title: Carbon isotopic fractionations associated with thermophilic bacteria Thermotoga maritima and Persephonella marina.
abstract: Stable carbon isotopes can provide insight into carbon cycling pathways in natural environments. We examined carbon isotope fractionations associated with a hyperthermophilic fermentative bacterium, Thermotoga maritima, and a thermophilic chemolithoautotrophic bacterium Persephonella marina. In T. maritima, phospholipid fatty acids (PLFA) are slightly enriched in 13C relative to biomass (epsilon = 0.1-0.8 per thousand). However, PLFA and biomass are depleted in 13C relative to the substrate glucose by approximately 8 per thousand. In P. marina, PLFA are 1.8-14.5 per thousand enriched in 13C relative to biomass, which suggests that the reversed tricarboxylic acid (TCA) cycle or the 3-hydroxypropionate pathway may be used for CO2 fixation. This is supported by small fractionation between biomass and CO2 (epsilon = -3.8 per thousand to -5.0 per thousand), which is similar to fractionations reported for other organisms using similar CO2 fixation pathways. Identification of the exact pathway will require biochemical assay for specific enzymes associated with the reversed TCA cycle or the 3-hydroxypropionate pathway.
authors.affiliation: Department of Geological Sciences, University of Missouri, Columbia, MO 65211, USA. zhangcl@missouri.edu
authors.forename: Chuanlun L
authors.initials: CL
authors.lastname: Zhang
authors.forename: Qi
authors.initials: Q
authors.lastname: Ye
authors.forename: Anna-Louise
authors.initials: AL
authors.lastname: Reysenbach
authors.forename: Dorothee
authors.initials: D
authors.lastname: Götz
authors.forename: Aaron
authors.initials: A
authors.lastname: Peacock
authors.forename: David C
authors.initials: DC
authors.lastname: White
authors.forename: Juske
authors.initials: J
authors.lastname: Horita
authors.forename: David R
authors.initials: DR
authors.lastname: Cole
authors.forename: Jon
authors.initials: J
authors.lastname: Fong
authors.forename: Lisa
authors.initials: L
authors.lastname: Pratt
authors.forename: Jiasong
authors.initials: J
authors.lastname: Fang
authors.forename: Yongsong
authors.initials: Y
authors.lastname: Huang
mesh_terms: D002245:Carbon Dioxide / Q000032:analysis; D002247:Carbon Isotopes / Q000032:analysis*; D005227:Fatty Acids / Q000032:analysis; D013696:Temperature; D020124:Thermotoga maritima / Q000737:chemistry* / Q000254:growth & development / Q000378:metabolism; D013997:Time Factors
chemical_list: D002247:Carbon Isotopes; D005227:Fatty Acids; D002245:Carbon Dioxide