Crateriform structure of anaerobic ammonium-oxidizing bacteria

Abstract:

Anaerobic ammonium oxidation (anammox) is an important reaction in microbiology, geology, and environmental science, and anaerobic ammonium-oxidizing bacteria (AnAOB) are usually regarded as the driver of anammox. Demonstrating the biological characteristics of AnAOB is a vital issue for the application of anammox. Crateriform structure is a special microstructure and has been identified as one of the key features of AnAOB. However, little is known about the crateriform structure of AnAOB due to the failure to isolate AnAOB. In this study, the research advances about the crateriform structure of AnAOB and Planctomycetes were reviewed in terms of morphological characteristics, physiological functions, and ecological effects. Conclusions can be drawn as follows: (1) The crateriform structure of AnAOB is uniformly distributed over the cell surface, with a diameter of about 5 nm. (2) The crateriform structure of AnAOB may connect cytoplasmic membrane, outer membrane, and anammoxosome membrane, and play a role in substrate transport. (3) The crateriform structure has genetic stability, and its formation may be related to flagellum degeneration. (4) The crateriform structure may serve to maintain the niche stability of AnAOB by promoting material exchange and communication between microorganisms.