Halobacteriaceae
Encyclopedia
In taxonomy
, the Halobacteriaceae are a family
of the Halobacteriales
in the domain Archaea
.
s, though this name is also used for other organisms which live in somewhat less concentrated salt water. They are common in most environments where large amounts of salt, moisture, and organic material are available. Large blooms appear reddish, from the pigment bacteriorhodopsin
. This pigment is used to absorb light, which provides energy to create ATP
. Halobacteria also possess a second pigment, halorhodopsin
, which pumps in chloride ions in response to photons, creating a voltage gradient and assisting in the production of energy from light. The process is unrelated to other forms of photosynthesis
involving electron transport; however, and halobacteria are incapable of fixing carbon
from carbon dioxide
.
Halobacteria can exist in salty environments because although they are aerobes they have a separate and different way of creating energy through use of light energy. Parts of the membrane
s of halobacteria are purplish in color and containing retinal pigment
. This allows them to create a proton gradient across the membrane of the cell which can be used to create ATP
for their own use.
To live within their salty environments they have made certain adaptations. Their cellular machinery is adapted to high salt concentrations by having charged amino acids on their surfaces, allowing the cell to keep its water molecules around these components. They use the osmotic pressure and these amino acids to control the amount of salt within the cell. Also there are proteins inside of the cell that help to keep it alive in its environment. However, because of these adaptations if the cell were to be taken out of its natural salty environment it would most likely immediately burst from the osmotic pressure.
Alpha taxonomy
Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and...
, the Halobacteriaceae are a family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
of the Halobacteriales
Halobacteriales
In taxonomy, the Halobacteriales are an order of the Halobacteria, found in water saturated or nearly saturated with salt. They are also called halophiles, though this name is also used for other organisms which live in somewhat less concentrated salt water. They are common in most environments...
in the domain Archaea
Archaea
The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon...
.
Overview
Halobacteriaceae are found in water saturated or nearly saturated with salt. They are also called halophileHalophile
Halophiles are extremophile organisms that thrive in environments with very high concentrations of salt. The name comes from the Greek for "salt-loving". While the term is perhaps most often applied to some halophiles classified into the Archaea domain, there are also bacterial halophiles and some...
s, though this name is also used for other organisms which live in somewhat less concentrated salt water. They are common in most environments where large amounts of salt, moisture, and organic material are available. Large blooms appear reddish, from the pigment bacteriorhodopsin
Bacteriorhodopsin
Bacteriorhodopsin is a protein used by Archaea, the most notable one being Halobacteria. It acts as a proton pump; that is, it captures light energy and uses it to move protons across the membrane out of the cell...
. This pigment is used to absorb light, which provides energy to create ATP
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
. Halobacteria also possess a second pigment, halorhodopsin
Halorhodopsin
Halorhodopsin is a light-driven ion pump, specific for chloride ions, and found in phylogenetically ancient archaea, known as halobacteria...
, which pumps in chloride ions in response to photons, creating a voltage gradient and assisting in the production of energy from light. The process is unrelated to other forms of photosynthesis
Photosynthesis
Photosynthesis is a chemical process that converts carbon dioxide into organic compounds, especially sugars, using the energy from sunlight. Photosynthesis occurs in plants, algae, and many species of bacteria, but not in archaea. Photosynthetic organisms are called photoautotrophs, since they can...
involving electron transport; however, and halobacteria are incapable of fixing carbon
Carbon fixation
In biology, carbon fixation is the reduction of carbon dioxide to organic compounds by living organisms. The obvious example is photosynthesis. Carbon fixation requires both a source of energy such as sunlight, and an electron donor such as water. All life depends on fixed carbon. Organisms that...
from carbon dioxide
Carbon dioxide
Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...
.
Halobacteria can exist in salty environments because although they are aerobes they have a separate and different way of creating energy through use of light energy. Parts of the membrane
Biological membrane
A biological membrane or biomembrane is an enclosing or separatingmembrane that acts as a selective barrier, within or around a cell. It consists of a lipid bilayer with embedded proteins that may constitute close to 50% of membrane content...
s of halobacteria are purplish in color and containing retinal pigment
Pigment
A pigment is a material that changes the color of reflected or transmitted light as the result of wavelength-selective absorption. This physical process differs from fluorescence, phosphorescence, and other forms of luminescence, in which a material emits light.Many materials selectively absorb...
. This allows them to create a proton gradient across the membrane of the cell which can be used to create ATP
Adenosine triphosphate
Adenosine-5'-triphosphate is a multifunctional nucleoside triphosphate used in cells as a coenzyme. It is often called the "molecular unit of currency" of intracellular energy transfer. ATP transports chemical energy within cells for metabolism...
for their own use.
To live within their salty environments they have made certain adaptations. Their cellular machinery is adapted to high salt concentrations by having charged amino acids on their surfaces, allowing the cell to keep its water molecules around these components. They use the osmotic pressure and these amino acids to control the amount of salt within the cell. Also there are proteins inside of the cell that help to keep it alive in its environment. However, because of these adaptations if the cell were to be taken out of its natural salty environment it would most likely immediately burst from the osmotic pressure.