N atrialba

Abstract

Na.tri.al'ba. N.L. n. natron (arbitrarily derived from the Arabic n. natrun or natron ) soda, sodium carbonate; L. fem. adj. alba , white; N.L. fem. n. Natrialba , sodium white; referring to the high sodium ion requirement and the pigmentless colonies of the type species. Euryarchaeota / Halobacteria / Natrialbales / Natrialbaceae / Natrialba Strains of the genus Natrialba are extremely halophilic, with growth occurring in media containing 1.6–5.3 M NaCl. Temperatures between 20 and 60°C support growth. They are neutrophilic or alkaliphilic. Neutrophilic strains grow optimally at pH 7.0–8.0, while alkaliphilic strains grow up to pH 10.5–11.0 with optima at 9.0–9.5. Neutrophilic nonpigmented species are Natrialba asiatica , Natrialba aegyptiaca , and Natrialba taiwanensis , while alkaliphilic red‐pigmented species are Natrialba chahannaoensis , Natrialba hulunbeirensis , and Natrialba magadii . Cells lyse in distilled water. They are oxidase‐ and catalase‐positive, chemoorganotrophic, and aerobic. No growth is observed on single substrates. Most species reduce nitrate to nitrite. Neutrophilic species produce acids from sugars. Phylogenetically, the genus is closely related to the genera Haloterrigena , Natrinema , Natronorubrum , and Natronolimnobius . The major membrane polar lipids are C 20 C 20 and C 20 C 25 glycerol diether derivatives of PG and PGP‐Me. Neutrophilic species possess a glycolipid, S2‐DGD (disulfated diglycosyl diether), in addition, while alkaliphilic species do not. Isolates have been recovered from salterns, beach sands, salty soil, and soda lakes. DNA G + C content (mol%) : 60.3–64.3. The DNA may contain a major and a minor component. Type species : Natrialba asiatica Kamekura and Dyall‐Smith 1996, 625 VP (effective publication: Kamekura and Dyall‐Smith 1995, 348).