Glycobiology is on this topic. The first article, by Bergstrom and Xia, describes the features of intestinal mucins, including the structures and synthesis of the O-glycans that are essential for the function of mucins as a physical barrier between microbes and intestinal epithelium. This review also discusses the disease states, such as inflamma-tory bowel disease, that occur when the mucin barrier is dis-rupted by loss of expression of specific glycosyltransferases that create the O-glycans on mucins. However, the intestinal mucin barrier is not simply