Halobacterial Gas Vesicles. (A) Halobacterium salinarum colonies on a solid medium. Pink, opaque colonies from gas vesicle-containing cells; a red, transparent colony from gas vesicle-deficient cells. (B) Cryo-transmission electron micrograph of cells in 3 M NaCl plus 81 mM MgSO4. The image has the low signal-to-noise ratio due to the high concentration of NaCl. (C) Cryo-transmission electron micrograph of a focused ion beam-thinned cell in 3 M NaCl plus 81 mM MgSO4. The periodicity of the gas vesicle is clearly discerned. (A) Adapted from Pfeifer (2015), (B, C) from Bollschweiler et al. (2017), with permission from the publisher.
Gas vesicles, also known as gas vacuoles, are nanocompartments in certain prokaryotic organisms, which help in buoyancy.[1] Gas vesicles are composed entirely of protein; no lipids or carbohydrates have been detected.
