No endospore formation confirmed in members of the phylum Proteobacteria.

Endospore formation is used by members of the phylum Firmicutes to withstand extreme environmental conditions. Several recent studies have proposed endospore formation in species outside of Firmicutes, particularly in and , members of the phylum Proteobacteria. Here, we aimed to investigate endospore formation in these two species by using advanced imaging and analytical approaches.

The Mycobacterial Cell Envelope: A Relict From the Past or the Result of Recent Evolution?

Mycobacteria are well known for their taxonomic diversity, their impact on global health, and for their atypical cell wall and envelope. In addition to a cytoplasmic membrane and a peptidoglycan layer, the cell envelope of members of the order , which include , also have an arabinogalactan layer connecting the peptidoglycan to an outer membrane, the so-called "mycomembrane." This unusual cell envelope composition of mycobacteria is of prime importance for several physiological processes such as protection from external stresses and for virulence.