Cultivation of elusive microbes unearthed exciting biology

Abstract

Many newly-discovered microbial phyla have been studied solely by cultivation-independent techniques such as metagenomics. Much of their biology thus remains elusive, because the organisms have not yet been isolated and grown in the lab. Katayama et al. lift the curtain on some intriguing biology by cultivating and studying bacteria from the elusive OP9 phylum (Atribacterota).

Fig. 1. Alternative interpretations of the cell biology of Atribacter laminatus.

Comparison of the cell plans of a typical Gram-negative bacterium (a), Atribacter laminatus (b), and a typical eukaryotic cell (c), displayed both in the xy-plane (top row) and the xz-plane (bottom row). The gray dashed lines indicate the plane illustrated in the other orientation. Shown are three possible interpretations of the cell plan of A. laminatus. In scenario 1, favored by Katayama et al., A. laminatus has a nucleus-like compartment. Scenario 2 is reminiscent of a typical Gram-negative with an additional S-layer as outer layer. In scenario 3, the cytoplasmic membrane shows extensive invaginations. OM outer membrane, CM cytoplasmic membrane, ICM intra-cytoplasmic membrane.