Gas vesicle

In addition, gas vesicles can be used to maintain optimum salinity by positioning the organism in specific locations in a stratified body of water to prevent osmotic shock.

The ability to synthesize gas vesicles is one of many strategies that allow halophilic organisms to tolerate environments with high salt content.

[5] Although there is evidence suggesting the early evolution of gas vesicles, plasmid transfer serves as an alternate explanation of the widespread and conserved nature of the organelle.

It appears that gas vesicles begin their existence as small biconical (two cones with the flat bases joined) structures which enlarge to the specific diameter than grow and expand their length.

For Anabaena flos-aquae, higher light intensities leads to vesicle collapse from an increase in turgor pressure and greater accumulation of photosynthetic products.

Halobacterium salinarum produce little or no vesicles under anaerobic conditions due to reduced synthesis of mRNA transcripts encoding for Gvp proteins.

[13] Ultrasonic irradiation, at certain frequencies, was found to collapse gas vesicles in cyanobacteria Spirulina platensis, preventing them from blooming.

[5] This is advantageous to the organism as resources for gas vesicle production are utilized only when there is oxygen limitation caused by an increase in bacterial population.

Several characteristics of the protein encoded by the gas vesicle gene gvpC allow it to be used as carrier and adjuvant for antigens: it is stable, resistant to biological degradation, tolerates relatively high temperatures (up to 50 °C), and non-pathogenic to humans.

[16] Different genomic segments encoding for several Chlamydia trachomatis pathogen's proteins, including MOMP, OmcB, and PompD, are joined to the gvpC gene of Halobacteria.

[17] A similar experiment uses the same gas vesicle gene and Salmonella enterica pathogen's secreted inosine phosphate effector protein SopB4 and SopB5 to generate a potential vaccine vector.

Potential vaccines using gas vesicle as an antigen display can be given via the mucosal route as an alternative administration pathway, increasing its accessibility to more people and eliciting a wider range of immune responses within the body.

[20] Moreover, the ability of some gas vesicle shells to buckle generates harmonic ultrasound echoes that improves the contrast to tissue ratio.

[22] The ability to non-invasively collapse gas vesicles using pressure waves provides a mechanism for erasing their signal and improving their contrast.

Acoustic reporter genes provide sub-millimeter spatial resolution and a penetration depth of several centimeters, enabling the in vivo study of biological processes deep within the tissue.

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 MgSO 4 . 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 MgSO 4 . 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 imaged with transmission electron microscopy. (A) Wild-type cells. (B) Pressurized wild-type cells. (C) Mutant cells deleted for the gas vesicle gene clusters. (D) Gas vesicles with different widths. (A~D) Adapted from Ramsay et al. (2011), with permission from the publisher.
Gas vesicle formation and morphology. (A) and (B) Transmission electron micrographs of gas vesicles in Halobacterium salinarum. Spindle-shaped gas vesicles in (A). Isolated cylinder-shaped gas vesicles in (B). (C) Morphogenesis of gas vesicles from a bicone to a spindle- or cylinder-shaped gas vesicle. (D) Groups of gas vesicles. They form clusters during the early stage of gas vesicle formation, and fill the cells later. (E) Detailed diagram of a gas vesicle. A gas nanocompartment enclosed with a gas-permeable shell. (A~D) Adapted from Pfeifer (2012) and (E) from Shapiro et al. (2014), with permission from the publisher.
The Hammer Experiment