Ultrastructure of the denitrifying methanotroph "Candidatus Methylomirabilis oxyfera," a novel polygon-shaped bacterium.
"Candidatus Methylomirabilis oxyfera" is a newly discovered denitrifying methanotroph that is unrelated to previously known methanotrophs. This bacterium is a member of the NC10 phylum and couples methane oxidation to denitrification through a newly discovered intra-aerobic pathway. In the present study, we report the first ultrastructural study of "Ca. Methylomirabilis oxyfera" using scanning electron microscopy, transmission electron microscopy, and electron tomography in combination with different sample preparation methods. We observed that "Ca. Methylomirabilis oxyfera" cells possess an atypical polygonal shape that is distinct from other bacterial shapes described so far. Also, an additional layer was observed as the outermost sheath, which might represent a (glyco)protein surface layer. Further, intracytoplasmic membranes, which are a common feature among proteobacterial methanotrophs, were never observed under the current growth conditions. Our results indicate that "Ca. Methylomirabilis oxyfera" is ultrastructurally distinct from other bacteria by its atypical cell shape and from the classical proteobacterial methanotrophs by its apparent lack of intracytoplasmic membranes.
Department of Microbiology, Institute for Water and Wetland Research, Radboud University Nijmegen, Nijmegen, The Netherlands.
Ming L
ML
Wu
Muriel C F
MC
van Teeseling
Marieke J R
MJ
Willems
Elly G
EG
van Donselaar
Andreas
A
Klingl
Reinhard
R
Rachel
Willie J C
WJ
Geerts
Mike S M
MS
Jetten
Marc
M
Strous
Laura
L
van Niftrik
D002462:Cell Membrane; D048430:Cell Shape; D015925:Cryopreservation; D055032:Electron Microscope Tomography; D004853:Epoxy Resins; D005613:Freeze Etching; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology; D016680:Genome, Bacterial; D021621:Imaging, Three-Dimensional; D008855:Microscopy, Electron, Scanning; D008867:Microtomy; D016613:Plastic Embedding; D020560:Proteobacteria / Q000145:classification / Q000378:metabolism / Q000648:ultrastructure*; D059467:Transcriptome
D004853:Epoxy Resins; C004875:EPON