| 1. |
Changes in lipid composition under salinity conditions in halophilic archaea that synthesize C₂₀-C₂₅ diether "isomers". |
| 2. |
Pursuing biosynthetic intermediates of carbon ring compounds specific to thermophilic archaeal lipid cores. |
| 3. |
Formation and structure, mass fragmentation of fatty acid derivatives from the oxidation reaction of archaeal ether core lipid for a mimic of oxidation in sediment. |
| 4. |
山内敬明，＠モード ワトキンソン, 高度好塩性アーキア脂質コアのC25-C20アーキオール異性体ならびに類縁体の探査, 日本地球惑星科学連合2022年度大会, 2022.06, アーキアは全て，特徴的なイソプレノイド脂質コアであるアーキオール（C20イソプレノイドジエーテル）(１)を持つ。好塩性アーキアはC25イソプレノイドを一つ持つC25-C20 ジエーテル(２)を生産する[1]。Dawsonらは幾つかの超好塩性アーキアでは，１と２ およびその不飽和体が生産されることを報告した[2]。一方，Teixidorらは岩塩中には２の位置異性体である３の存在を報告している[3]。これら化合物（２と３）は高塩濃度環境の指標として利用できることが期待される。投稿者はDawsonの提唱する構造の不飽和体化合物の化学合成から彼らの提唱する化学構造ではない二重結合の位置が異なる異性体の存在を示唆する結果を報告した[4]。また２と３の化学合成からTeixidorらの報告している岩塩中のジエーテルが２と３の混合物であることを強く示唆する結果を得た[5]。
さて，２と３はエーテル結合の位置異性体であるが，３はこれまで培養微生物体からの検出例はなく常に２のみが存在するとされてきた[6]。そこで現在理研BRCにて得られる，高塩濃度環境や岩塩などから単離された菌株を分与いただき，その培養と分析から，本当に３は微生物にはないのか，また生産菌による不飽和化合物の存在とその構造の詳細解析が可能か調査を行なっており[7]，その経過を報告する。
コア脂質の調製に関し，ヒドロキシアーキオールの調製で用いられているアルカリ性加水分解[8]を用いることにより，様々な菌株においてわずかに不飽和アーキオールが存在することと，Halorhabdus utahensis (JCM 11049)には３およびその不飽和化合物がコア脂質として存在することが明らかとなった。ここには大きな問題があり，多くの場合脂質コアは酸性による加水分解による処理を経ているがそこで不飽和ジエーテル化合物を加水分解してしまっている可能性がある。そこで二重結合を一つ持つモデル4を調製し加水分解によって検討した。4は酸性条件で直ちに加水分解しモノエーテルを生じた。これはアルカリ性加水分解の重要性を示している。また２と３の共存は，岩塩の結果[3]（おそらく均等な程度存在）から考えると３の異性体がもっと存在しても良さそうであるが３を主成分とするのは現状１種のみである。ただ数種において微量に３が存在するようである。３をはっきり含むような菌株の探査を引き続き行うとともに，３（および２）の分解速度や異性化の可能性も化学合成した標準物質で検討する予定である。. |
| 5. |
山内 敬明, 高度好塩性アーキアの脂質コアのアーキオール類縁体の多様性の再発見, 日本地球惑星科学連合大会2020年度大会, 2020.07, アーキアは全て特徴的なイソプレノイド脂質コアであるアーキオール（C20イソプレノイドジエーテル）(１)を持っている。さらに好塩性アーキアはC25イソプレノイドを一つ持つC25-C20 ジエーテル(２)を生産する[1]。また近年Dawsonらは幾つかの超好塩性アーキアでは，１と２ およびその不飽和体が生産されることを報告した[2]。一方，Teixidorらは岩塩中には２の位置異性体である３の存在を報告している[3]。
投稿者はDawsonの提唱する構造の不飽和体化合物の化学合成から彼らの提唱する化学構造ではない二重結合の位置が異なる異性体の存在を示唆する結果を報告した[4]。また２と３の化学合成からTeixidorらの報告している岩塩中のジエーテルが２と３の混合物であることを強く示唆する結果を得た[5]。
さて，２と３はエーテル結合の位置異性体であるが，これまで培養微生物体からの検出例はなく常に２のみが存在するとされてきた。また私の予察的実験によると化学合成と微生物試料の比較から１，２とも微生物種から多様な割合の不飽和化合物が混在することを示唆する結果を得てきた。現在理研BRCにて得られる，特に高い塩濃度であるフィールド，岩塩などから単離された菌株を分与いただき，その培養と分析から，本当に３は微生物にはないのか，また生産菌による不飽和化合物の存在とその構造の詳細解析が可能か調査を行なっており，その途中経過を報告する。
結果現在６菌株の培養，脂質抽出と再分析を行なっており，さらにコア脂質の調製に関し，ヒドロキシアーキオールの調製で用いられているアルカリ性加水分解[6]を用いることにより，様々な菌株において不飽和アーキオールが存在することと，Halorhabdus utahensis (JCM 11049)には３およびその不飽和化合物がコア脂質として存在することが明らかとなった。これまでアーキオール関連化合物の多様性は１と２と少々の不飽和化合物の存在のみ示され，あまり多様ではないと思われてきたが，実際はかなりの多様性をもって存在していることがわかった。また現状培養微生物試料からの３の検出は初めてである。さらに網羅的分析を行う予定である。. |
| 6. |
The precise structure of “unsaturated” archaeol derivatives in the halophilic archaea lipid-core. |
| 7. |
山内敬明, 金子雅紀, メタン生成アーキアのコア脂質主成分2-ヒドロキシアーキオールのアルキル鎖側の水酸基の絶対立体配置決定, 日本地球惑星科学連合2019年度大会, 2019.05. |
| 8. |
山内 敬明, Reconsideration of the structure of archaeol derivative with different carbon number at the ethereal portion, Biomarkers and Molecular isotopes: International Workshop of Organic Geochemistry, 2016.07, Archaea has a characteristic lipid-core, archaeol. The structure of archaeol is those in which two C20-saturated isoprenoid are linked to glycerol by ether bond. Further, a characteristic diether lipid-core (C20-C25 diether (1)) is produced by halophilic archaea. The regiochemisty of the hydrocarbon bonded with glycerol had been determined. The C25 (long) hydrocarbon is linked with the C-2 of the glycerol[1][2]. Teixidor et al. showed that archaeol and 1 were existed in the halite[3]. However, several literature were founded here and there with the different regiochemical structure for the expression of 2 (inculding Teixidor’s report) instead of 1. Further, Dawson et al. showed the existence of several unsaturated isoprenoid diethers (such as tentative structure 3) in the lipid-core of several halophilic archaea which was incubated with very high salt concentration with the mass spectra of the TMS ether of 2 and 3[4].
During my experiments for the deterimination of the regiochemistry and carbon number of the hydrocarbon of the diether, the general chemical synthetic method for the unsymmetric diether was developed. Therefore, the unsymmetric diether 1, 2 and 3 were prepared in my experiments for the confirmation/determination of the structure of several diether reported at Dawson’s literature. Then, 1 , 2 and 3 were chemically synthesized according to the reported method of an intermadiate in the synthesis of archael tetraether[5]. 1) The analysis of the mass fragmentation of the TMS derivative, 1 and 2 were cleary different in mass fragmentation and the mass spectrum in Dawson’s report was revealed to the isomer 1. The structure of microbiological sample derived from halophilc archaea was confirmed as 1. 2) The compound 3 is different from the tentative structure of Dawson’s unsaturated diether. Synthesis of several different regioisomer of unsaturated chain and unsaturated positon were currntly underway. |
| 9. |
山内 敬明, Possibility of existence of unrevealed (new) halophilic archaea in halite or ancient hypersaline environment, Goldschmidt 2016, 2016.06,
Archaea has a characteristic lipid-core, archaeol. The structure of archaeol is those in which two C20-saturated isoprenoid are linked to glycerol by ether bond. Further, a characteristic diether (C25-C20 diether (1)) which is constructed from one C25 and one C20 isoprenoid is produced by halophilic archaea. The regiochemisty of the hydrocarbon bonded with glycerol had been determined[1],[2]. The C25 (long) hydrocarbon is linked with the C-2 of the glycerol. On the other hands, Teixidor et al. showed that archaeol and 1 were existed in the halite[3]. However, the different regiochemical structure 2 (C25 hydrocarbon was linked with the C-3 of the glycerol) for the structure of 1 were found in several literature (including lit. [3]).
During my experiments for the deterimination of the regiochemistry and carbon number of the hydrocarbon of the diether[4], the possibility of misreading of fragmentation analysis of 1 (2) in Teixidor’s report were suspected. Therefore, the two regioisomers of 1 and 2 were chemically prepared and fragmentation analysis were carried out.
Then, 1 and 2 were chemically synthesized according to the reported method of an intermadiate in the synthesis of archael tetraether[5]. The analysis of the mass fragmentation of the TMS derivative of 1 and 2, the mass spectrum in Teixidor’s report was revealed to the mixture of 1 and 2. It is suggested that the regiochemically different ether lipid were accumulated in the halite. Further, it is suggested that the unrevealed archaea which can biosynthesize regioisomeric C25-C20 diether in halite and/or in ancient hypersaline environment were existed.. |
| 10. |
Characteristic C20-C25 diether which is constructed from one C25 and one C20 isoprenoid is produced by halophilic archaea. The regiochemisty of the hydrocarbon bonded with glycerol is confirmed from the chemical synthesis of standard compound.. |
| 11. |
The 2- and 3-hydroxyarchaeol “equivalent” about the diastereomers at the hydroxyl group in the isoprenoidal portion were prepared stereoselectively. The stereochemistry at the hydroxyl group was induced with Katsuki-Sharpless epoxidation of phytol. Then, 2- and 3-hydroxyarchaeol were synthesized. About the gas chromatographic behavior of the 4 compounds, the absolute stereochemistry of the hydroxyl group is considered to be R at the moment. . |
| 12. |
For the investigation of the stereochemisrty of the hydroxyl group in the saturated isoprenoid of 2- and 3-hydroxyarchaeol, important biomarker for the existence of methanogenic archaea and anoxic oxidation of methane, the racemic equivalents were prepared and the properties of the 4 isomers mixture were investigated. Two separated gas chromatographic peaks were observed about the 2-hydroxyarchaeol equivalent. Further, (at least) the mixture of the two compounds was observed from the 13C NMR spectra. Thus, it is strongly suggested that natural 2-hydroxyarchaeol is a single isomer. On the other hands, single peak on gas chromatogram were observed in case of 3-hydroxyarchaeol, however, the mixture of the two compounds was observed from the 13C NMR spectra. Chiral preparation and determination of stereochemistry of the saturated isoprenoidal part and 2- and 3-hydroxyarchaeol will be presented.. |
| 13. |
YAMAUCHI Noriaki, IWAMOTO Yuya, Naraoka Hiroshi, Structural Changes of Humic Acids Isolated from the Chikugo River Sediments, The 9th Asia Pacific Conference on Sustainable Energy & Environmental Technologies, 2013.07. |
| 14. |
YAMAUCHI Noriaki, Physiological Studies and Analytical Method for the Core-Lipid of Halophilic Archaea, TH 2nd International Congress on Natural Sciences, 2012.10. |
| 15. |
YAMAUCHI Noriaki, IWAMOTO Yuya, Naraoka Hiroshi, Structural Changes of Humic Acids Extracted from Estuarine Sediments in Several North Kyushu Fields, The 2nd International Congress on Natural Sciences, 2012.10. |
| 16. |
Chemical Preparation of Hydroxyarchaeol Equivalent. |
| 17. |
Biosynthetic pathway of L-gulose, a rare sugar existed in the main polar lipid of a ther- mophilic archaea. |
| 18. |
Development of environmental indicator of coastal and estuarial region from several analysis of humic acid fraction extracted from the corresponding surface sediment. |
| 19. |
Development of environmental indicator of coastal and estuarial region from several analysis of humic acid fraction extracted from the corresponding surface sediment. |
| 20. |
Relation of C20-C20 and C25-C20 Diether Lipid Contents of Halophilic Archaea and Several Environmental Conditions, and Precise GC-MS Analysis of Diether-type Lipid and Relative Compounds. |
| 21. |
Leucine-mevalonate shunt pathway in halophilic archaea: stereochemistry of putative isovaleryl-CoA dehydrogenase. |
| 22. |
Leucine-Mevalonate pathway in halophilic archaea: Incorporation and stereospecific conversion of diastereotopic methyl group of leucine to isoprenoidal lipid in Halobacterium halobium. |
| 23. |
Analysis of intermediates in biosynthetic pathway of calditol in the thermophilic archaea, Sulfolobus acidocaldarius. |
| 24. |
Possibilities of C25-C20 diether, the lipid core characteristic for halophlic archaea, toward a new biomarker
-Lipid contents of halophilic archaea for various conditions-. |
| 25. |
Relation of Coastal Environments and Structural Features of Humic Substances at Sone Tideland
at the North of Kyushu. |
| 26. |
Attempt to evaluate the environment of the coastal region with the structural feature of humic acid extracted from the surface sediment. |
| 27. |
Possibility of substrate promiscuity and involvement of catalytic oxidoreduction at "cyclization" enzyme of calditol carbocycle from glucose in Sulfolobus acidcaldarius. |
| 28. |
Consideration of seasonal variation of the constituents of humic acid at the surface sediment of estuarine region in Japan and evaluation of coastal humic acid by UV spectra. |
| 29. |
Central Metabolism and Glycerol Metabolism of Sulfolobus, a major part of Theromophilic Archaea. |
| 30. |
Consideration of seasonal and regional variation of the constituents of humic acid at the surface sediment of estuarine region in Japan. |
| 31. |
Characteristics of Carbohydrate Metabolism and Evolution of Archaea from the Studies of the Biosynthesis of Peculiar Carbocycle in the Polar Lipid of Theromophilic Archaea. |
| 32. |
Consideration of seasonal variation of the constituents of humic acid at the surface sediment of estuarine region with regional differences. |
| 33. |
Biosynthesis of calditol, a characteristic carbocyclic compound in the lipid of thermophilic archaea. |
| 34. |
Mechanistic Implicatiuon of the cyclization of Glucose to Calditol, a characteristic carbocyclic compound in the lipid of thermophilic archaea. |
| 35. |
Evaluation, Differentiation, and Structural Studies of Humic Acid from Estuarine Sediment at Coastal Region in Different Fields. |
| 36. |
Structural Evaluation of Humic Acids from Estuarine Sediment at Coastal Region of North-Kyushu. |
| 37. |
Biosynthesis of calditol, a characteristic carbocyclic compound in the lipid of thermoacidophilic archaea. |
| 38. |
Structural Studies and Evaluation of Humic Acids from Estuarine Sediment at Coastal Region of Ariake-Sea and Hakata-Bay. |
| 39. |
Evaluation and Structural Studies of Humic Acid from Estuarine Sediment at Coastal Ariake-Sea. |
| 40. |
Analysis of Humic Acids in the Sediment of the Downstream of Rivers and Tidelands in Kyushu. |
| 41. |
Correlation of Isoprenoidal Lipid Biosynthesis and Lysine Metabolism in Themoacidophilic and Halophilic Archaea. |
| 42. |
Correlation of Lysine Metabolism and Isoprenoid Biosynthesis in Halophilic Archaea. |
| 43. |
Charactaristics of Isoprenoidal Lipid Biosynthesis in Archaea Compared with the "Usual" Organisms toward the First Living Cell in Earth. |
| 44. |
Improved Synthesis of Chrally Deuterium-Labeled Leucine at the Diastereotopic Terminal Methyl Groups. |
| 45. |
Correlation of Isoprenoidal Lipid Biosynthesis and Lysine Metabolism in Halophilic Archaea. |
| 46. |
Correlation of Isoprenoidal Lipid Biosynthesis and Amino Acid Metabolism in Halophilic Archaea and Charactaristics and Diversities of Archaeal Lipid Structure. |
| 47. |
Reinvestigations of Isoprenoidal Lipid Biosynthesis in Halophilic Archaea. |
| 48. |
2-Deocy-scyllo-inosose synthase in Bacillus circulans (3) - Purification and Charactaristics-. |
| 49. |
Antitumor Activites of Oligosacharides from the Extract of Sunflower against Transplant Tumor of Mice. |
