Methylophaga muralis

This species was discovered in scrapings from deteriorating marble monuments in the crypts of the Moscow Kremlin.[2][3] It was originally named M. murata in its 2005 species description by Russian Academy of Sciences microbiologist Yury Alexandrovich Trotsenko and colleagues,[2] but was renamed in 2011 to M. muralis.[1][4] The type strain, Kr3, was deposited in the All-Russia Collection of Microorganisms (VKM) and the National Collection of Industrial and Marine Bacteria (NCIMB) culture collections.[2]

The specific epithet muralis is a Latin adjective meaning "of or belonging to a wall".[1][5] Its original specific epithet, murata, means "surrounded by walls".[6]

The type strain Kr3 was extracted in Moscow from marble with a pH of 9.1.[2] M. muralis is an example of an endolith, being able to live on rock.[7] Another strain, named Bur 1, was isolated from a soda lake in Khilganta, Buryatia, Russia.[8][9]

The bacteria grows in temperatures of 0–42 °C (32–108 °F), a pH of 6–11, and a sodium chloride concentration of 0.05–3 moles per liter; although the optimal habitat is a temperature of 20–32 °C (68–90 °F), a pH of 8–9, and a sodium chloride concentration of 0.5–1.5 mol/L. It can survive being heated to 70 °C (158 °F), being frozen, or being freeze-dried. As this species is adapted to saline and alkaline environments, it is considered both halophilic and alkaliphilic.[2]

M. muralis cells are rod-shaped, with a width of 0.7 µm and a length of 1.7–2.0 µm. Each cell has a flagellum at one of its poles.[2]

This species is methylotrophic, meaning it can utilize carbon from one-carbon molecules like methanol and methylamine, although it also obtains carbon from trimethylamine, and fructose. It is an aerobic organism; in addition to requiring oxygen, it also needs vitamin B₁₂ and sodium ions to grow. It is gram-negative, like all Pseudomonadota. Reproduction is done via binary fission; it does not make spores.[2]

Its main fatty acids are palmitic acid, palmitoleic acid, and octadecanoic acid. The main phospholipids are phosphatidylethanolamine, phosphatidylglycerol, and cardiolipin.[2] Ectoine, glutamate, and, to a lesser extent, sucrose act as osmoprotectants.[2]

Plymouth University microbiologist Rich Boden, using the Tamura–Nei model, has argued on the basis of 16S ribosomal RNA that M. muralis, M. alcalica, and M. lonarensis form a clade to the exclusion of other Methylophaga species including type species of the genus, M. marina.[10] In 2013, INRS microbiologist Richard Villemur and colleagues added their newly described species M. nitratireducenticrescens and M. frappieri to this clade based on 16S rRNA analysis as well.[11] All of the species in this clade are alkaliphilic.[10][11]

• Type strain of Methylophaga muralis at BacDive - the Bacterial Diversity Metadatabase