Halolamina
   HOME

TheInfoList



OR:

Halobacteriaceae is a
family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...
in the order
Halobacteriales 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. Th ...
and the domain
Archaea Archaea ( ) is a Domain (biology), domain of organisms. Traditionally, Archaea only included its Prokaryote, prokaryotic members, but this has since been found to be paraphyletic, as eukaryotes are known to have evolved from archaea. Even thou ...
. ''Halobacteriaceae'' represent a large part of
halophilic A halophile (from the Greek word for 'salt-loving') is an extremophile that thrives in high salt concentrations. In chemical terms, halophile refers to a Lewis acidic species that has some ability to extract halides from other chemical species. ...
Archaea, along with members in two other methanogenic families, ''Methanosarcinaceae'' and ''Methanocalculaceae''. The family consists of many diverse genera that can survive extreme environmental niches. Most commonly, Halobacteriaceae are found in hypersaline lakes and can even tolerate sites polluted by heavy metals. They include
neutrophile A neutrophile is a neutrophilic organism that thrives in a neutral pH environment between 6.5 and 7.5. Environment The pH of the environment can support growth or hinder neutrophilic organisms. When the pH is within the microbe's range, they g ...
s,
acidophile Acidophiles or acidophilic organisms are those that thrive under highly acidic conditions (usually at pH 5.0 or below). These organisms can be found in different branches of the Tree of life (biology), tree of life, including Archaea, Bacteria,Bec ...
s (ex. ''Halarchaeum acidiphilum''),
alkaliphile Alkaliphiles are a class of extremophilic microbes capable of survival in alkaline ( pH roughly 8.5–11) environments, growing optimally around a pH of 10. These bacteria can be further categorized as obligate alkaliphiles (those that require hig ...
s (ex. ''
Natronobacterium ''Natronobacterium'' is a genus of archaeans in the family the Natrialbaceae.See the NCBIbr>webpage on Natronobacterium Data extracted from the A member of the domain Archaea, it is both an extreme halophile and alkaliphile, thriving at an op ...
''), and there have even been
psychrotolerant Psychrophiles or cryophiles (adj. ''psychrophilic'' or ''cryophilic'') are extremophilic organisms that are capable of growth and reproduction in low temperatures, ranging from to . They are found in places that are permanently cold, such as the ...
species discovered (ex. ''Hrr. lacusprofundi''). Some members have been known to live aerobically, as well as anaerobically, and they come in many different morphologies. These diverse morphologies include rods in genus
Halobacterium ''Halobacterium'' (common abbreviation ''Hbt.'') is a genus in the family Halobacteriaceae. The genus ''Halobacterium'' ("salt" or "ocean bacterium") consists of several species of Archaea with an aerobic metabolism which requires an environm ...
, cocci in
Halococcus ''Halococcus'' (common abbreviation: ''Hcc.'') is a genus of archaeans in the family Halococcaceae. Ecology ''Halococcus'' is a genus of extreme halophilic archaea, meaning that they require high salt levels, sometimes as high as 32% NaCl, ...
, flattened discs or cups in
Haloferax ''Haloferax'' (common abbreviation: ''Hfx.'') is a genus of halobacteria in the order Haloferacaceae. Genetic exchange Cells of ''H. mediterranei'' and cells of the related species '' H. volcanii'' can undergo a process of genetic exchange betw ...
, and other shapes ranging from flattened triangles in
Haloarcula ''Haloarcula'' (common abbreviation ''Har.'') is a genus of extreme halophilic Archaeon, Archaea in the class of Halobacteria. Cell structure ''Haloarcula'' species can be distinguished from other genera in the family Halobacteriaceae by the pre ...
to squares in
Haloquadratum ''Haloquadratum'' (common abbreviation: ''Hqr.'') is a genus of archaean, belonging to the family Haloferacaceae. The first species to be identified in this group, ''Haloquadratum walsbyi'', is unusual in that its cells are shaped like square, ...
, and
Natronorubrum ''Natronorubrum'' is a genus of archaeans in the family Halobacteriaceae. Phylogeny The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information ...
. Most species of Halobacteriaceae are best known for their high salt tolerance and red-pink pigmented members (due to bacterioruberin carotenoids), but there are also non-pigmented species and those that require moderate salt conditions. Some species of Halobacteriaceae have been shown to exhibit phosphorus solubilizing activities that contribute to phosphorus cycling in hypersaline environments. Techniques such as 16S rRNA analysis and
DNA–DNA hybridization In genomics, DNA–DNA hybridization is a molecular biology technique that measures the degree of genetic similarity between DNA sequences. It is used to determine the genetic distance between two organisms and has been used extensively in phylo ...
have been major contributors to taxonomic classification in Halobacteriaceae, partly due to the difficulty in culturing halophilic Archaea.


Overview

Halobacteriaceae are found in water saturated or nearly saturated with salt. They are also called
halophile A halophile (from the Greek word for 'salt-loving') is an extremophile that thrives in high salt In common usage, salt is a mineral composed primarily of sodium chloride (NaCl). When used in food, especially in granulated form, it is more ...
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 (Bop) is a protein used by Archaea, most notably by Haloarchaea, a class of the Euryarchaeota. 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. The res ...
. This pigment is used to absorb light, which provides energy to create ATP. Halobacteria also possess a second pigment,
halorhodopsin Halorhodopsin is a seven-transmembrane retinylidene protein from microbial rhodopsin family. It is a chloride-specific light-activated ion pump found in archaea known as halobacteria. It is activated by green light wavelengths of approximatel ...
, 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 ( ) is a system of biological processes by which photosynthetic organisms, such as most plants, algae, and cyanobacteria, convert light energy, typically from sunlight, into the chemical energy necessary to fuel their metabo ...
involving electron transport and halobacteria are incapable of fixing carbon from
carbon dioxide Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
. Halobacteria can exist in salty environments because although they are
aerobes An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment. The ability to exhibit aerobic respiration may yield benefits to the aerobic organism, as aerobic respiration yields more energy than anaerobic ...
, they have a separate and different way of creating energy through use of light energy. Parts of the
membrane A membrane is a selective barrier; it allows some things to pass through but stops others. Such things may be molecules, ions, or other small particles. Membranes can be generally classified into synthetic membranes and biological membranes. Bi ...
s of halobacteria are purplish in color and contain retinal
pigment A pigment is a powder used to add or alter color or change visual appearance. Pigments are completely or nearly solubility, insoluble and reactivity (chemistry), chemically unreactive in water or another medium; in contrast, dyes are colored sub ...
. This allows them to create a
proton gradient An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two parts: * The chemical gradient, or difference in solute concentration across a membrane. ...
across the membrane of the cell which can be used to create ATP for their own use. They have certain adaptations to live within their salty environments. For example, 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. The osmotic pressure and these amino acids help to control the amount of salt within the cell. However, because of these adaptations, if the cell is placed in a wet, less salty environment, it is likely to immediately burst from the osmotic pressure.


Phylogeny

The currently accepted taxonomy is based on the
List of Prokaryotic names with Standing in Nomenclature List of Prokaryotic names with Standing in Nomenclature (LPSN) is an online database that maintains information on the naming and taxonomy of prokaryotes, following the taxonomy requirements and rulings of the International Code of Nomenclatu ...
(LPSN) and
National Center for Biotechnology Information The National Center for Biotechnology Information (NCBI) is part of the National Library of Medicine (NLM), a branch of the National Institutes of Health (NIH). It is approved and funded by the government of the United States. The NCBI is lo ...
(NCBI). Note 1: * polyphyletic Halobacteriaceae
Note 2: Unassigned Halobacteriaceae * '' Actinoarchaeum'' corrig. Tang et al. 2024 * "'' Haloalcalophilium''" Lizama et al. 2000a * '' Halospeciosus'' Li et al. 2024


See also

*
List of Archaea genera This article lists the genera of the Archaea. The currently accepted taxonomy is based on the List of Prokaryotic names with Standing in Nomenclature (LPSN) and National Center for Biotechnology Information (NCBI). However, in the List provided bel ...


References


Further reading


Scientific journals

* * * *


Scientific books

* * *


External links


Correct names of taxa within the family ''Halobacteriaceae''
{{Taxonbar, from=Q764133 Archaea taxonomic families Euryarchaeota