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Liao S, Sherman G, Huang Y. Elucidation of double-bond positions of polyunsaturated alkenes through gas chromatography/mass spectrometry analysis of mono-dimethyl disulfide derivatives. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2022; 36:e9228. [PMID: 34845773 DOI: 10.1002/rcm.9228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2021] [Revised: 10/24/2021] [Accepted: 11/22/2021] [Indexed: 06/13/2023]
Abstract
RATIONALE Derivatization with dimethyl disulfide (DMDS) followed by gas chromatography/mass spectrometry (GC/MS) analysis is a well-established method for locating double-bond position on the alkyl chain of mono-unsaturated compounds such as alkenes. For alkenes containing more than one double bond, however, the conventional DMDS derivatization approach forms poly- or cyclized DMDS adducts whose mass spectra are difficult to interpret in terms of double-bond positions. In this study, we report an efficient experimental procedure to produce mono-DMDS adducts for polyunsaturated alkenes with two to six double bonds. GC/MS analyses of these mono-DMDS adducts yield highly characteristic mass fragments, allowing unambiguous assignments of double-bond positions on the alkyl chain. We also apply our new approach (i.e., preferential formation of mono-DMDS adducts during derivatization with DMDS) to determine the double-bond positions of unsaturated alkenes produced by laboratory cultured Isochrysis litoralis, a haptophyte algal species. METHODS Alkenes from different sources were derivatized with DMDS at 25°C for 20 to 160 min. The mass spectra of mono-DMDS adducts were obtained by GC/EI-MS analysis of reaction products which contain chromatographically resolved mono-DMDS adducts. RESULTS Mass spectra of corresponding mono-DMDS adducts contain prominent diagnostic ions that allow a conclusive elucidation of double-bond positions. In culture samples of Isochrysis litoralis, a series of novel mono- to tri-unsaturated C31 alkenes (9-C31:1 , 6,9-C31:2 , 6,22-C31:2 , 6,25-C31:2 , 9,22-C31:2 , 6,9,25-C31:3 ) were discovered for the first time. CONCLUSIONS A highly efficient DMDS derivatization approach is developed to yield abundant mono-DMDS adducts of polyunsaturated alkyl alkenes for elucidating double-bond positions using GC/MS.
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Affiliation(s)
- Sian Liao
- Department of Chemistry, Brown University, Providence, RI, USA
- Institute at Brown for Environment and Society, Brown University, Providence, RI, USA
| | - Gordon Sherman
- Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, USA
| | - Yongsong Huang
- Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, USA
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Ikeda MA, Nakamura H, Sawada K. Long-chain alkenes and alkadienes of eight lichen species collected in Japan. PHYTOCHEMISTRY 2021; 189:112823. [PMID: 34098255 DOI: 10.1016/j.phytochem.2021.112823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2021] [Revised: 05/12/2021] [Accepted: 05/24/2021] [Indexed: 06/12/2023]
Abstract
The hydrocarbons of eight lichen species isolated in Japan were analyzed, and diverse mono-, di-, and tri-unsaturated alkenes were detected. The positions of the double bonds of C17 alkadienes (heptadecadiene) and C17-C20 alkenes were determined by mass spectrometry of their dimethyl disulfide adducts. We found that the six lichens containing green algal photobionts were distinguished by the presence of 1,8-heptadecadiene, 6,9-heptadecadiene, and 8- and 7-heptadecenes. On the other hand, 1-octadecene, 4-octadecene, and 5-nonadecene were the major alkene components of the two lichens with cyanobacterial photobionts. These alkadienes and alkenes were present in large quantities in the lichen samples. In particular, 1,8-heptadecadiene accounted for more than 90% of the total alkenes in all four lichens containing it. Our results provide new insights into the origin of C17 alkadienes and C17-C20 alkenes in environmental and geological samples, and these alkenes can potentially be applied as lichen biomarkers.
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Affiliation(s)
- Masashi A Ikeda
- Department of Natural History Sciences, Graduate School of Science, Hokkaido University, N10W8, Kita-ku, Sapporo, 060-0810, Japan.
| | - Hideto Nakamura
- Department of Geosciences, Graduate School of Science, Osaka City University, Sugimoto 3-3-138, Sumiyoshi-ku, Osaka, 558-8585, Japan
| | - Ken Sawada
- Department of Natural History Sciences, Graduate School of Science, Hokkaido University, N10W8, Kita-ku, Sapporo, 060-0810, Japan; Department of Earth and Planetary Sciences, Faculty of Science, Hokkaido University, N10W8, Kita-ku, Sapporo, 060-0810, Japan
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Environmental factors controlling the distributions of Botryococcus braunii (A, B and L) biomarkers in a subtropical freshwater wetland. Sci Rep 2018; 8:8626. [PMID: 29872136 PMCID: PMC5988687 DOI: 10.1038/s41598-018-26900-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2018] [Accepted: 05/17/2018] [Indexed: 11/08/2022] Open
Abstract
Here we report the molecular biomarker co-occurrence of three different races of Botryococcus braunii (B. braunii) in the freshwater wetland ecosystem of the Florida Everglades, USA. Thespecific biomarkers include C32-C34 botryococcenes for race B, C27-C32 n-alkadienes and n-alkatrienes for race A, and lycopadiene for race L. The n-alkadienes and n-alkatrienes were present up to 3.1 and 69.5 µg/g dry weight (dw), while lycopadiene was detected in lower amounts up to 3.0 and 1.5 µg/g dw in periphyton and floc samples, respectively. Nutrient concentrations (P and N) did not significantly correlate with the abundances of these compounds. In contrast, n-alkadienes and n-alkatrienes were present in wider diversity and higher abundance in the floc from slough (deeper water and longer hydroperiod) than ridge (shallower water and shorter hydroperiod) locations. n-Alkadienes, n-alkatrienes, and lycopadiene, showed lower δ13C values from -40.0 to -35.5‰, suggesting that the source organisms B. braunii at least partially utilize recycled CO2 (13C depleted) produced from OM respiration rather than atmospheric CO2 (13C enriched) as the major carbon sources.
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Santalova EA, Denisenko VA. Analysis of the Configuration of an Isolated Double Bond in Some Lipids by Selective Homonuclear Decoupling. Nat Prod Commun 2017. [DOI: 10.1177/1934578x1701201225] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The purpose of this report is to demonstrate that selective homonuclear decoupling can be used as an alternative for 13C NMR method for identifying configuration of an isolated (mid-chain) double bond in some lipids. Using homodecoupling of allylic protons, the coupling constants Jcis or Jtrans between the olefinic protons of some fatty acid methyl esters and related compounds with ( n–7) and ( n–9) terminal structures were evaluated. The optimal conditions of the homodecoupling experiments on these compounds were examined. Empirical rules were proposed to predict the results of homodecoupling experiments on lipid with an isolated double bond.
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Affiliation(s)
- Elena A. Santalova
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far-Eastern Branch of Russian Academy of Sciences, Pr. 100 let Vladivostoku, 159, Vladivostok 690022, Russia
| | - Vladimir A. Denisenko
- G.B. Elyakov Pacific Institute of Bioorganic Chemistry, Far-Eastern Branch of Russian Academy of Sciences, Pr. 100 let Vladivostoku, 159, Vladivostok 690022, Russia
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Deng P, Zhong D, Wang X, Dai Y, Zhou L, Leng Y, Chen X. Analysis of diacylglycerols by ultra performance liquid chromatography-quadrupole time-of-flight mass spectrometry: Double bond location and isomers separation. Anal Chim Acta 2016; 925:23-33. [PMID: 27188314 DOI: 10.1016/j.aca.2016.04.051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Revised: 04/18/2016] [Accepted: 04/22/2016] [Indexed: 02/02/2023]
Abstract
Diacylglycerols (DAGs) are important lipid intermediates and have been implicated in human diseases. Isomerism complicates their mass spectrometric analysis; in particular, it is difficult to identify fatty acid substituents and locate the double bond positions in unsaturated DAGs. We have developed an analytical strategy using ultra-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) in conjunction with dimethyl disulfide (DMDS) derivatization and collision cross-section (CCS) measurement to characterize DAGs in biological samples. The method employs non-aqueous reversed-phase chromatographic separation and profile collision energy (CE) mode for MS(E) and MS/MS analyses. Three types of fragment ions were produced simultaneously. Hydrocarbon ions (m/z 50-200) obtained at high CE helped to distinguish unsaturated and saturated DAGs rapidly. Neutral loss ions and acylium ions (m/z 300-400) produced at low CE were used to identify fatty acid substituents. Informative methyl thioalkane fragment ions were used to locate the double bonds of unsaturated DAGs. Mono-methylthio derivatives were formed mainly by the reaction of DAGs with DMDS, where methyl thiol underwent addition to the first double bond farthest from the ester terminus of unsaturated fatty acid chains. The addition of CCS values maximized the separation of isomeric DAG species and improved the confidence of DAG identification. Fourteen DAGs were identified in mouse myotube cells based on accurate masses, characteristic fragment ions, DMDS derivatization, and CCS values.
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Affiliation(s)
- Pan Deng
- Centre for Drug Metabolism and Pharmacokinetics Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201210, China
| | - Dafang Zhong
- Centre for Drug Metabolism and Pharmacokinetics Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201210, China; State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Xi Wang
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Yulu Dai
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Lei Zhou
- Centre for Drug Metabolism and Pharmacokinetics Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201210, China
| | - Ying Leng
- State Key Laboratory of Drug Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 555 Zu Chong Zhi Road, Shanghai 201203, China
| | - Xiaoyan Chen
- Centre for Drug Metabolism and Pharmacokinetics Research, Shanghai Institute of Materia Medica, Chinese Academy of Sciences, 501 Haike Road, Shanghai 201210, China.
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Nakamura H, Sawada K, Araie H, Suzuki I, Shiraiwa Y. n-Nonacosadienes from the marine haptophytes Emiliania huxleyi and Gephyrocapsa oceanica. PHYTOCHEMISTRY 2015; 111:107-113. [PMID: 25595675 DOI: 10.1016/j.phytochem.2014.12.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Revised: 11/30/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
The hydrocarbons in cultures of marine haptophytes Emiliania huxleyi NIES837 and Gephyrocapsa oceanica NIES1315 were analyzed, and nonacosadienes and hentriacontadienes were detected as the major compounds in both strains. C29 and C31 monoenes and di-, tri- and tetra-unsaturated C33 alkenes were also detected as minor compounds but not C37 and C38 alkenes. The positions of the double bonds in the C29 and C31 alkenes were determined by mass spectrometry of their dimethyl disulfide (DMDS) adducts. Among the four C29 alkenes identified, the most abundant isomer was 2,20-nonacosadiene, and the other three compounds were 1,20-nonacosadiene, 3,20-nonacosadiene and 9-nonacosene, respectively. Hitherto, 2,20-nonacosadiene and 3,20-nonacosadiene were unknown to be natural products. The double bond at the n-9 (ω9) position in these C29 alkenes is hypothesized to be derived from precursors of unsaturated fatty acids possessing an n-9 double bond, such as (9Z)-9-octadecenoic acid. Nonacosadienes have the potential for being used as distinct haptophyte biomarkers.
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Affiliation(s)
- Hideto Nakamura
- Department of Natural History Sciences, Faculty of Science, Hokkaido University, N10W8, Kita-ku, Sapporo 060-0810, Japan; CREST, Japan Science and Technology Agency (JST), N10W8, Kita-ku, Sapporo 060-0810, Japan.
| | - Ken Sawada
- Department of Natural History Sciences, Faculty of Science, Hokkaido University, N10W8, Kita-ku, Sapporo 060-0810, Japan; CREST, Japan Science and Technology Agency (JST), N10W8, Kita-ku, Sapporo 060-0810, Japan
| | - Hiroya Araie
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; CREST, Japan Science and Technology Agency (JST), 1-1-1 Tennodai, Tsukuba 305-8572, Japan
| | - Iwane Suzuki
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; CREST, Japan Science and Technology Agency (JST), 1-1-1 Tennodai, Tsukuba 305-8572, Japan
| | - Yoshihiro Shiraiwa
- Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba 305-8572, Japan; CREST, Japan Science and Technology Agency (JST), 1-1-1 Tennodai, Tsukuba 305-8572, Japan
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Dahmen JL, Leblond JD. Structural Analysis and Cellular Localization of Polyunsaturated C27 Hydrocarbons in the Marine Dinoflagellate, Pyrocystis lunula (Dinophyceae). Protist 2013; 164:183-94. [DOI: 10.1016/j.protis.2012.06.002] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2012] [Revised: 06/26/2012] [Accepted: 06/27/2012] [Indexed: 10/28/2022]
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Frias JA, Goblirsch BR, Wackett LP, Wilmot CM. Cloning, purification, crystallization and preliminary X-ray diffraction of the OleC protein from Stenotrophomonas maltophilia involved in head-to-head hydrocarbon biosynthesis. Acta Crystallogr Sect F Struct Biol Cryst Commun 2010; 66:1108-10. [PMID: 20823539 PMCID: PMC2935240 DOI: 10.1107/s1744309110031751] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Accepted: 08/07/2010] [Indexed: 11/10/2022]
Abstract
OleC, a biosynthetic enzyme involved in microbial hydrocarbon biosynthesis, has been crystallized. Synchrotron X-ray diffraction data have been collected to 3.4 A resolution. The crystals belonged to space group P3(1)21 or P3(2)21, with unit-cell parameters a=b=98.8, c=141.0 A.
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9
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Structure, function, and insights into the biosynthesis of a head-to-head hydrocarbon in Shewanella oneidensis strain MR-1. Appl Environ Microbiol 2010; 76:3842-9. [PMID: 20418444 DOI: 10.1128/aem.00433-10] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A polyolefinic hydrocarbon was found in nonpolar extracts of Shewanella oneidensis MR-1 and identified as 3,6,9,12,15,19,22,25,28-hentriacontanonaene (compound I) by mass spectrometry, chemical modification, and nuclear magnetic resonance spectroscopy. Compound I was shown to be the product of a head-to-head fatty acid condensation biosynthetic pathway dependent on genes denoted as ole (for olefin biosynthesis). Four ole genes were present in S. oneidensis MR-1. Deletion of the entire oleABCD gene cluster led to the complete absence of nonpolar extractable products. Deletion of the oleC gene alone generated a strain that lacked compound I but produced a structurally analogous ketone. Complementation of the oleC gene eliminated formation of the ketone and restored the biosynthesis of compound I. A recombinant S. oneidensis strain containing oleA from Stenotrophomonas maltophilia strain R551-3 produced at least 17 related long-chain compounds in addition to compound I, 13 of which were identified as ketones. A potential role for OleA in head-to-head condensation was proposed. It was further proposed that long-chain polyunsaturated compounds aid in adapting cells to a rapid drop in temperature, based on three observations. In S. oneidensis wild-type cells, the cellular concentration of polyunsaturated compounds increased significantly with decreasing growth temperature. Second, the oleABCD deletion strain showed a significantly longer lag phase than the wild-type strain when shifted to a lower temperature. Lastly, compound I has been identified in a significant number of bacteria isolated from cold environments.
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Mackinder LCM, Worthy CA, Biggi G, Hall M, Ryan KP, Varsani A, Harper GM, Wilson WH, Brownlee C, Schroeder DC. A unicellular algal virus, Emiliania huxleyi virus 86, exploits an animal-like infection strategy. J Gen Virol 2009; 90:2306-16. [DOI: 10.1099/vir.0.011635-0] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Lin YH, Chang FL, Tsao CY, Leu JY. Influence of growth phase and nutrient source on fatty acid composition of Isochrysis galbana CCMP 1324 in a batch photoreactor. Biochem Eng J 2007. [DOI: 10.1016/j.bej.2007.04.014] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Rontani JF, Prahl FG, Volkman JK. Characterization of unusual alkenones and alkyl alkenoates by electron ionization gas chromatography/mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:583-8. [PMID: 16429480 DOI: 10.1002/rcm.2346] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Unusual long-chain, diunsaturated alkenones and alkyl alkenoates exhibiting double bonds separated by three methylene units instead of the more usual five were characterized by electron ionization (EI) gas chromatography/mass spectrometry. In a first step, the positions of the double bonds of these compounds (isolated from Holocene Black Sea sediments) were confirmed after OsO4 treatment and silylation. Mass spectra of the resulting tetratrimethylsilyloxy derivatives allowed unambiguous determination of the positions of unsaturations. The EI mass spectra of the non-derivatized compounds were then compared with those of the alkenones and alkyl alkenoates having double bonds separated by five methylene units. Specific fragment ions resulting from gamma-H rearrangements were found to be prominent in EI mass spectra of these unusual 'Black Sea' diunsaturated alkenones and alkyl alkenoates. These fragment ions can be used to characterize these compounds in natural samples without the need for laborious derivatization treatments.
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Affiliation(s)
- J-F Rontani
- Laboratoire de Microbiologie de Géochimie et d'Ecologie Marines (LMGEM-UMR 6117), Centre d'Océanologie de Marseille, F-13288 Marseille, France.
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Rontani JF, Beker B, Volkman JK. Long-chain alkenones and related compounds in the benthic haptophyte Chrysotila lamellosa Anand HAP 17. PHYTOCHEMISTRY 2004; 65:117-126. [PMID: 14697277 DOI: 10.1016/j.phytochem.2003.09.021] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The neutral lipid compositions of the coastal haptophyte Chrysotila lamellosa HAP 17 grown in batch culture at 10 and 20 degrees C have been determined. A comparison was also made between the lipid compositions of cells harvested in early and late stationary phase. This species contains a suite of very long-chain C(37)-C(40) alkenones and alkenoates as found in a few microalgae from the Haptophyta. The distributions of these compounds show some differences to earlier reports of different strains of this alga, which are only in part attributable to culture conditions. A suite of long-chain alkenols, the reduced form of the alkenones, was characterized for the first time. The abundance of these compounds was only 1.5% of that of the corresponding alkenones, and the relative proportion of C(37)-C(38) constituents depended on growth temperature. These data show that haptophyte algae are a possible source of the alkenols found in some marine sediments, but the small amounts found suggest that other sources such as bacterial reduction of alkenones are more likely in highly reducing sediments. A mixture of C(29)-C(33) n-alkenes, dominated by the C(31:1) monoene, was found in marked contrast to previous analyses of other strains which reported only the presence of a C(31:2) diene. The sterol distribution included the common haptophyte sterol 24alpha-methylcholesta-5,22E-dien-3beta-ol (epi-brassicasterol) as well as significant amounts of Delta(5)- and Delta(5,22)-C(29) sterols.
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Affiliation(s)
- Jean-François Rontani
- Laboratoire d'Océanographie et de Biogéochimie (UMR CNRS 6535), Centre d'Océanologie de Marseille (OSU), Campus de Luminy, case 901, F-13288, Marseille, France.
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Mouzdahir A, Grossi V, Bakkas S, Rontani JF. Visible light-dependent degradation of long-chain alkenes in killed cells of Emiliania huxleyi and Nannochloropsis salina. PHYTOCHEMISTRY 2001; 56:677-684. [PMID: 11314952 DOI: 10.1016/s0031-9422(00)00468-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Photosensitized degradation rates of phytoplanktonic n-alkenes under visible light exposure were determined in laboratory experiments. Killed cells of Emiliania huxleyi and Nannochloropsis salina were used as source of biogenic alkenes. In E. huxleyi killed cells, minor C31 and C33 n-alkenes were strongly photodegraded, while the major C37 and C38 n-alkenes appeared particularly recalcitrant towards photochemical processes. This particular photochemical recalcitrance has been attributed to the chemical structure and localization of these hydrocarbons in the cells. Most of the n-alkenes of N. salina were strongly photodegraded in killed cells. The photodegradation of phytoplanktonic alkenes showed apparent second-order kinetics with respect to light exposure, and the half-life doses obtained logically decrease with increasing number of double bonds in these compounds. These results strongly suggest that significant amounts of phytoplanktonic n-alkenes must be photodegraded in the euphotic zone of the oceans during senescence.
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Affiliation(s)
- A Mouzdahir
- Laboratoire d'Océanographie et de Biogeochinie (UMR CNRS 6535), Centre d'Océanologie de Marseille (OSU), France
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Damsté JS, Schouten S, Rijpstra WI, Hopmans EC, Peletier H, Gieskes WW, Geenevasen JA. Novel polyunsaturated n-alkenes in the marine diatom Rhizosolenia setigera. EUROPEAN JOURNAL OF BIOCHEMISTRY 2000; 267:5727-32. [PMID: 10971583 DOI: 10.1046/j.1432-1327.2000.01636.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Four previously unknown n-C25 and n-C27 heptaenes of the marine diatom Rhizosolenia setigera were isolated and identified using NMR spectroscopy. They possess six methylene interrupted (Z)-double bonds starting at C-3 and an additional terminal or n-2 (Z)-double bond. Structural and stable carbon isotopic evidence suggests that these polyenes are biosynthesized by chain elongation of the C22:6n-3 fatty acid, followed by decarboxylation and introduction of double bonds at specific positions.
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Affiliation(s)
- J S Damsté
- Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, Department of Marine Biology, University of Groningen, the Netherlands.
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Grossi V, Raphel D, Aubert C, Rontani JF. The effect of growth temperature on the long-chain alkenes composition in the marine coccolithophorid Emiliania huxleyi. PHYTOCHEMISTRY 2000; 54:393-399. [PMID: 10897480 DOI: 10.1016/s0031-9422(00)00120-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The hydrocarbon fraction of a pure culture of Emiliania huxleyi, composed of a mixture of C31, C33, C37 and C38 polyunsaturated n-alkenes, appeared strongly dependent on the growth temperature of the alga between 8 degrees C and 25 degrees C. The total hydrocarbon content increased linearly with decreasing temperatures. C37 and C38 alkenes (which accounted for more than 90% of the total hydrocarbons) showed distinct changes in distribution compared to C31 and C33 alkenes, suggesting different biological syntheses and/or functions for these two groups of compounds. C37 and C38 alkenes and C37 methyl ketones (alkenones) all showed a trend to lower proportions of the two diunsaturated isomers and to higher proportions of the corresponding trienes with decreasing temperature. Unlike the alkenone unsaturation ratio (U37k'), ratios based on the C37 and C38 alkadi- and trienes could be linearly related to the growth temperature of E. huxleyi only between 15 degrees C and 25 degrees C. The modifications in the distribution of alkenes induced by varying temperature appeared, however, to be twice as fast as the modifications undergone by the alkenones. Although structurally and biochemically related, the distinct evolutions of alkenes and alkenones in response to changes in growth temperature might indicate that these two classes of compounds play two distinct physiological functions. The non-systematic linearity of relationships to temperature of parameters based on alkenes distribution suggested that these compounds are of limited use as paleotemperature indicator in the marine environment in contrast with the alkenones.
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Affiliation(s)
- V Grossi
- Laboratoire d'Océanographie et de Biogéochimie (UMR CNRS 6535), Centre d'Océanologie de Marseille (OSU), France.
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van der Meer MT, Schouten S, Ward DM, Geenevasen JA, Sinninghe Damste JS. All-cis hentriaconta-9,15,22-triene in microbial mats formed by the phototrophic prokaryote Chloroflexus. ORGANIC GEOCHEMISTRY 1999; 30:1585-1587. [PMID: 11543197 DOI: 10.1016/s0146-6380(99)00141-2] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
All-cis hentriaconta-9,15,22-triene (I) has been isolated from Chloroflexus mats, Yellowstone National Park (USA), and identified by GC-(HR)MS analysis of I and its hydrogenated and DMDS-derivatized products and by 1H and 13C NMR spectroscopy.
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Affiliation(s)
- M T van der Meer
- Netherlands Institute for Sea Research (NIOZ), Department of Marine Biogeochemistry and Toxicology, Den Burg.
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