Geraniol is a monoterpenoid alcohol with various applications in food,cosmetics,and healthcare.Corynebacterium glutamicum is a potential platform for terpenoids production because it harbors the methylerythritol phosp...Geraniol is a monoterpenoid alcohol with various applications in food,cosmetics,and healthcare.Corynebacterium glutamicum is a potential platform for terpenoids production because it harbors the methylerythritol phosphate pathway.To engineer C.glutamicum to produce geraniol,two different truncated geraniol synthases (GESs) were respectively expressed,and strain LX02 expressing the truncated GESs from Valeriana officinalis (t Vo GES) produced 0.3 mg/L of geraniol.Then,three geranyl diphosphate synthases (GPPSs) were combinatorially co-expressed with t Vo GES to improve geraniol production.The amounts of produced geraniol were all higher than that produced by strain LX02.Strain LX03 co-expressing ERG20 F96W–N127W (ERG20 WW) and t Vo GES produced the highest amount,5.4 mg/L.Subsequently,the co-overexpression of1-deoxy-D-xylulose-5-phosphate synthase (dxs) and isopentenyl diphosphate isomerase (idi) further increased the production to 12.2 mg/L in strain LX03.Lastly,the production of geraniol was increased to 15.2 mg/L via fermentation optimization.To our knowledge,this is the first report on the engineering of C.glutamicum to produce geraniol and thus can serve as a reference for other monoterpenoid production studies.展开更多
Catharanthus roseus contains important anti-tumor terpenoid indole alkaloids (TIAs) such as vinblastine and vincristine. Cytochrome P450 enzyme geraniol 10-hydroxylase (G10H) is a putative rate-limiting enzyme involve...Catharanthus roseus contains important anti-tumor terpenoid indole alkaloids (TIAs) such as vinblastine and vincristine. Cytochrome P450 enzyme geraniol 10-hydroxylase (G10H) is a putative rate-limiting enzyme involved in the TIAs biosynthetic pathway in C. roseus. In this study the g10h gene driven by the cauliflower mosaic virus 35S (CaMV 35S) promoter was introduced into C. roseus through Agrobacterium-mediated transformation. The integration and overexpression of the target gene (g10h) in hairy root lines were confirmed by polymerase chain reaction and RT-QPCR analysis respectively. Overexpression of g10h in transgenic hairy root lines significantly enhanced the accumulations of monomeric alkaloid ajmalicine and dimeric alkaloids, vincristine and vinblastine. Total TIAs production in hairy roots reached (9.51) mg/g DW, over 3-fold higher than that in the untransformed root lines. This is the first report that engineering of g10h into TIAs-producing plant species results in significant enhancement of TIAs accumulation in cultured hairy roots. This study demonstrates that the putative rate-limiting step catalyzed by G10H is indeed the real rate-limiting step involved in the TIAs biosynthetic pathway in C. roseus, which is one of the key targets for promoting TIAs production by genetic engineering.展开更多
Terpenes are one of the largest and most diversified families of natural compounds. Although they have found numerous industrial applications, the molecular basis of their synthesis in plants has, until now, not been ...Terpenes are one of the largest and most diversified families of natural compounds. Although they have found numerous industrial applications, the molecular basis of their synthesis in plants has, until now, not been fully understood. Plant genomes have been shown to contain dozens of terpene synthase (TPS) genes, however knowledge of their amino-acidic protein sequence in not sufficient to predict which terpene(s) will be produced by a particular enzyme. In order to investigate the structural basis of a TPS specificity, we performed site directed mutations in the geraniol synthase from Ocimum basilicum. The results obtained suggest that a specific region on the catalytic site plays an important role in GPP transformation, either by stabilizing the GPP substrate on the catalytic site, or by enabling its transformation into a monoterpenol via an intermediate carbocation.展开更多
The reduction of geraniol to citronellol is the first step for the synthesis of natural phytol in the production of tocopherols and natural vitamin K.Baker's yeast was used in the bioreduction described above as a...The reduction of geraniol to citronellol is the first step for the synthesis of natural phytol in the production of tocopherols and natural vitamin K.Baker's yeast was used in the bioreduction described above as a whole-cell biocatalyst.However,the enzyme responsible for the reduction of geraniol to citronellol is not yet known.Four old yellow enzyme(OYE)genes were cloned from yeast and plants,and expressed in Escherichia coli for a high level of recombinant proteins.The recombinant protein displayed a catalytic activity of converting geraniol to citronellol as a sole product verified by GC-MS analyses.The recombinant OYE2 intact cells were found to show 3.7 and 1.9-fold higher activity than that of yeast cells and the recombinant crude extracts,respectively.Compared to the recombinant fusion enzyme,the entrokinase-cleaved enzyme displayed nearly identical activity for geraniol reduction.To our knowledge,this is the first enzyme identified to catalyze the formation of citronellol from geraniol by reducing the allylic alcohol double bond,which is normally known as inactivating group for the old yellow enzymes.展开更多
Geraniol is an acyclic monoterpenoid compound,which exists widely in aromatic plants.Geraniol has antibacterial and anti-inflammatory effects.Recently,it has been found that geraniol has a strong effect on improving i...Geraniol is an acyclic monoterpenoid compound,which exists widely in aromatic plants.Geraniol has antibacterial and anti-inflammatory effects.Recently,it has been found that geraniol has a strong effect on improving immune function and anti-tumor.Many experimental evidences support that geraniol has a good effect on the treatment or prevention of different types of tumors,such as breast cancer,lung cancer,liver cancer,pancreatic cancer,colon cancer,prostate cancer,etc.it also has a synergistic anti-cancer effect with many anti-cancer drugs,revealing the mechanism of its more complex anti-tumor pharmacological action System.In this review,we summarized a variety of anti-cancer signaling pathways and targets.Geraniol is considered to be a safe,effective and promising multi-target anti-cancer drug,which is expected to become an important force in the anti-cancer of traditional Chinese medicine.展开更多
采用液相质谱联用仪LC-MS、气相质谱联用仪GC-MS分析不同茶树品种、不同组织器官、不同时间香叶醇及其糖苷含量的变化,结果显示:香叶基樱草糖苷在中国变种(Camellia sinensis var. sinensis)中的含量显著高于阿萨姆变种(C.sinensis var....采用液相质谱联用仪LC-MS、气相质谱联用仪GC-MS分析不同茶树品种、不同组织器官、不同时间香叶醇及其糖苷含量的变化,结果显示:香叶基樱草糖苷在中国变种(Camellia sinensis var. sinensis)中的含量显著高于阿萨姆变种(C.sinensis var. assamica)。香叶基樱草糖苷在茶树幼嫩叶片中含量最高,在根中的含量最低,总体表现出嫩叶>茎>花>根。3月份茶树嫩梢中的香叶醇积累量最高,随着月份的增加而逐渐降低。在祁门红茶加工过程中,香叶基樱草糖苷含量在揉捻阶段显著降低。黄山地区6个品种红茶中,皖茶4号红茶中的香叶醇含量最高;6个品种红茶茶汤中香叶醇的气味活性值(OAV)均>1,分布范围3.93~28.38。Pearson相关性分析显示,有7个萜类合成酶候选基因表达量与香叶基樱草糖苷含量变化呈显著相关。本研究结果为进一步探究香叶醇积累差异成因及形成机制提供理论参考。展开更多
基金supported by the National Natural Science Foundation of China (No. 21878220)。
文摘Geraniol is a monoterpenoid alcohol with various applications in food,cosmetics,and healthcare.Corynebacterium glutamicum is a potential platform for terpenoids production because it harbors the methylerythritol phosphate pathway.To engineer C.glutamicum to produce geraniol,two different truncated geraniol synthases (GESs) were respectively expressed,and strain LX02 expressing the truncated GESs from Valeriana officinalis (t Vo GES) produced 0.3 mg/L of geraniol.Then,three geranyl diphosphate synthases (GPPSs) were combinatorially co-expressed with t Vo GES to improve geraniol production.The amounts of produced geraniol were all higher than that produced by strain LX02.Strain LX03 co-expressing ERG20 F96W–N127W (ERG20 WW) and t Vo GES produced the highest amount,5.4 mg/L.Subsequently,the co-overexpression of1-deoxy-D-xylulose-5-phosphate synthase (dxs) and isopentenyl diphosphate isomerase (idi) further increased the production to 12.2 mg/L in strain LX03.Lastly,the production of geraniol was increased to 15.2 mg/L via fermentation optimization.To our knowledge,this is the first report on the engineering of C.glutamicum to produce geraniol and thus can serve as a reference for other monoterpenoid production studies.
基金Item supported by China national"863"high-tech program (2002AA212191)China ministry of educa-tion and science and technology commission of Shanghai(04XD14011)
文摘Catharanthus roseus contains important anti-tumor terpenoid indole alkaloids (TIAs) such as vinblastine and vincristine. Cytochrome P450 enzyme geraniol 10-hydroxylase (G10H) is a putative rate-limiting enzyme involved in the TIAs biosynthetic pathway in C. roseus. In this study the g10h gene driven by the cauliflower mosaic virus 35S (CaMV 35S) promoter was introduced into C. roseus through Agrobacterium-mediated transformation. The integration and overexpression of the target gene (g10h) in hairy root lines were confirmed by polymerase chain reaction and RT-QPCR analysis respectively. Overexpression of g10h in transgenic hairy root lines significantly enhanced the accumulations of monomeric alkaloid ajmalicine and dimeric alkaloids, vincristine and vinblastine. Total TIAs production in hairy roots reached (9.51) mg/g DW, over 3-fold higher than that in the untransformed root lines. This is the first report that engineering of g10h into TIAs-producing plant species results in significant enhancement of TIAs accumulation in cultured hairy roots. This study demonstrates that the putative rate-limiting step catalyzed by G10H is indeed the real rate-limiting step involved in the TIAs biosynthetic pathway in C. roseus, which is one of the key targets for promoting TIAs production by genetic engineering.
文摘Terpenes are one of the largest and most diversified families of natural compounds. Although they have found numerous industrial applications, the molecular basis of their synthesis in plants has, until now, not been fully understood. Plant genomes have been shown to contain dozens of terpene synthase (TPS) genes, however knowledge of their amino-acidic protein sequence in not sufficient to predict which terpene(s) will be produced by a particular enzyme. In order to investigate the structural basis of a TPS specificity, we performed site directed mutations in the geraniol synthase from Ocimum basilicum. The results obtained suggest that a specific region on the catalytic site plays an important role in GPP transformation, either by stabilizing the GPP substrate on the catalytic site, or by enabling its transformation into a monoterpenol via an intermediate carbocation.
基金This work was supported by grants from the Ministry of Science and Technology of China(2007CB108802)State Key Laboratory of Phytochemistry and Plant Resources in West China(P2008-ZZ16,P2009-ZZ02).
文摘The reduction of geraniol to citronellol is the first step for the synthesis of natural phytol in the production of tocopherols and natural vitamin K.Baker's yeast was used in the bioreduction described above as a whole-cell biocatalyst.However,the enzyme responsible for the reduction of geraniol to citronellol is not yet known.Four old yellow enzyme(OYE)genes were cloned from yeast and plants,and expressed in Escherichia coli for a high level of recombinant proteins.The recombinant protein displayed a catalytic activity of converting geraniol to citronellol as a sole product verified by GC-MS analyses.The recombinant OYE2 intact cells were found to show 3.7 and 1.9-fold higher activity than that of yeast cells and the recombinant crude extracts,respectively.Compared to the recombinant fusion enzyme,the entrokinase-cleaved enzyme displayed nearly identical activity for geraniol reduction.To our knowledge,this is the first enzyme identified to catalyze the formation of citronellol from geraniol by reducing the allylic alcohol double bond,which is normally known as inactivating group for the old yellow enzymes.
文摘Ferric chloride catalyzes the isomerization and cyclization of geraniol, linalool and nerol in acetonitrile giving a-terpineol in good to high yields.
文摘Geraniol is an acyclic monoterpenoid compound,which exists widely in aromatic plants.Geraniol has antibacterial and anti-inflammatory effects.Recently,it has been found that geraniol has a strong effect on improving immune function and anti-tumor.Many experimental evidences support that geraniol has a good effect on the treatment or prevention of different types of tumors,such as breast cancer,lung cancer,liver cancer,pancreatic cancer,colon cancer,prostate cancer,etc.it also has a synergistic anti-cancer effect with many anti-cancer drugs,revealing the mechanism of its more complex anti-tumor pharmacological action System.In this review,we summarized a variety of anti-cancer signaling pathways and targets.Geraniol is considered to be a safe,effective and promising multi-target anti-cancer drug,which is expected to become an important force in the anti-cancer of traditional Chinese medicine.
文摘采用液相质谱联用仪LC-MS、气相质谱联用仪GC-MS分析不同茶树品种、不同组织器官、不同时间香叶醇及其糖苷含量的变化,结果显示:香叶基樱草糖苷在中国变种(Camellia sinensis var. sinensis)中的含量显著高于阿萨姆变种(C.sinensis var. assamica)。香叶基樱草糖苷在茶树幼嫩叶片中含量最高,在根中的含量最低,总体表现出嫩叶>茎>花>根。3月份茶树嫩梢中的香叶醇积累量最高,随着月份的增加而逐渐降低。在祁门红茶加工过程中,香叶基樱草糖苷含量在揉捻阶段显著降低。黄山地区6个品种红茶中,皖茶4号红茶中的香叶醇含量最高;6个品种红茶茶汤中香叶醇的气味活性值(OAV)均>1,分布范围3.93~28.38。Pearson相关性分析显示,有7个萜类合成酶候选基因表达量与香叶基樱草糖苷含量变化呈显著相关。本研究结果为进一步探究香叶醇积累差异成因及形成机制提供理论参考。
