GAS VESICLES IN BACTERIA

 GAS VACUOLES

·       Gas vacuole, a structure that provides buoyancy to some aquatic Prokaryotes.

·       Gas vacuoles are present in many Photosynthetic bacteria and a few other Aquatic prokaryotes such as Halobacterium (a salt-loving archaeon) and Thiothrix (a filamentous bacterium).

GAS VESICLES

·       Gas vacuoles are aggregates of enormous numbers of Small, Hollow, Cylindrical or Conical shaped structures called Gas vesicles.

·       Gas vesicles in different species vary in length from about 300 to more than 1000 nm and in width from 45 to 120 nm.

·       Gas vesicles may number from a few to hundreds per cell.

·       Gas vesicle walls are composed entirely of two small Protein sub-units (Major protein – Gvp A and Minor protein – Gvp C). These protein sub-units assemble to form a rigid enclosed cylinder that is hollow and impermeable to water but freely permeable to atmospheric gases.

Functions of Gas Vesicles

·       Aquatic Prokaryotes with Gas vesicles can regulate their buoyancy to float at the depth necessary for proper a) Light intensity; b) Oxygen concentration and c) Nutrient levels.

·       Phototrophic aquatic prokaryotes in particular can benefit from Gas vesicles because they allow cells to adjust their vertical position in a water column to sink or rise to regions where conditions (for example, Light intensity) are optimal for Photosynthesis.

·       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.