''Methylacidiphilum infernorum '' is an extremely

acidophilic 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, including Archaea, Bacteria,Becker, A.Types of Bacteri ...

methanotroph Methanotrophs (sometimes called methanophiles) are prokaryotes that metabolize methane as their source of carbon and chemical energy. They are bacteria or archaea, can grow aerobically or anaerobically, and require single-carbon compounds to ...

aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cellu ...

bacteria first isolated and described in 2007 growing on soil and sediment on

Hell's Gate Hells Gate, Hell's Gate, Hell Gate or Hells Gates may refer to: Places Africa * Hell's Gate National Park, Kenya Antarctica * Hells Gate (Antarctica), Victoria Land * Hells Gate Moraine, Victoria Land Asia * Nyalam Town, Tibet * A location in N ...

New Zealand New Zealand () is an island country in the southwestern Pacific Ocean. It consists of two main landmasses—the North Island () and the South Island ()—and List of islands of New Zealand, over 600 smaller islands. It is the List of isla ...

. Similar organisms have also been isolated from geothermal sites on

Italy Italy, officially the Italian Republic, is a country in Southern Europe, Southern and Western Europe, Western Europe. It consists of Italian Peninsula, a peninsula that extends into the Mediterranean Sea, with the Alps on its northern land b ...

and

Russia Russia, or the Russian Federation, is a country spanning Eastern Europe and North Asia. It is the list of countries and dependencies by area, largest country in the world, and extends across Time in Russia, eleven time zones, sharing Borders ...

. A

polyextremophile An extremophile () is an organism that is able to live (or in some cases thrive) in extreme environments, i.e., environments with conditions approaching or stretching the limits of what known life can adapt to, such as extreme temperature, pres ...

, these non-motile rods grows optimally at pH between 2.0 and 2.5 and

temperature Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making ...

of 60 °C. It is a

ic obligated bacteria that grows at 25% (v/v) of

methane Methane ( , ) is a chemical compound with the chemical formula (one carbon atom bonded to four hydrogen atoms). It is a group-14 hydride, the simplest alkane, and the main constituent of natural gas. The abundance of methane on Earth makes ...

in air. It is also very dependent on

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 ...

concentrations to grow, optimally at 8% (v/v) in air. Due to its classification in the phylum ''

Verrucomicrobiota Verrucomicrobiota is a phylum of Gram-negative bacteria that contains only a few described species. The species identified have been isolated from fresh water, marine and soil environments and human faeces. A number of as-yet uncultivated species ...

'' and its extreme acidophilic phenotype ''M. infernorum'' is unique between all known methanotrophs.

Biology

Genome

It has a single circular chromosome of 2,287,145

base pairs A base pair (bp) is a fundamental unit of double-stranded nucleic acids consisting of two nucleobases bound to each other by hydrogen bonds. They form the building blocks of the DNA double helix and contribute to the folded structure of both DNA ...

. Under genome analysis it was found that ''M. infernorum'' may use a novel methylotrophic pathway because it encodes

methane monooxygenase Methane monooxygenase (MMO) is an enzyme capable of oxidizing the C-H bond in methane as well as other alkanes. Methane monooxygenase belongs to the class of oxidoreductase enzymes (). There are two forms of MMO: the well-studied soluble form (s ...

enzymes but lacks known genetic modules for methanol and formaldehyde oxidation. All the enzymes required for the Calvin Benson Bassham cycle were identify by genetic analysis.

Metabolism

It has been predicted that ''M. infernorum'' possess most of the key metabolic pathways for the biosynthesis of all amino acids, nucleotides and cofactors, with the sole exception of the

cobalamin Vitamin B12, also known as cobalamin, is a water-soluble vitamin involved in metabolism. One of eight B vitamins, it serves as a vital cofactor (biochemistry), cofactor in DNA synthesis and both fatty acid metabolism, fatty acid and amino a ...

cofactor. Genetic studies have shown that the enzymes it uses in several metabolic pathways differs to the ones used by other

methylotroph Methylotrophs are a diverse group of microorganisms that can use reduced one-carbon compounds, such as methanol or methane, as the carbon source for their growth; and multi-carbon compounds that contain no carbon-carbon bonds, such as dimethyl eth ...

s like for example in the biosynthesis of aromatic amino acids, lipoic acid biosynthesis,

urea cycle The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions that produces urea (NH2)2CO from ammonia (NH3). Animals that use this cycle, mainly amphibians and mammals, are called ureotelic. The urea cycle converts highl ...

and in the number and diversity of transporters encoded. The bacteria is able to counteract extreme acidic environments thanks to the presence of various enzymes like

glutamate decarboxylase Glutamate decarboxylase or glutamic acid decarboxylase (GAD) is an enzyme that catalyzes the Decarboxylation#Decarboxylation of amino acids, decarboxylation of glutamate to gamma-aminobutyric acid (GABA) and carbon dioxide (). GAD uses pyridoxal ...

, glutamate/γ-aminobutyrate antiporter, arginine decarboxylase and an arginine/agmatine antiporter.

References

External links

''Methylacidiphilum infernorum''
on HAMAT (High-quality Automated and Manual Annotation of Proteins) {{Taxonbar, from=Q29887872 Bacteria described in 2007 Verrucomicrobiota Polyextremophiles Candidatus taxa