The key enzymes involved in the flavonoid biosynthesis pathway have been extensively studied in seed plants,but relatively less in ferns.In this study,two 4-Coumarate:coenzyme A ligases(Sc4CL1 and Sc4CL2)and one novel...The key enzymes involved in the flavonoid biosynthesis pathway have been extensively studied in seed plants,but relatively less in ferns.In this study,two 4-Coumarate:coenzyme A ligases(Sc4CL1 and Sc4CL2)and one novel chalcone synthase(ScCHS1)were functionally characterized by mining the Stenoloma chusanum transcriptome database.Recombinant Sc4CLs were able to esterify various hydroxycinnamic acids to corresponding acyl-coenzyme A(CoA).ScCHS1could catalyze p-coumaroyl-CoA,cinnamoyl-CoA,caffeoyl-CoA,and feruloyl-CoA to form naringenin,pinocembrin,eriodictyol,and homoeriodictyol,respectively.Moreover,enzymatic kinetics studies revealed that the optimal substrates of ScCHS1were feruloyl-CoA and caffeoyl-CoA,rather than p-coumaroyl-CoA,which was substantially different from the common CHSs.Crystallographic and sitedirected mutagenesis experiments indicated that the amino acid residues,Leu87,Leu97,Met165,and Ile200,located in the substrate-binding pocket near the B-ring of products,could exert a significant impact on the unique catalytic activity of ScCHS1.Furthermore,overexpression of ScCHS1 in tt4 mutants could partially rescue the mutant phenotypes.Finally,ScCHS1 and Sc4CL1 were used to synthesize flavanones and flavones with multi-substituted hydroxyl and methoxyl B-ring in Escherichia coli,which can effectively eliminate the need for the cytochrome P450 hydroxylation/O-methyltransferase from simple phenylpropanoid acids.In summary,the identification of these important Stenoloma enzymes provides a springboard for the future production of various flavonoids in E.coli.展开更多
To study the chemical constituents of Stenoloma chusana.The compounds were isolated and purified by recrystallization and various chromatographic techniques.The structures were elucidated by chemical evidence and spec...To study the chemical constituents of Stenoloma chusana.The compounds were isolated and purified by recrystallization and various chromatographic techniques.The structures were elucidated by chemical evidence and spectroscopi methods.five compounds were obtained and identified as(1)hexacosanoic acid,(2)3-hydroxy-heptacosanol,(3)phthalic acid bis-(2-ethylhexyl)ester,(4)β-sitosterol,(5)daucosterol.The five compounds were isolated from this genus for the first time.展开更多
The second speciation of eight trace elements（Zn,Cr,Mg,Mn,Cu,Fe,Ni and Ca）in Stenoloma chusana（L.）Ching were studied.The aqueous solution of the traditional Chinese herbal was separated into the dissolved and part...The second speciation of eight trace elements（Zn,Cr,Mg,Mn,Cu,Fe,Ni and Ca）in Stenoloma chusana（L.）Ching were studied.The aqueous solution of the traditional Chinese herbal was separated into the dissolved and particulate forms by means of 0.45μm membrane filter.The dissolved form was determined as free ions and non-free ions,organic and inorganic,stable and labile forms by means of cation exchange resin,CHCl3 and D-411 Chelating resin.The results showed that the content of eight elements in particulate are far more than that in dissolved.The contents of free ions form of Zn,Ca and Mg are more than 75%.Mn hasn’t any free ions form.Cu、Fe and Ni exist on mostly non-free ions form.The content of free ions form of Cr is 54.23%.Eight elements exist on mostly inorganic forms after extraction of CHCl3.After the separation of D-411 Chelating resin,the content of Zn in labile form is 62.82%.The contents of else elements in stable form are higher than those in labile form and Ni hasn’t any labile form.展开更多
Contents of total flavonoids in above-ground part of Stenoloma chusanum(L.) Ching collected from different production regions were analyzed.The results showed that total flavonoid content in above-ground part of S.chu...Contents of total flavonoids in above-ground part of Stenoloma chusanum(L.) Ching collected from different production regions were analyzed.The results showed that total flavonoid content in above-ground part of S.chusanum collected from Qiubei of Yunnan Province was the highest,reached to 127.461 mg·g-1,and could keep the high content after transplanted to Nanjing of Jiangsu Province.The total flavonoid content in leaf blade was obviously higher than that in leaf stalk.It is suggested that S.chusanum from Qiubei is an excellent resources and the leaf blade of S.chusanum should be used mainly.展开更多
基金supported by the National Natural Science Foundation of China (No. 31770330 and 31870720)supported by the Foundation of Youth Innovation Promotion Association of the Chinese Academy of Sciences
文摘The key enzymes involved in the flavonoid biosynthesis pathway have been extensively studied in seed plants,but relatively less in ferns.In this study,two 4-Coumarate:coenzyme A ligases(Sc4CL1 and Sc4CL2)and one novel chalcone synthase(ScCHS1)were functionally characterized by mining the Stenoloma chusanum transcriptome database.Recombinant Sc4CLs were able to esterify various hydroxycinnamic acids to corresponding acyl-coenzyme A(CoA).ScCHS1could catalyze p-coumaroyl-CoA,cinnamoyl-CoA,caffeoyl-CoA,and feruloyl-CoA to form naringenin,pinocembrin,eriodictyol,and homoeriodictyol,respectively.Moreover,enzymatic kinetics studies revealed that the optimal substrates of ScCHS1were feruloyl-CoA and caffeoyl-CoA,rather than p-coumaroyl-CoA,which was substantially different from the common CHSs.Crystallographic and sitedirected mutagenesis experiments indicated that the amino acid residues,Leu87,Leu97,Met165,and Ile200,located in the substrate-binding pocket near the B-ring of products,could exert a significant impact on the unique catalytic activity of ScCHS1.Furthermore,overexpression of ScCHS1 in tt4 mutants could partially rescue the mutant phenotypes.Finally,ScCHS1 and Sc4CL1 were used to synthesize flavanones and flavones with multi-substituted hydroxyl and methoxyl B-ring in Escherichia coli,which can effectively eliminate the need for the cytochrome P450 hydroxylation/O-methyltransferase from simple phenylpropanoid acids.In summary,the identification of these important Stenoloma enzymes provides a springboard for the future production of various flavonoids in E.coli.
文摘To study the chemical constituents of Stenoloma chusana.The compounds were isolated and purified by recrystallization and various chromatographic techniques.The structures were elucidated by chemical evidence and spectroscopi methods.five compounds were obtained and identified as(1)hexacosanoic acid,(2)3-hydroxy-heptacosanol,(3)phthalic acid bis-(2-ethylhexyl)ester,(4)β-sitosterol,(5)daucosterol.The five compounds were isolated from this genus for the first time.
文摘The second speciation of eight trace elements（Zn,Cr,Mg,Mn,Cu,Fe,Ni and Ca）in Stenoloma chusana（L.）Ching were studied.The aqueous solution of the traditional Chinese herbal was separated into the dissolved and particulate forms by means of 0.45μm membrane filter.The dissolved form was determined as free ions and non-free ions,organic and inorganic,stable and labile forms by means of cation exchange resin,CHCl3 and D-411 Chelating resin.The results showed that the content of eight elements in particulate are far more than that in dissolved.The contents of free ions form of Zn,Ca and Mg are more than 75%.Mn hasn’t any free ions form.Cu、Fe and Ni exist on mostly non-free ions form.The content of free ions form of Cr is 54.23%.Eight elements exist on mostly inorganic forms after extraction of CHCl3.After the separation of D-411 Chelating resin,the content of Zn in labile form is 62.82%.The contents of else elements in stable form are higher than those in labile form and Ni hasn’t any labile form.
文摘Contents of total flavonoids in above-ground part of Stenoloma chusanum(L.) Ching collected from different production regions were analyzed.The results showed that total flavonoid content in above-ground part of S.chusanum collected from Qiubei of Yunnan Province was the highest,reached to 127.461 mg·g-1,and could keep the high content after transplanted to Nanjing of Jiangsu Province.The total flavonoid content in leaf blade was obviously higher than that in leaf stalk.It is suggested that S.chusanum from Qiubei is an excellent resources and the leaf blade of S.chusanum should be used mainly.
