EACH type of bacterium has a unique sugary coating, but this superficial sweetness carries a bitter message for any organism it infects. Now the offending sugars can be rapidly identified by a 鈥渇ingerprinting鈥� test.
The coating consists of more than 100 different sugars, known as surface glycans, which the bacterium can mask or display depending on whether it is invading a cell, dodging the immune system or communicating with other cells. Knowing which glycans are displayed and when could lead to ways of blocking and diagnosing infections, but has largely remained a mystery because the sugars are difficult to detect.
Lara Mahal and colleagues at the University of Texas at Austin have a simple solution. Bacteria are placed on a glass plate containing dots of different proteins known as lectins, each of which binds to only one sugar. By noting which of the proteins on this microarray the bacteria stick to, Mahal can deduce which sugars are present (Nature Chemical Biology, DOI: 10.1038/nchembio767).
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