Tooth Furry

Like humans, bacteria are social creatures – here they’ve built a thriving community inside a human mouth. Tiny fluorescent probes highlight nine different types of bacteria in different colours using their unique DNA sequences to tell them apart – a technique called fluorescence in situ hybridization (FISH). Researchers are fascinated by how the Corynebacterium (purple), Actinomyces (white) and Leptotrichia (light blue) bacteria, among others, organise themselves into furry 'hedgehog' formations like the three shown here side-by-side. Studying the geography of bacterial communities, or microbiomes, gives clues to how they exchange chemicals to communicate, grow and survive. It is also quite unsettling – this community was found inside the dental plaque of volunteers who hadn’t brushed their teeth for two days. A sobering reminder to stop reading and go to find some floss.

Written by John Ankers

John Ankers

Writer

A former researcher in systems biology, John is now an online biology tutor and professional coach supporting the wellbeing of scientists and NHS professionals. He's writing, too, of course.

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• Image from work by Jessica L. Mark Welch and colleagues
• The Forsyth Institute, Cambridge, MA, USA
• Image copyright held by original authors; image reproduction permitted by PNAS
• Published in PNAS, January 2016