Three-dimensional reconstruction of bacteria with a complex endomembrane system

• Published in: PLoS biology Vol. 11; no. 5; p. e1001565
• Main Authors: Santarella-Mellwig, Rachel, Pruggnaller, Sabine, Roos, Norbert, Mattaj, Iain W, Devos, Damien P
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01.05.2013; Public Library of Science (PLoS)
• Subjects: Bacteria; Bacterial Proteins - metabolism; Biology; Cell Compartmentation; Cytoplasm; Deoxyribonucleic acid; DNA; Gram-negative bacteria; Intracellular Membranes - metabolism; Intracellular Membranes - ultrastructure; Membranes; Microbiological chemistry; Microbiology; Microscopy; Microscopy, Electron; Molecular biology; Physiological aspects; Planctomycetales - metabolism; Planctomycetales - ultrastructure; Norway; Cell Compartmentation; Microscopy, Electron; Planctomycetales; Intracellular Membranes; Bacterial Proteins
• ISSN: 1545-7885; 1544-9173; 1545-7885
• DOI: 10.1371/journal.pbio.1001565

The division of cellular space into functionally distinct membrane-defined compartments has been one of the major transitions in the history of life. Such compartmentalization has been claimed to occur in members of the Planctomycetes, Verrucomicrobiae, and Chlamydiae bacterial superphylum. Here we have investigated the three-dimensional organization of the complex endomembrane system in the planctomycete bacteria Gemmata obscuriglobus. We reveal that the G. obscuriglobus cells are neither compartmentalized nor nucleated as none of the spaces created by the membrane invaginations are closed; instead, they are all interconnected. Thus, the membrane organization of G. obscuriglobus, and most likely all PVC members, is not different from, but an extension of, the "classical" Gram-negative bacterial membrane system. Our results have implications for our definition and understanding of bacterial cell organization, the genesis of complex structure, and the origin of the eukaryotic endomembrane system.