Birgit Luef of Trondheim University in Norway and Chris Brown of the University of California, Berkeley, talk with Jeff Fox about ultrasmall bacteria.

Birgit Luef and Chris Brown of Jill Banfield’s lab at UC Berkeley went looking for bacteria with small genomes. They found large numbers of organisms that not only had small genomes but also were extremely small in size—small enough to pass through a 0.2-micrometer filter, with many in the 250-nanometer range. Such ultrasmall bacteria are ubiquitous and diverse, and half of their genes are unique. Most are missing basic synthetic pathways, and they seem to be dependent on other organisms for metabolic products. Though it has not been possible to culture the organisms, genomic analyses reveal close similarities among large groups of them.

This research was featured in the June 2015 issue of Microbe.