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Haloarchaea and the formation of gas vesicles.

Pfeifer F - Life (Basel) (2015)

Bottom Line: Halophilic Archaea (Haloarchaea) thrive in salterns containing sodium chloride concentrations up to saturation.Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration.Except for GvpI and GvpH, all of these are required to form the gas permeable wall.

View Article: PubMed Central - PubMed

Affiliation: Microbiology and Archaea, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany. pfeifer@bio.tu-darmstadt.de.

ABSTRACT
Halophilic Archaea (Haloarchaea) thrive in salterns containing sodium chloride concentrations up to saturation. Many Haloarchaea possess genes encoding gas vesicles, but only a few species, such as Halobacterium salinarum and Haloferax mediterranei, produce these gas-filled, proteinaceous nanocompartments. Gas vesicles increase the buoyancy of cells and enable them to migrate vertically in the water body to regions with optimal conditions. Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration. Fourteen gas vesicle protein (gvp) genes are involved in their formation, and regulation of gvp gene expression occurs at the level of transcription, including the two regulatory proteins, GvpD and GvpE, but also at the level of translation. The gas vesicle wall is solely formed of proteins with the two major components, GvpA and GvpC, and seven additional accessory proteins are also involved. Except for GvpI and GvpH, all of these are required to form the gas permeable wall. The applications of gas vesicles include their use as an antigen presenter for viral or pathogen proteins, but also as a stable ultrasonic reporter for biomedical purposes.

No MeSH data available.


Related in: MedlinePlus

Colonies (a) and cells of Halobacterium (Hbt.) salinarum producing gas vesicles (b,c). (a) Colonies on solid media grown for one week at 40 °C and three weeks at room temperature. Vesicle (Vac+) cells form pink white colonies, whereas colonies of Vac− mutants are red and transparent. (b) Cells grown in liquid media observed by phase-contrast light microscopy. (c) Cells of a Vac+ colony investigated by transmission electron microscopy. The pleomorphic shape of the cells grown for three months on solid media differs from the rod-shaped cells seen in liquid culture.
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life-05-00385-f001: Colonies (a) and cells of Halobacterium (Hbt.) salinarum producing gas vesicles (b,c). (a) Colonies on solid media grown for one week at 40 °C and three weeks at room temperature. Vesicle (Vac+) cells form pink white colonies, whereas colonies of Vac− mutants are red and transparent. (b) Cells grown in liquid media observed by phase-contrast light microscopy. (c) Cells of a Vac+ colony investigated by transmission electron microscopy. The pleomorphic shape of the cells grown for three months on solid media differs from the rod-shaped cells seen in liquid culture.

Mentions: The first haloarchaeon characterized in the laboratory was Halobacterium (Hbt.) salinarum (formerly Hbt. halobium), isolated as a contaminant from salted fish in 1919 [3]. All other Haloarchaea derive from salt lakes, salt flats or solar salterns. Hbt. salinarum uses light-driven ion pumps (proton pump: bacteriorhodopsin; chloride pump: halorhodopsin; plus sensory rhodopsins) as special energy conversion and sensing systems, and similar light-driven proton pumps are also present in marine proteobacteria [4,5]. Bacteriorhodopsin is produced under microaerobic conditions and forms almost crystalline purple patches in the cytoplasmic membrane of Hbt. salinarum (purple membrane, Pum). Haloarchaea also contain C50 carotenoids (bacterioruberins, Rub) leading to red colonies on agar plates. The possession of gas vesicles (Vac) turns the colony color into pink and opaque, as opposed to the red transparent colonies of Vac− mutants (Figure 1a). Blooms and biofilms of Haloarchaea color brines and salt lakes red, as also seen for solar salterns at the coastline. Since Haloarchaea captured in salt crystals survive for a very long time, the use of natural sea salt was the reason why Hbt. salinarum grew on salted fish.


Haloarchaea and the formation of gas vesicles.

Pfeifer F - Life (Basel) (2015)

Colonies (a) and cells of Halobacterium (Hbt.) salinarum producing gas vesicles (b,c). (a) Colonies on solid media grown for one week at 40 °C and three weeks at room temperature. Vesicle (Vac+) cells form pink white colonies, whereas colonies of Vac− mutants are red and transparent. (b) Cells grown in liquid media observed by phase-contrast light microscopy. (c) Cells of a Vac+ colony investigated by transmission electron microscopy. The pleomorphic shape of the cells grown for three months on solid media differs from the rod-shaped cells seen in liquid culture.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4390858&req=5

life-05-00385-f001: Colonies (a) and cells of Halobacterium (Hbt.) salinarum producing gas vesicles (b,c). (a) Colonies on solid media grown for one week at 40 °C and three weeks at room temperature. Vesicle (Vac+) cells form pink white colonies, whereas colonies of Vac− mutants are red and transparent. (b) Cells grown in liquid media observed by phase-contrast light microscopy. (c) Cells of a Vac+ colony investigated by transmission electron microscopy. The pleomorphic shape of the cells grown for three months on solid media differs from the rod-shaped cells seen in liquid culture.
Mentions: The first haloarchaeon characterized in the laboratory was Halobacterium (Hbt.) salinarum (formerly Hbt. halobium), isolated as a contaminant from salted fish in 1919 [3]. All other Haloarchaea derive from salt lakes, salt flats or solar salterns. Hbt. salinarum uses light-driven ion pumps (proton pump: bacteriorhodopsin; chloride pump: halorhodopsin; plus sensory rhodopsins) as special energy conversion and sensing systems, and similar light-driven proton pumps are also present in marine proteobacteria [4,5]. Bacteriorhodopsin is produced under microaerobic conditions and forms almost crystalline purple patches in the cytoplasmic membrane of Hbt. salinarum (purple membrane, Pum). Haloarchaea also contain C50 carotenoids (bacterioruberins, Rub) leading to red colonies on agar plates. The possession of gas vesicles (Vac) turns the colony color into pink and opaque, as opposed to the red transparent colonies of Vac− mutants (Figure 1a). Blooms and biofilms of Haloarchaea color brines and salt lakes red, as also seen for solar salterns at the coastline. Since Haloarchaea captured in salt crystals survive for a very long time, the use of natural sea salt was the reason why Hbt. salinarum grew on salted fish.

Bottom Line: Halophilic Archaea (Haloarchaea) thrive in salterns containing sodium chloride concentrations up to saturation.Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration.Except for GvpI and GvpH, all of these are required to form the gas permeable wall.

View Article: PubMed Central - PubMed

Affiliation: Microbiology and Archaea, Department of Biology, Technische Universität Darmstadt, Schnittspahnstrasse 10, 64287 Darmstadt, Germany. pfeifer@bio.tu-darmstadt.de.

ABSTRACT
Halophilic Archaea (Haloarchaea) thrive in salterns containing sodium chloride concentrations up to saturation. Many Haloarchaea possess genes encoding gas vesicles, but only a few species, such as Halobacterium salinarum and Haloferax mediterranei, produce these gas-filled, proteinaceous nanocompartments. Gas vesicles increase the buoyancy of cells and enable them to migrate vertically in the water body to regions with optimal conditions. Their synthesis depends on environmental factors, such as light, oxygen supply, temperature and salt concentration. Fourteen gas vesicle protein (gvp) genes are involved in their formation, and regulation of gvp gene expression occurs at the level of transcription, including the two regulatory proteins, GvpD and GvpE, but also at the level of translation. The gas vesicle wall is solely formed of proteins with the two major components, GvpA and GvpC, and seven additional accessory proteins are also involved. Except for GvpI and GvpH, all of these are required to form the gas permeable wall. The applications of gas vesicles include their use as an antigen presenter for viral or pathogen proteins, but also as a stable ultrasonic reporter for biomedical purposes.

No MeSH data available.


Related in: MedlinePlus