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Pierre Metzger - One of the best experts on this subject based on the ideXlab platform.
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Lycopanerols I-L, four new Tetraterpenoid ethers from Botryococcus braunii.
Journal of Natural Products, 2003Co-Authors: Pierre Metzger, Marie Noelle Rager, Nicole Sellier, Claude LargeauAbstract:Four new Tetraterpenoid ethers, lycopanerols I-L (5-8), were isolated from a culture of a strain of the green microalga Botryococcus braunii (L race). The structures were determined by means of spectral analyses and chemical degradation. The relative stereochemistry of these ethers was established by ROESY NMR. A biogenetic relationship is proposed between lycopanerols and lycopadiene (1), the acyclic diunsaturated tetraterpene hydrocarbon synthesized by the alga.
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lycopanerols h two high molecular weight ether lipids from botryococcus braunii comprising an α tocopherol unit
Tetrahedron Letters, 2002Co-Authors: Pierre Metzger, Marie Noelle RagerAbstract:Two high molecular weight ether lipids, C151 and C153 lycopanerols H, have been isolated from the lipid extract of a strain of the green microalga Botryococcus braunii. These new compounds arise from the linkage via ether bridges of Tetraterpenoid, n-alkylphenol and α-tocopherol units. Their structures have been elucidated by Mass and NMR spectral analysis.
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six novel Tetraterpenoid ethers lycopanerols b g and some other constituents from the green microalga botryococcus braunii
Phytochemistry, 2000Co-Authors: Marie Noelle Rager, Pierre MetzgerAbstract:Abstract Six novel Tetraterpenoid ethers, lycopanerols B-G, were isolated from lipidic extracts of the green microalga Botryococcus braunii (L race), along with a series of phytyl esters and α- and β-tocopherols. The structures of the compounds were determined by means of spectral analyses including 2D NMR techniques. A biogenetic relationship is proposed between lycopanerols and lycopadiene, the acyclic diunsaturated Tetraterpenoid hydrocarbon synthesized by the alga.
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Lipids of Thermococcus hydrothermalis, an archaea isolated from a deep-sea hydrothermal vent
Lipids, 1998Co-Authors: Agnès Lattuati, Pierre Metzger, Jean Guezennec, Claude LargeauAbstract:The membrane lipids of a deep-sea hydrothermal vent archaea, Thermococcus hydrothermalis , were isolated, purified, and structurally characterized. On the basis of acid methanolysis and spectroscopic studies, the polar lipids, amounting to 4.5% (w/w) of the dry cells, comprised diphytanyl glycerol diethers and dibiphytanyldiglycerol tetraethers, in a 45∶55 ratio. No cyclopentane ring was present in the tetraethers. From the neutral lipids, accounting for 0.4% (w/w) of the dry cells, besides low amounts of di- and tetraethers occurring in a free form, four acyclic Tetraterpenoid hydrocarbons, di- and triunsaturated were identified. All were structurally related to lycopane. The presence of these hydrocarbons provides some evidence that lycopane, widely distributed in oceans, could be derived, at least partially, from the hydrocarbons synthesized by some thermophilic Archaea. Finally, analysis of the uninoculated culture medium indicates that fatty acid derivatives and some steroid and triterpenoid compounds identified in the lipidic extract of the archaea originated from the culture medium.
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Lipids of Thermococcus hydrothermalis, an archaea isolated from a deep‐sea hydrothermal vent
Lipids, 1998Co-Authors: Agnès Lattuati, Pierre Metzger, Jean Guezennec, Claude LargeauAbstract:The membrane lipids of a deep-sea hydrothermal vent archaea, Thermococcus hydrothermalis, were isolated, purified, and structurally characterized. On the basis of acid methanolysis and spectroscopic studies, the polar lipids, amounting to 4.5% (w/w) of the dry cells, comprised diphytanyl glycerol diethers and dibiphytanyldiglycerol tetraethers, in a 45∶55 ratio. No cyclopentane ring was present in the tetraethers. From the neutral lipids, accounting for 0.4% (w/w) of the dry cells, besides low amounts of di- and tetraethers occurring in a free form, four acyclic Tetraterpenoid hydrocarbons, di- and triunsaturated were identified. All were structurally related to lycopane. The presence of these hydrocarbons provides some evidence that lycopane, widely distributed in oceans, could be derived, at least partially, from the hydrocarbons synthesized by some thermophilic Archaea. Finally, analysis of the uninoculated culture medium indicates that fatty acid derivatives and some steroid and triterpenoid compounds identified in the lipidic extract of the archaea originated from the culture medium.
Timothy P. Devarenne - One of the best experts on this subject based on the ideXlab platform.
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Tetraterpene Synthase Substrate and Product Specificity in the Green Microalga Botryococcus braunii Race L
ACS chemical biology, 2017Co-Authors: Hem R Thapa, Su Tang, James C. Sacchettini, Timothy P. DevarenneAbstract:Recently, the biosynthetic pathway for lycopadiene, a C40 Tetraterpenoid hydrocarbon, was deciphered from the L race of Botryococcus braunii, an alga that produces hydrocarbon oils capable of being converted into combustible fuels. The lycopadiene pathway is initiated by the squalene synthase (SS)-like enzyme lycopaoctaene synthase (LOS), which catalyzes the head-to-head condensation of two C20 geranylgeranyl diphosphate (GGPP) molecules to produce C40 lycopaoctaene. LOS shows unusual substrate promiscuity for SS or SS-like enzymes by utilizing C15 farnesyl diphosphate (FPP) and C20 phytyl diphosphate in addition to GGPP as substrates. These three substrates can be combined by LOS individually or in combinations to produce six different hydrocarbons of C30, C35, and C40 chain lengths. To understand LOS substrate and product specificity, rational mutagenesis experiments were conducted based on sequence alignment with several SS proteins as well as a structural comparison with the human SS (HSS) crystal str...
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Tetraterpene Synthase Substrate and Product Specificity in the Green Microalga Botryococcus braunii Race L
2017Co-Authors: Hem R Thapa, Su Tang, James C. Sacchettini, Timothy P. DevarenneAbstract:Recently, the biosynthetic pathway for lycopadiene, a C40 Tetraterpenoid hydrocarbon, was deciphered from the L race of Botryococcus braunii, an alga that produces hydrocarbon oils capable of being converted into combustible fuels. The lycopadiene pathway is initiated by the squalene synthase (SS)-like enzyme lycopaoctaene synthase (LOS), which catalyzes the head-to-head condensation of two C20 geranylgeranyl diphosphate (GGPP) molecules to produce C40 lycopaoctaene. LOS shows unusual substrate promiscuity for SS or SS-like enzymes by utilizing C15 farnesyl diphosphate (FPP) and C20 phytyl diphosphate in addition to GGPP as substrates. These three substrates can be combined by LOS individually or in combinations to produce six different hydrocarbons of C30, C35, and C40 chain lengths. To understand LOS substrate and product specificity, rational mutagenesis experiments were conducted based on sequence alignment with several SS proteins as well as a structural comparison with the human SS (HSS) crystal structure. Characterization of the LOS mutants in vitro identified Ser276 and Ala288 in the LOS active site as key amino acids responsible for controlling substrate binding, and thus the promiscuity of this enzyme. Mutating these residues to those found in HSS largely converted LOS from lycopaoctaene production to C30 squalene production. Furthermore, these studies were confirmed in vivo by expressing LOS in E. coli cells metabolically engineered to produce high FPP and GGPP levels. These studies also offer insights into tetraterpene hydrocarbon metabolism in B. braunii and provide a foundation for engineering LOS for robust production of specific hydrocarbons of a desired chain length
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a squalene synthase like enzyme initiates production of Tetraterpenoid hydrocarbons in botryococcus braunii race l
Nature Communications, 2016Co-Authors: Hem R Thapa, Istvan Molnar, Mandar T Naik, Shigeru Okada, Kentaro Takada, Timothy P. DevarenneAbstract:The green microalga Botryococcus braunii is considered a promising biofuel feedstock producer due to its prodigious accumulation of hydrocarbon oils that can be converted into fuels. B. braunii Race L produces the C40 Tetraterpenoid hydrocarbon lycopadiene via an uncharacterized biosynthetic pathway. Structural similarities suggest this pathway follows a biosynthetic mechanism analogous to that of C30 squalene. Confirming this hypothesis, the current study identifies C20 geranylgeranyl diphosphate (GGPP) as a precursor for lycopaoctaene biosynthesis, the first committed intermediate in the production of lycopadiene. Two squalene synthase (SS)-like complementary DNAs are identified in race L with one encoding a true SS and the other encoding an enzyme with lycopaoctaene synthase (LOS) activity. Interestingly, LOS uses alternative C15 and C20 prenyl diphosphate substrates to produce combinatorial hybrid hydrocarbons, but almost exclusively uses GGPP in vivo. This discovery highlights how SS enzyme diversification results in the production of specialized Tetraterpenoid oils in race L of B. braunii.
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Bio-crude transcriptomics: Gene discovery and metabolic network reconstruction for the biosynthesis of the terpenome of the hydrocarbon oil-producing green alga, Botryococcus braunii race B (Showa)
BMC Genomics, 2012Co-Authors: Istvan Molnar, Jennifer H Wisecaver, Taylor L. Weiss, Timothy P. Devarenne, David Lopez, Matteo Pellegrini, Jeremiah D. HackettAbstract:BACKGROUND: Microalgae hold promise for yielding a biofuel feedstock that is sustainable, carbon-neutral, distributed, and only minimally disruptive for the production of food and feed by traditional agriculture. Amongst oleaginous eukaryotic algae, the B race of Botryococcus braunii is unique in that it produces large amounts of liquid hydrocarbons of terpenoid origin. These are comparable to fossil crude oil, and are sequestered outside the cells in a communal extracellular polymeric matrix material. Biosynthetic engineering of terpenoid bio-crude production requires identification of genes and reconstruction of metabolic pathways responsible for production of both hydrocarbons and other metabolites of the alga that compete for photosynthetic carbon and energy. RESULTS: A de novo assembly of 1,334,609 next-generation pyrosequencing reads form the Showa strain of the B race of B. braunii yielded a transcriptomic database of 46,422 contigs with an average length of 756 bp. Contigs were annotated with pathway, ontology, and protein domain identifiers. Manual curation allowed the reconstruction of pathways that produce terpenoid liquid hydrocarbons from primary metabolites, and pathways that divert photosynthetic carbon into Tetraterpenoid carotenoids, diterpenoids, and the prenyl chains of meroterpenoid quinones and chlorophyll. Inventories of machine-assembled contigs are also presented for reconstructed pathways for the biosynthesis of competing storage compounds including triacylglycerol and starch. Regeneration of S-adenosylmethionine, and the extracellular localization of the hydrocarbon oils by active transport and possibly autophagy are also investigated. CONCLUSIONS: The construction of an annotated transcriptomic database, publicly available in a web-based data depository and annotation tool, provides a foundation for metabolic pathway and network reconstruction, and facilitates further omics studies in the absence of a genome sequence for the Showa strain of B. braunii, race B. Further, the transcriptome database empowers future biosynthetic engineering approaches for strain improvement and the transfer of desirable traits to heterologous hosts.
André Pichette - One of the best experts on this subject based on the ideXlab platform.
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DFT Calculations and ROESY NMR Data for the Diastereochemical Characterization of Cytotoxic Tetraterpenoids from the Oleoresin of Abies balsamea.
Journal of natural products, 2015Co-Authors: Serge Lavoie, Charles Gauthier, Vakhtang Mshvildadze, Jean Legault, Benoit Roger, André PichetteAbstract:Eight non-carotenoid Tetraterpenoids, abibalsamins C-J (3-10), were isolated from the oleoresin of Abies balsamea. Their chemical structures were determined based on analysis of 1D/2D NMR and MS data. The assignment of their relative configurations was accomplished using homonuclear coupling constants in tandem with ROESY data. However, the presence of two stereogenic centers on a flexible side chain complicated the characterization. In silico models and ROESY data were analyzed in order to assign relative configurations of the isolated Tetraterpenoids. Abibalsamins B and H-J showed moderate cytotoxicity against human A549 lung carcinoma cells, with IC50 values ranging between 6.7 and 10 μM.
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DFT Calculations and ROESY NMR Data for the Diastereochemical Characterization of Cytotoxic Tetraterpenoids from the Oleoresin of Abies balsamea
Journal of Natural Products, 2015Co-Authors: Serge Lavoie, Charles Gauthier, Vakhtang Mshvildadze, Jean Legault, Benoit Roger, André PichetteAbstract:Copyright of Journal of Natural Products is the property of American Chemical Society and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
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Abibalsamins A and B, two new Tetraterpenoids from Abies balsamea oleoresin.
Organic letters, 2012Co-Authors: Serge Lavoie, Charles Gauthier, Vakhtang Mshvildadze, Jean Legault, S. Mercier, André PichetteAbstract:Abibalsamins A (1) and B (2), two unprecedented Tetraterpenoids featuring a 3,4-seco-rearranged lanostane system fused with a β-myrcene lateral chain via a [4 + 2] Diels–Alder cycloaddition, were isolated from the oleoresin of Abies balsamea. Their structures were elucidated by means of extensive 2D NMR, IR, and MS spectroscopy analyses. The absolute configuration of 1 was determined by single-crystal X-ray diffraction. Both compounds exhibited significant cytotoxic activity against cancer cell lines.
Marie Noelle Rager - One of the best experts on this subject based on the ideXlab platform.
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Lycopanerols I-L, four new Tetraterpenoid ethers from Botryococcus braunii.
Journal of Natural Products, 2003Co-Authors: Pierre Metzger, Marie Noelle Rager, Nicole Sellier, Claude LargeauAbstract:Four new Tetraterpenoid ethers, lycopanerols I-L (5-8), were isolated from a culture of a strain of the green microalga Botryococcus braunii (L race). The structures were determined by means of spectral analyses and chemical degradation. The relative stereochemistry of these ethers was established by ROESY NMR. A biogenetic relationship is proposed between lycopanerols and lycopadiene (1), the acyclic diunsaturated tetraterpene hydrocarbon synthesized by the alga.
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lycopanerols h two high molecular weight ether lipids from botryococcus braunii comprising an α tocopherol unit
Tetrahedron Letters, 2002Co-Authors: Pierre Metzger, Marie Noelle RagerAbstract:Two high molecular weight ether lipids, C151 and C153 lycopanerols H, have been isolated from the lipid extract of a strain of the green microalga Botryococcus braunii. These new compounds arise from the linkage via ether bridges of Tetraterpenoid, n-alkylphenol and α-tocopherol units. Their structures have been elucidated by Mass and NMR spectral analysis.
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six novel Tetraterpenoid ethers lycopanerols b g and some other constituents from the green microalga botryococcus braunii
Phytochemistry, 2000Co-Authors: Marie Noelle Rager, Pierre MetzgerAbstract:Abstract Six novel Tetraterpenoid ethers, lycopanerols B-G, were isolated from lipidic extracts of the green microalga Botryococcus braunii (L race), along with a series of phytyl esters and α- and β-tocopherols. The structures of the compounds were determined by means of spectral analyses including 2D NMR techniques. A biogenetic relationship is proposed between lycopanerols and lycopadiene, the acyclic diunsaturated Tetraterpenoid hydrocarbon synthesized by the alga.
Long-mei Zeng - One of the best experts on this subject based on the ideXlab platform.
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New precursor of Tetraterpenoids from the soft coral Sarcophyton glaucum.
Natural product research, 2012Co-Authors: Cui-xian Zhang, Jun Zhang, Qiong Guo, Ling-fang Lei, Long-mei ZengAbstract:One new precursor of Tetraterpenoids, Sarglaucol (1), along with eight known compounds have been isolated from the soft coral Sarcophyton glaucum collected from the Sanya Bay, Hainan Island, China. Their structures were elucidated through spectroscopic techniques including 1D- and 2D-NMR, and their relative configurations were also assigned by NMR and NOESY analysis. Compounds 1 showed weak antitumour activities.
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New Tetraterpenoid from the soft coral Sarcophyton tortuosum.
Journal of Asian Natural Products Research, 2007Co-Authors: W.-j. Lan, Su-jun Yan, Long-mei ZengAbstract:A novel Tetraterpenoid named methyl tortuoate C (1) has been isolated from the soft coral Sarcophyton tortuosum Tix.-Dur. The structure of 1 was determined on the basis of spectroscopic methods.
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Two new cytotoxic tetracyclic Tetraterpenoids from the soft coral Sarcophyton tortuosum.
Journal of natural products, 2004Co-Authors: Long-mei Zeng, W.-j. Lan, Guang-wen Zhang, Xiao-long Feng, Yong-ju Liang, Xiao-ping YangAbstract:Two new cytotoxic tetracyclic Tetraterpenoids, methyl tortuoate A (1) and methyl tortuoate B (2), along with the known methyl sartortuoate (3) were isolated from the soft coral Sarcophyton tortuosum. The structures of 1 and 2 were established by spectroscopic methods, mainly on the basis of 2D NMR techniques, and were confirmed by single-crystal X-ray diffraction analysis. The cytotoxic activities of these compounds were carried out in vitro on human nasophyringeal carcinoma (CNE-2) and murine lymphocytic leukemia (P-388) tumor cell lines.