title: Effects of light and low oxygen tension on pigment biosynthesis in Halobacterium salinarum, revealed by a novel method to quantify both retinal and carotenoids.
abstract: A novel method for analyzing halobacterial pigments was developed, in which retinal was liberated from halobacterial rhodopsins as retinal oxime by hydroxylamine, ethyl beta-apo-8'-carotenoate was introduced as an internal standard, and the pigments including bacterioruberin and beta-carotene were analyzed by HPLC at the same time. With this method, we revealed that light enhances the biosynthesis of bacterioruberin and the conversion of beta-carotene to retinal, but does not affect beta-carotene biosynthesis in Halobacterium salinarum strain Oyon Moussa-16. Low oxygen tension given in the light brought a slight increase in retinal accumulation, although its biosynthesis from beta-carotene is an oxygenation reaction. This paradox could be explained by the increase in beta-carotene biosynthesis.
authors.affiliation: Microbiology Department, Faculty of Science, Ain Shams University, Cairo, Egypt.
authors.forename: Wael S M
authors.initials: WS
authors.lastname: El-Sayed
authors.forename: Shinichi
authors.initials: S
authors.lastname: Takaichi
authors.forename: Haruo
authors.initials: H
authors.lastname: Saida
authors.forename: Masahiro
authors.initials: M
authors.lastname: Kamekura
authors.forename: Mohamed
authors.initials: M
authors.lastname: Abu-Shady
authors.forename: Humitake
authors.initials: H
authors.lastname: Seki
authors.forename: Tomohiko
authors.initials: T
authors.lastname: Kuwabara
mesh_terms: D002338:Carotenoids / Q000096:biosynthesis*; D003624:Darkness; D006217:Halobacterium / Q000187:drug effects* / Q000378:metabolism; D019811:Hydroxylamine / Q000494:pharmacology; D008027:Light; D010100:Oxygen / Q000494:pharmacology*; D010860:Pigments, Biological / Q000096:biosynthesis* / Q000302:isolation & purification; D012172:Retinaldehyde / Q000096:biosynthesis*; D019207:beta Carotene / Q000096:biosynthesis
chemical_list: D010860:Pigments, Biological; D019207:beta Carotene; D019811:Hydroxylamine; C002951:bacterioruberin; D002338:Carotenoids; D012172:Retinaldehyde; D010100:Oxygen