Archaeoglobus is a genus of the phylum Euryarchaeota

Euryarchaeota

In the taxonomy of microorganisms, the Euryarchaeota are a phylum of the Archaea.The Euryarchaeota include the methanogens, which produce methane and are often found in intestines, the halobacteria, which survive extreme concentrations of salt, and some extremely thermophilic aerobes and anaerobes...

. Archaeoglobus can be found in high-temperature oil fields where they may contribute to oil field souring.

Metabolism

Archaeoglobus grow at extremely high temperatures between 60 and 95 °C, with optimal growth at 83 °C (ssp. A. fulgidus VC-16). They are sulfate-reducing

Sulfate-reducing bacteria

Sulfate-reducing bacteria are those bacteria and archaea that can obtain energy by oxidizing organic compounds or molecular hydrogen while reducing sulfate to hydrogen sulfide...

 archaea

Archaea

The Archaea are a group of single-celled microorganisms. A single individual or species from this domain is called an archaeon...

, coupling the reduction of sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 to sulfide

Sulfide

A sulfide is an anion of sulfur in its lowest oxidation state of 2-. Sulfide is also a slightly archaic term for thioethers, a common type of organosulfur compound that are well known for their bad odors.- Properties :...

 with the oxidation of many different organic carbon sources, including complex polymers.

A. lithotrophicus live chemolitho-autotrophically

Lithoautotroph

A lithoautotroph is a microbe which derives energy from reduced compounds of mineral origin. They may also be referred to as chemolithoautotrophs, a type of lithotrophs, reflecting their autotrophic metabolic pathways. Lithoautotrophs are exclusively microbes; macrofauna do not possess the...

 from hydrogen

Hydrogen

Hydrogen is the chemical element with atomic number 1. It is represented by the symbol H. With an average atomic weight of , hydrogen is the lightest and most abundant chemical element, constituting roughly 75% of the Universe's chemical elemental mass. Stars in the main sequence are mainly...

, sulfate

Sulfate

In inorganic chemistry, a sulfate is a salt of sulfuric acid.-Chemical properties:...

 and carbon dioxide

Carbon dioxide

Carbon dioxide is a naturally occurring chemical compound composed of two oxygen atoms covalently bonded to a single carbon atom...

. Also A. profundus grow lithotroph

Lithotroph

A lithotroph is an organism that uses an inorganic substrate to obtain reducing equivalents for use in biosynthesis or energy conservation via aerobic or anaerobic respiration. Known chemolithotrophs are exclusively microbes; No known macrofauna possesses the ability to utilize inorganic...

ically, but while this species needs acetate

Acetate

An acetate is a derivative of acetic acid. This term includes salts and esters, as well as the anion found in solution. Most of the approximately 5 billion kilograms of acetic acid produced annually in industry are used in the production of acetates, which usually take the form of polymers. In...

 and CO₂ for biosynthesis

Biosynthesis

Biosynthesis is an enzyme-catalyzed process in cells of living organisms by which substrates are converted to more complex products. The biosynthesis process often consists of several enzymatic steps in which the product of one step is used as substrate in the following step...

 they are heterotroph

Heterotroph

A heterotroph is an organism that cannot fix carbon and uses organic carbon for growth. This contrasts with autotrophs, such as plants and algae, which can use energy from sunlight or inorganic compounds to produce organic compounds such as carbohydrates, fats, and proteins from inorganic carbon...

.

The complete A. fulgidus genome sequence revealed the presence of a nearly complete set of genes for methanogenesis

Methanogenesis

Methanogenesis or biomethanation is the formation of methane by microbes known as methanogens. Organisms capable of producing methane have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with...

. The function of these genes in A. fulgidus remains unknown, while the lack of the enzyme methyl-CoM reductase does not allow for methanogenesis

Methanogenesis

Methanogenesis or biomethanation is the formation of methane by microbes known as methanogens. Organisms capable of producing methane have been identified only from the domain Archaea, a group phylogenetically distinct from both eukaryotes and bacteria, although many live in close association with...

 to occur by a mechanism similar to that found in other methanogen

Methanogen

Methanogens are microorganisms that produce methane as a metabolic byproduct in anoxic conditions. They are classified as archaea, a group quite distinct from bacteria...

s.

Description and Significance

Archaeoglobus members are hyperthermophiles that can be found in hydrothermal vents, oil deposits, and hot springs. They can produce biofilm

Biofilm

A biofilm is an aggregate of microorganisms in which cells adhere to each other on a surface. These adherent cells are frequently embedded within a self-produced matrix of extracellular polymeric substance...

when subjected to environmental stresses such as extreme pH or temperature, high concentrations of metal, or the addition of antibiotics, xenobiotics, or oxygen. These archaeons are known to cause the corrosion of iron and steel in oil and gas processing systems by producing iron sulphide. Their bioflims, however, may have industrial or research applications in the form of detoxifying metal contaminated samples or to gather metals in an economically recoverable form.

Genome Structure

The Archaeoglobus fulgidus genome is a circular chromosome roughly half the size of E. coli at 2,178,000 base pairs. A quarter of the genome encodes preserved proteins whose functions are not yet determined, but are expressed in other archaeons such as Methanococcus jannaschii. Another quarter encodes proteins unique to the archaeal domain. One observation about the genome is that there are many gene duplications and the duplicated proteins are not identical. This suggests metabolic differentiation specifically with respect to the decomposing and recycling carbon pathways through scavenged fatty acids. The duplicated genes also gives the genome a larger genome size than its fellow archaeon M. jannaschii. It is also noted that Archaeoglobus contained no inteins in coding regions where M. jannaschii had 18.

Ecology

Archaeoglobus species utilize their environment by acting as scavengers with many potential carbon sources. They can obtain carbon from fatty acids, the degradation of amino acids, aldehydes, organic acids, and possibly CO as well. Higher temperatures (approx. 83oC) are ideal growth temperatures for Archaeoglobus, although a biofilm environment provides some environmental elasticity. Biofilm is composed of polysaccharides, proteins, and metals.

Medicine

Cells protected by biofilm are difficult to destroy using conventional anti-microbial therapy, which gives them medicinal possibilities.

External links