Cell suspensions of the haloarchaea Halorubrum sodomense and Halobacterium salinarum and the extremely halophilic bacterium Salinibacter ruber (Bacteroidetes) in saturated solutions of chlorides and sulfates (NaCl, KCl, MgSO4·7H2O, K2SO4, and (NH4)Al(SO4)2·12H2O) were left to evaporate to produce micrometric inclusions in laboratory-grown crystals. Raman spectra of these pinkish inclusions were obtained using a handheld Raman spectrometer with green excitation (532 nm). This portable instrument does not include any microscopic tool. Acceptable Raman spectra of carotenoids were obtained in the range of 200-4000 cm-1. This detection achievement was related to the mode of illumination and collection of scattered light as well as due to resonance Raman enhancement of carotenoid signals under green excitation. The position of diagnostic Raman carotenoid bands corresponds well to those specific carotenoids produced by a given halophile. To our best knowledge, this is the first study of carotenoids included in the laboratory in crystalline chlorides and sulfates, using a miniature portable Raman spectrometer. Graphical abstract ᅟ.
- Klíčová slova
- Carotenoids, Halophilic prokaryotes, Inclusions, Miniature Raman spectrometer, Salts,
- MeSH
- Bacteroidetes chemie MeSH
- chlorid draselný chemie MeSH
- chlorid sodný chemie MeSH
- Halobacterium salinarum chemie MeSH
- Halorubrum chemie MeSH
- karotenoidy analýza MeSH
- limita detekce MeSH
- Ramanova spektroskopie přístrojové vybavení MeSH
- sírany chemie MeSH
- Publikační typ
- časopisecké články MeSH
- Názvy látek
- chlorid draselný MeSH
- chlorid sodný MeSH
- karotenoidy MeSH
- sírany MeSH
Laboratory cultures of a number of red extremely halophilic Archaea (Halobacterium salinarum strains NRC-1 and R1, Halorubrum sodomense, Haloarcula valismortis) and of Salinibacter ruber, a red extremely halophilic member of the Bacteria, have been investigated by Raman spectroscopy using 514.5nm excitation to characterize their carotenoids. The 50-carbon carotenoid α-bacterioruberin was detected as the major carotenoid in all archaeal strains. Raman spectroscopy also detected bacterioruberin as the main pigment in a red pellet of cells collected from a saltern crystallizer pond. Salinibacter contains the C40-carotenoid acyl glycoside salinixanthin (all-E, 2'S)-2'-hydroxy-1'-[6-O-(methyltetradecanoyl)-β-d-glycopyranosyloxy]-3',4'-didehydro-1',2'-dihydro-β,ψ-carotene-4-one), for which the Raman bands assignments of are given here for the first time.
- MeSH
- Bacteroidetes chemie MeSH
- glykosidy chemie izolace a purifikace MeSH
- Haloarcula chemie MeSH
- Halobacteriaceae chemie MeSH
- Halobacterium salinarum chemie MeSH
- Halorubrum chemie MeSH
- karotenoidy chemie izolace a purifikace MeSH
- Ramanova spektroskopie MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- bacterioruberin MeSH Prohlížeč
- glykosidy MeSH
- karotenoidy MeSH
- salinixanthin MeSH Prohlížeč
