Definition, Structure, and Functions
Biology is a fascinating science. It helps us learn about the living world around us as well as our bodies. The living world around us contains phenomenal details and characteristics specific to each organism. From humans, mammals, to single-celled organisms, we can study the fascinating lives of these organisms through Biology.
One will be stunned to know how the tiniest structures can help give an organism its particular features. In this article today, we will learn about gas vacuoles also known as gas vesicles in certain bacteria.
These gas vacuoles are a characteristic feature of many prokaryotic organisms like aquatic bacteria.
As you read on, you will understand the structure of these gas vacuoles, their functions, their growth, and how they help these organisms stay afloat in water. You will also study their unique role in vaccine development.
What are Gas Vacuoles that State their Functions?
Gas vesicles, also termed gas vacuoles, are nano compartments that assist in buoyancy in some prokaryotic species. Gas vesicles are largely protein composed; no lipids and carbohydrates are being reported.
Gas vacuoles found in prokaryotes are air-filled and are like cylindrical compartments. They assist in the buoyancy process.
Gas vacuoles are found in many marine bacteria, including cyanobacteria or blue-green algae, halophilic archaea, and green bacteria.
Gas Vacuole Structure
An accumulation of several gas vesicles is gas vacuoles. In different species, the form and distribution of gas vesicles vary. Gas vesicles are large and construct parallel bundles in cyanobacteria, while in purple sulfur bacteria, they are smaller and irregularly distributed.
Protein-bound structures are gas vacuoles. A protein membrane covers each gas vesicle.
The vesicle's inner portion is hydrophobic, so it does not allow water to enter.
Gas vesicles have a diameter of about 75 nm and a length ranging from 200 to 1000 nm.
Regulation of Gas Vacuole Formation-
Proteins and extracellular environmental factors control gas vesicle synthesis.
Greater intensity of lights leads to inhibition of gas vesicle synthesis. In Anabaena, good light intensity collapses gas vesicles caused by the accumulation of higher turgor strain and photosynthetic products. Exposure to the high intensity of light on the ground may also affect the bacterial genome.
Gas vesicle synthesis is also controlled by the amount of oxygen. In halophilic archaea, oxygen deprivation prevents vesicle formation.
Carbohydrate accumulation reduces vesicle synthesis.
Increased environmental pH results in an increase in vesicle production in certain animals.
Function
In aquatic species, gas vesicles typically occur as they are used to attenuate the buoyancy of the cell and adjust the location of the cell in the water column so that it can be optimally positioned for photosynthesis or transfer to places with somewhat oxygen.
Other aerobes which do not grow in a water column by using oxygen at the top are competing with species that might float out into the air-liquid interface.
In particular, by placing the organism in particular positions in a stratified water body to avoid osmotic shock, gas vesicles could be used to preserve maximum salinity. Large solute concentrations can cause osmosis to pull water out of the cell, leading to cell lysis.
To raise the formation of vesicles in Microcystis organisms, an increased extracellular pH supply is expected. GvpA and gvpC transcript levels increase during increased pH, leading to greater exposure to ribosomes for expression and contributing to the upregulation of Gvp proteins. The higher transcription of these genes, the greater stability of mRNA, or the reduced degradation of the synthesized transcripts can be attributed to it.
Growth
Gas vesicles tend to begin their life as tiny biconical structures (two cones linked along with the flat bases) that expand to the specific diameter then develop and extend their length. Exactly what regulates the diameter is unclear, but that might be a molecule that interferes with GvpA, but it may also alter the form of GvpA.
Regulation
Two Gvp proteins control the formation of gas vesicles: GvpD, which prevents the expression from the proteins GvpA and GvpC, and the protein GvpE induces expression Vesicle formation is also influenced by extracellular environmental variables, either by regulating the development of Gvp protein or by directly disrupting the structure of the vesicle.
Role in Vaccine Development
The gvpC gaseous vesicle gene from Halobacterium sp. is majorly preferred as a delivery method for research on vaccines.
Many protein properties encoded by the gvpC gas vesicle gene enable it to be seen as an antigen carrier and adjuvant. It is prone to microbial breakdown, stable, tolerate significantly higher temperatures (up to 50 °C), and is anti-pathogenic to humans.
To build subunit vaccines with immunologic responses which can last for a longer period multiple antigens from different human pathogens have been consolidated into the gvpC gene.
The gvpC gene of Halobacteria is based on various genomic fragments coding for many proteins of the Chlamydia trachomatis pathogen, including OmcB, MOMP, and PompD. In vitro cell assessments demonstrate the expression of the Chlamydia genes on target cells by imagining strategies and demonstrate characteristic immunological responses including the activity of TLRs and the development of pro-inflammatory cytokines.
It is possible to use the gas vesicle gene as a delivery vehicle to produce a future Chlamydia vaccine. This method's drawbacks include the need to reduce the harm of the GvpC protein itself while integrating as many of the target genes of the vaccine into the section of the gvpC gene.
As can be seen, gas vacuoles are extremely integral to the survival of many prokaryotic organisms. Scientists believe these structures to be one of the oldest structures that have contributed to the survival of many organisms. As has been previously mentioned, these gas vacuoles have also played a crucial role in vaccine development. Much research has been done on these structures and they continue to be studied. Students must therefore understand this topic thoroughly. A deep look into the topic of gas vacuoles or gas vesicles helps us understand how nature has evolved to provide organisms with the most suited structure required for their survival.
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FAQs on Gas Vacuole
1. Why are Gas Vacuoles called So?
The gas vacuoles are called so due to the aggregates of hollow cylindrical structures called gas vesicles. In certain bacteria, they are found within. A membrane that is found to be permeable to gas tends to bind each gas vesicle. Buoyancy is created by inflation and deflation of the vesicles, enabling the bacterium to float in the water at the desired depth. Since the permeability of gas plays an important part in these hollow structures to maintain the organisms' buoyancy, they call gas vacuoles.
2. Are Gas Vacuoles surrounded by any Kind of Membrane?
The gas vacuoles are found to be surrounded by a membrane named tonoplast and it is observed that this membrane is permeable to gas. Gas vacuoles are found in just prokaryotic microorganisms, which may include bacteria and blue-green algae, so basically gas vacuoles in bacteria. This membrane is impermeable to water and thus contributes to the buoyancy of the organisms that they are found in.
3. How do Gas Vacuoles help Bacteria to float?
Gas vacuoles are nothing but groups of gas vesicles that are present in many bacteria like cyanobacteria. These vesicles resemble hollow cylinders that allow air to get inside them. Due to a membrane present around these vesicles that permits the entry and exit of gases, these bacteria get the buoyancy required to float. These gas vesicles continuously undergo inflation and deflation to get the desired buoyancy which helps them float at any desired depth in water.
4. Why do Gas Vacuoles have Membranes?
Gas vacuoles are surrounded by a protein membrane to serve several useful functions. The membrane allows the photosynthetic bacteria to receive optimal light. Since the membrane is permeable to air, it allows the required amount of oxygen in. The structure of gas vacuoles is such that it contributes to their coordinated movement with light. Since these membranes are impermeable to water, they help in regulating salinity within the bacteria and survive extreme conditions as well.
5. How to study Gas Vacuoles in detail?
Vedantu provides a detailed overview of a large number of topics in all subjects. Students can refer to topics related to gas vacuoles and bacteria on Vedantu's Biology page. They will be able to find important topics like Blue-green algae(Cynobecteria) and Vacuoles and their functions. In addition to this, they can find several other Biology topics explained by our expert teachers for ease of our students. In case students still need further clarification, they can refer to regular live sessions offered by Vedantu's mentors or opt for personalized tuitions for help in their studies.
