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Chunjiang Wang - One of the best experts on this subject based on the ideXlab platform.
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Anomalous Hopane distributions at the Permian-Triassic boundary, Meishan, China - : Evidence for the end-Permian marine ecosystem collapse
Organic Geochemistry, 2007Co-Authors: Chunjiang WangAbstract:Abstract Molecular and carbon isotopic geochemistry of Hopanes in marine sediments of the Meishan section in Changxing County, Zhejiang Province of China, were studied to reveal biotic and environmental changes across the Permian–Triassic boundary (PTB) and the Wuchiapingian–Changhsingian boundary (WCB). The Hopane distribution at the PTB is characterized by high ratios of moretane/Hopane, Tm/Ts, Tm/C 30 Hopane, C 31 /C 32 Hopane and Hopane/sterane. This Hopane distribution is anomalous for these marine sediments, but it is typical of coal measure strata and soils. Two possible genetic mechanisms for such an anomaly are suggested: (1) these Hopanes were terrigenous and most probably originated from acidified soil and peat. This mechanism implies that the marine primary production and aerobic bacteria production at the PTB were extremely low. (2) This Hopane distribution was possibly caused by freshening and acidification of the upper water column during the end-Permian to Early Triassic marine stagnation and stratification. This Hopane anomaly, which coincides with the end-Permian mass extinction and carbon-isotope excursion, may signal the end-Permian mass extinctions and marine and terrigenous ecosystem collapse. The 13 C-enriched Hopanes with the fingerprint of typical anoxic marine shales, coupled with an n -C 15 – n -C 17 -dominated distribution of n -alkanes, strongly indicate that the organic matter around the WCB at Meishan originated mainly from cyanobacteria. The corresponding positive δ 13 C carbonate , and higher total organic carbon and hydrocarbon index (HI) values, strongly suggest that high marine primary production and marine anoxia caused by intermittent cyanobacterial blooms, resulted in the local mass extinction at Meishan.
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anomalous Hopane distributions at the permian triassic boundary meishan china evidence for the end permian marine ecosystem collapse
Organic Geochemistry, 2007Co-Authors: Chunjiang WangAbstract:Abstract Molecular and carbon isotopic geochemistry of Hopanes in marine sediments of the Meishan section in Changxing County, Zhejiang Province of China, were studied to reveal biotic and environmental changes across the Permian–Triassic boundary (PTB) and the Wuchiapingian–Changhsingian boundary (WCB). The Hopane distribution at the PTB is characterized by high ratios of moretane/Hopane, Tm/Ts, Tm/C 30 Hopane, C 31 /C 32 Hopane and Hopane/sterane. This Hopane distribution is anomalous for these marine sediments, but it is typical of coal measure strata and soils. Two possible genetic mechanisms for such an anomaly are suggested: (1) these Hopanes were terrigenous and most probably originated from acidified soil and peat. This mechanism implies that the marine primary production and aerobic bacteria production at the PTB were extremely low. (2) This Hopane distribution was possibly caused by freshening and acidification of the upper water column during the end-Permian to Early Triassic marine stagnation and stratification. This Hopane anomaly, which coincides with the end-Permian mass extinction and carbon-isotope excursion, may signal the end-Permian mass extinctions and marine and terrigenous ecosystem collapse. The 13 C-enriched Hopanes with the fingerprint of typical anoxic marine shales, coupled with an n -C 15 – n -C 17 -dominated distribution of n -alkanes, strongly indicate that the organic matter around the WCB at Meishan originated mainly from cyanobacteria. The corresponding positive δ 13 C carbonate , and higher total organic carbon and hydrocarbon index (HI) values, strongly suggest that high marine primary production and marine anoxia caused by intermittent cyanobacterial blooms, resulted in the local mass extinction at Meishan.
Yu Qi - One of the best experts on this subject based on the ideXlab platform.
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organic matter provenance and depositional environment of marine to continental mudstones and coals in eastern ordos basin china evidence from molecular geochemistry and petrology
International Journal of Coal Geology, 2020Co-Authors: Leon Bowen, Kun Yu, Yiwen Ju, Yu Qi, Cheng Huang, Weilai ZhangAbstract:Abstract Cyclothems, composed of interbedded mudstone, coal and sandstone layers, make up the Taiyuan and Shanxi Formations in the Late Carboniferous to Early Permian in North China under a marine-to-continental depositional environment. The cyclothems act as important fossil energy hosts, such as coalbeds, hydrocarbon source rocks and unconventional natural gas reservoirs. Organic geochemistry and petrology of mudstones and coals in the Taiyuan and Shanxi Formations in the eastern Ordos Basin were studied to reveal the organic matter sources and paleoenvironments. Total organic carbon (TOC) contents vary from 1.1 wt% (mudstone) to 72.6 wt% (coal). The samples are mainly within the oil window, with the Tmax values ranging from 433 to 469 °C. Organic petrology and source biomarkers indicate that the mudstones were sourced from a mixed organic matter input, and terrigenous organic matter predominates over aquatic organic matter. The coals are mostly sourced by terrigenous organic matter inputs. High concentrations of Hopanes argue for a strong bacterial input. Some m/z 217 mass chromatograms have peaks at the Hopanes' retention times as a result of high Hopane to sterane ratios. These Hopane-derived peaks do not interfere the identification of the steranes because the Hopanes and the steranes have different retention times. Maturity-dependent biomarkers demonstrate that the samples have been thermally mature, which agree with the Tmax values. Anomalously low C29 20S/(20S + 20R) and C29 ββ/(ββ + αα) sterane ratios are present in all the samples, and are interpreted as due to the terrigenous organic matter input or the coal-related depositional environment. In addition, biomarkers and iron sulfide morphology indicate that the organic matter of the mudstones deposited in a proximal setting with shallow, brackish/fresh water bodies. With consideration of preservation of organic matter, the redox conditions are dysoxic. Redox oscillations resulted in the records of oxic conditions in some samples. Finally, the coals and the mudstones mainly generate gas and have poor oil generative potential.
Yanlong Yang - One of the best experts on this subject based on the ideXlab platform.
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characterization and biosynthesis of a rare fungal Hopane type triterpenoid glycoside involved in the antistress property of aspergillus fumigatus
Organic Letters, 2019Co-Authors: Peng Zhang, Nancy P Keller, Yanlong YangAbstract:A rare fungal Hopane-type triterpenoid glycoside fumihopaside A was identified by genome mining in combination with HPLC–MS/MS in Aspergillus fumigatus. Combining genetic deletions in A. fumigatus with heterologous reconstitutions in Aspergillus nidulans of the afum gene cluster, we identified one fungal squalene Hopane cyclase AfumA charging the cyclization of the hopene skeleton, one cytochrome P450, and one UDP-glycosyltransferase. Bioassays indicated that fumihopaside A plays important roles in protecting A. fumigatus against heat or ultraviolet stress.
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Characterization and Biosynthesis of a Rare Fungal Hopane-Type Triterpenoid Glycoside Involved in the Antistress Property of Aspergillus fumigatus
2019Co-Authors: Peng Zhang, Nancy P Keller, Yanlong Yang, Qiaoqiao Tao, Wen-bing Yin, Hongwei LiuAbstract:A rare fungal Hopane-type triterpenoid glycoside fumihopaside A was identified by genome mining in combination with HPLC–MS/MS in Aspergillus fumigatus. Combining genetic deletions in A. fumigatus with heterologous reconstitutions in Aspergillus nidulans of the afum gene cluster, we identified one fungal squalene Hopane cyclase AfumA charging the cyclization of the hopene skeleton, one cytochrome P450, and one UDP-glycosyltransferase. Bioassays indicated that fumihopaside A plays important roles in protecting A. fumigatus against heat or ultraviolet stress
Weilai Zhang - One of the best experts on this subject based on the ideXlab platform.
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organic matter provenance and depositional environment of marine to continental mudstones and coals in eastern ordos basin china evidence from molecular geochemistry and petrology
International Journal of Coal Geology, 2020Co-Authors: Leon Bowen, Kun Yu, Yiwen Ju, Yu Qi, Cheng Huang, Weilai ZhangAbstract:Abstract Cyclothems, composed of interbedded mudstone, coal and sandstone layers, make up the Taiyuan and Shanxi Formations in the Late Carboniferous to Early Permian in North China under a marine-to-continental depositional environment. The cyclothems act as important fossil energy hosts, such as coalbeds, hydrocarbon source rocks and unconventional natural gas reservoirs. Organic geochemistry and petrology of mudstones and coals in the Taiyuan and Shanxi Formations in the eastern Ordos Basin were studied to reveal the organic matter sources and paleoenvironments. Total organic carbon (TOC) contents vary from 1.1 wt% (mudstone) to 72.6 wt% (coal). The samples are mainly within the oil window, with the Tmax values ranging from 433 to 469 °C. Organic petrology and source biomarkers indicate that the mudstones were sourced from a mixed organic matter input, and terrigenous organic matter predominates over aquatic organic matter. The coals are mostly sourced by terrigenous organic matter inputs. High concentrations of Hopanes argue for a strong bacterial input. Some m/z 217 mass chromatograms have peaks at the Hopanes' retention times as a result of high Hopane to sterane ratios. These Hopane-derived peaks do not interfere the identification of the steranes because the Hopanes and the steranes have different retention times. Maturity-dependent biomarkers demonstrate that the samples have been thermally mature, which agree with the Tmax values. Anomalously low C29 20S/(20S + 20R) and C29 ββ/(ββ + αα) sterane ratios are present in all the samples, and are interpreted as due to the terrigenous organic matter input or the coal-related depositional environment. In addition, biomarkers and iron sulfide morphology indicate that the organic matter of the mudstones deposited in a proximal setting with shallow, brackish/fresh water bodies. With consideration of preservation of organic matter, the redox conditions are dysoxic. Redox oscillations resulted in the records of oxic conditions in some samples. Finally, the coals and the mudstones mainly generate gas and have poor oil generative potential.
Peng Zhang - One of the best experts on this subject based on the ideXlab platform.
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characterization and biosynthesis of a rare fungal Hopane type triterpenoid glycoside involved in the antistress property of aspergillus fumigatus
Organic Letters, 2019Co-Authors: Peng Zhang, Nancy P Keller, Yanlong YangAbstract:A rare fungal Hopane-type triterpenoid glycoside fumihopaside A was identified by genome mining in combination with HPLC–MS/MS in Aspergillus fumigatus. Combining genetic deletions in A. fumigatus with heterologous reconstitutions in Aspergillus nidulans of the afum gene cluster, we identified one fungal squalene Hopane cyclase AfumA charging the cyclization of the hopene skeleton, one cytochrome P450, and one UDP-glycosyltransferase. Bioassays indicated that fumihopaside A plays important roles in protecting A. fumigatus against heat or ultraviolet stress.
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Characterization and Biosynthesis of a Rare Fungal Hopane-Type Triterpenoid Glycoside Involved in the Antistress Property of Aspergillus fumigatus
2019Co-Authors: Peng Zhang, Nancy P Keller, Yanlong Yang, Qiaoqiao Tao, Wen-bing Yin, Hongwei LiuAbstract:A rare fungal Hopane-type triterpenoid glycoside fumihopaside A was identified by genome mining in combination with HPLC–MS/MS in Aspergillus fumigatus. Combining genetic deletions in A. fumigatus with heterologous reconstitutions in Aspergillus nidulans of the afum gene cluster, we identified one fungal squalene Hopane cyclase AfumA charging the cyclization of the hopene skeleton, one cytochrome P450, and one UDP-glycosyltransferase. Bioassays indicated that fumihopaside A plays important roles in protecting A. fumigatus against heat or ultraviolet stress
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A new Hopane triterpenoid from Saxiglossum angustissimum
Chinese Chemical Letters, 2008Co-Authors: Zhi Hong Zhong, Peng Zhang, Han-li Ruan, Yong Hui ZhangAbstract:Abstract A new Hopane triterpenoid, Hopane 22, 29-diol-29-formate ( 1 ), has been isolated from the whole herbs of Saxiglossum angustissimum (Gies.) Ching and its structure has been successfully determined on the basis of spectroscopic evidences.