The existence of multigenic families in the mevalonate pathway suggests divergent functional roles for pathway components involved in the biosynthesis of plant sterols. Squalene epoxidases （SQEs） are key components ...The existence of multigenic families in the mevalonate pathway suggests divergent functional roles for pathway components involved in the biosynthesis of plant sterols. Squalene epoxidases （SQEs） are key components of this pathway, and Squalene Epoxidase 1 （SQE1） has been identified as a fundamental enzyme in this biosynthetic step. In the present work, we extended the characterization of the remaining SQE family members, phylogenetically resolving between true SQEs and a subfamily of SQE-like proteins that is exclusive to Brassicaceae. Functional characterization of true SQE family members, Squalene Epox- idase 2 （SQE2） and Squalene Epoxidase 3 （SQE3）, indicates that SQE3, but not SQE2, contributes to the bulk SQE activity in Arabidopsis, with sqe3-1 mutants accumulating squalene and displaying sensitivity to ter- binafine. We genetically demonstrated that SQE3 seems to play a particularly significant role in embryo development. Also, SQE1 and SQE3 both localize in the endoplasmic reticulum, and SQE3 can functionally complement SQEI. Thus, SQE1 and SQE3 seem to be two functionally unequal redundant genes in the pro- motion of plant SQE activity in Arabidopsis.展开更多
Objective In plant, squalene epoxidase （SE） catalyzes the first oxygenation step in the biosynthetic pathway of triterpenoid and phytosterol, representing one of the rate-limiting enzymes in this pathway. Bupleurum ...Objective In plant, squalene epoxidase （SE） catalyzes the first oxygenation step in the biosynthetic pathway of triterpenoid and phytosterol, representing one of the rate-limiting enzymes in this pathway. Bupleurum chinense is an important medicinal herb with its major active constituents such as triterpenoid saponins and saikosaponins. In order to obtain the series of enzymatic genes involved in saikosaponin biosynthesis, a cDNA of SE, designated BcSEI, was cloned from B. chinense. Methods The BcSEI gene was cloned by homology-based PCR and 5＇/3＇ RACE methods from the adventitious roots of B. chinense. The physical and chemical parameters of BcSE1 protein were predicted by protparam. In order to discover hints in amino acid sequences on the dominant functions in the biosynthesis of saponin or phytosterol, sequences of SE from other plants were downloaded from NCBI for sequences alignment and phylogenetic analysis. BcSEI was cloned into a yeast mutant KLNI （MATa, ergl.＇：URA3, leu2, ura3, and trpl） to verify the enzyme activity of BcSE1. Additionally, the tissue-specific expression and methyl jasmonate （MeJA） inducibility of BcSEI were investigated using quantitative real-time PCR. Results The predicted protein of BcSE1 is highly similar to SEs from other plants sharing amino acid sequence identities of up to 88%. The BcSEI can functionally complement with yeast SE gene （ERGI） when expressed in the KLNI mutant （MATa, ergl：：URA3, leu2, ura3, and trpl）. Using as controls with ^-amyrin synthase （G-AS） which is presumed to catalyze the first committed step in saikosaponin biosynthesis and a cycloartenol synthase （CAS） relating to the phytosterol biosynthesis, the transcript of BcSE1 was significantly elevated by MeJA in adventitious roots of B. chinenseand the transcript of BcSElwas most abundant in the fruits and flowers of plants, followed by that in the leaves and roots, and least in stems. Conclusion It is the first time to illustrate the molecular information of SE in B. ch展开更多
Background:Colorectal cancer(CRC)is one of the most malignant tumorswith high incidence,yet its molecular mechanism is not fully understood,hindering the development of targeted therapy.Metabolic abnormalities are a h...Background:Colorectal cancer(CRC)is one of the most malignant tumorswith high incidence,yet its molecular mechanism is not fully understood,hindering the development of targeted therapy.Metabolic abnormalities are a hallmark of cancer.Targeting dysregulated metabolic features has become an important direction for modern anticancer therapy.In this study,we aimed to identify a new metabolic enzyme that promotes proliferation of CRC and to examine the related molecular mechanisms.Methods:We performed RNA sequencing and tissue microarray analyses of human CRC samples to identify new genes involved in CRC.Squalene epoxidase(SQLE)was identified to be highly upregulated in CRC patients.The regulatory function of SQLE in CRC progression and the therapeutic effect of SQLE inhibitors were determined by measuring CRC cell viability,colony and organoid formation,intracellular cholesterol concentration and xenograft tumor growth.Themolecularmechanism of SQLE functionwas explored by combining transcriptome and untargeted metabolomics analysis.Western blotting and realtime PCR were used to assess MAPK signaling activation by SQLE.Results:SQLE-related control of cholesterol biosynthesis was highly upregulated in CRC patients and associated with poor prognosis.SQLE promoted CRC growth in vitro and in vivo.Inhibition of SQLE reduced the levels of calcitriol(active form of vitamin D3)and CYP24A1,followed by an increase in intracellular Ca2+concentration.Subsequently,MAPK signaling was suppressed,resulting in the inhibition of CRC cell growth.Consistently,terbinafine,an SQLE inhibitor,suppressed CRC cell proliferation and organoid and xenograft tumor growth.Conclusions:Our findings demonstrate that SQLE promotes CRC through the accumulation of calcitriol and stimulation of CYP24A1-mediated MAPK signaling,highlighting SQLE as a potential therapeutic target for CRC treatment.展开更多
Background:Lung squamous cell carcinoma(Lusc)lacks effective targeted therapies and has a poor prognosis.Disruption of squalene epoxidase(SQLE)has been implicated in metabolic disorders and cancer.However,the role of ...Background:Lung squamous cell carcinoma(Lusc)lacks effective targeted therapies and has a poor prognosis.Disruption of squalene epoxidase(SQLE)has been implicated in metabolic disorders and cancer.However,the role of SQLE as a monooxygenase involved in oxidativestressremainsunclear.Methods:We analyzed the expression and prognosis of lung adenocarcinoma(LUAD)and LUSC samples from GEO and TCGA databases.The proliferative activity of the tumors after intervention of SQLE was verified by cell and animal experiments.JC-1 assay,flow cytometry,and Western blot were used to show changes in apoptosis after intervention of sQLE.Flow cytometry and fluorescence assay of ROs levels were used to indicate oxidative stress status.Results:We investigated the unique role of SQLE expression in the diagnosis and prognosis prediction of LUSC.Knockdown of SQLE or treatment with the SQLE inhibitor terbinafine can suppress the proliferation of LUsC cells by inducing apoptosis and reactive oxygen species accumulation.However,depletion of SQLE also results in the impairment of lipid peroxidation and ferroptosis resistance such as upregulation of glutathione peroxidase 4.Therefore,prevention of SQLE in synergy with glutathione peroxidase 4 inhibitor RSL3 effectively mitigates the proliferation and growth of LUSC.Conclusion:Our study indicates that the low expression of sQLE employs adaptive survival through regulating the balance of apoptosis and ferroptosis resistance.In future,the combinational therapy of targeting sQLE and ferroptosis could be a promising approach in treating LUSC.展开更多
Panax ginseng C.A.Mey.is an important plant species used in traditional Chinese medicine,whose primary active ingredient is a ginsenoside.Ginsenoside biosynthesis is not only regulated by transcription factors but als...Panax ginseng C.A.Mey.is an important plant species used in traditional Chinese medicine,whose primary active ingredient is a ginsenoside.Ginsenoside biosynthesis is not only regulated by transcription factors but also controlled by a variety of structural genes.Nonetheless,the molecular mechanism underlying ginsenoside biosynthesis has always been a topic in the discussion of ginseng secondary metabolites.Squalene epoxidase(SQE)is a key enzyme in the mevalonic acid pathway,which affects the biosynthesis of secondary metabolites such as terpenoid.Using ginseng transcriptome,expression,and ginsenoside content databases,this study employed bioinformatic methods to systematically analyze the genes encoding SQE in ginseng.We first selected six PgSQE candidates that were closely involved in ginsenoside biosynthesis and then identified PgSQE08-01 to be highly associated with ginsenoside biosynthesis.Next,we constructed the overexpression vector pCAMBIA3301-PgSQE08-01 and the RNAi vector pART27-PgSQE08-01 and transformed ginseng adventitious roots using Agrobacterium rhizogenes,to obtain positive hairy-root clones.Thereafter,quantitative reverse transcriptionpolymerase chain reaction and high-performance liquid chromatography were used to determine the expression of relevant genes and ginsenoside content,respectively.Then,we focused on the function of PgSQE08-01 gene,which was noted to be involved in ginsenoside biosynthesis.Thus,these findings not only provided a molecular basis for the identification of important functional genes in ginseng but also enriched genetic resources for the biosynthesis of ginsenosides using synthetic biology.展开更多
To assess the sublethal toxicity of the herbicide acetochlor to earthworms and to find out biomarkers possible inducted under acetochlor exposure, Eiseniafetida was exposed to artificial soils supplemented with differ...To assess the sublethal toxicity of the herbicide acetochlor to earthworms and to find out biomarkers possible inducted under acetochlor exposure, Eiseniafetida was exposed to artificial soils supplemented with different concentrations of acetochlor（5, 10, 20, 40 and 80 mg/kg soil）. Effects of the acetochlor on cytochrome P450 monooxygenases p-nitroanisole O-demethylase（ODM）, aldrin epoxidase（AE） and glutathione-S-transferases （GSTs） activities were determined. The results revealed cytochrome P450 monooxygenases were elevated with increasing concentrations of acetochlor, and the AE activity increased significantly compared with control at the concentration of 80 mg/kg （P〈0.05）. However, ODM activity from E. fetida was not induced significantly by acetochlor at all treatments（P〉0.05）. Sodium dodecyl sulfate-polyacryamide gel electrophoresis（SDS-PAGE） showed that one protein band was visualized and no evident differences were found in protein profiles between treatments and control. The GST activity increased significantly with longer duration（P〈0.05） and increasing concentrations of acetochlor exposure（P〈0.05）. This study showed that the monooxygenases and GSTs activities in E. fetida could be induced by acetochlor, and thus, the AE and GST could be used in sublethal assays for soil contamination surveys and GST could be used as biomarkers of acetochlor exposure in E. fetida.展开更多
Objectives Aspidin BB, a typical phloroglucinol derivative from Dryopteris fragrans, possesses significant antifungal property. This study aimed to investigate potential mechanism of antifungal activity of Aspidin BB ...Objectives Aspidin BB, a typical phloroglucinol derivative from Dryopteris fragrans, possesses significant antifungal property. This study aimed to investigate potential mechanism of antifungal activity of Aspidin BB against Trichophyton rubrum which is the most common pathogens responsible for chronic dermatophytosis. Methods The minimum inhibitory concentration （MIC） ofAspidin BB against strains was determined by broth microdilution. The effects of Aspidin BB on ergosterol biosynthesis were investigated by content determination based on UPLC method. Besides, the effects of drugs on squalene epoxidase （SE） in T. rubrum cell membrane were analyzed. Results MIC value of Aspidin BB against T. rubrum was 25.0 IJg/mL. Aspidin BB reduced ergosterol content significantly, but no notable effect on squalene epoxidase activity. Conclusion The results suggested that Aspidin BB inhibited ergosterol biosynthesis. However, it was not squalene epoxidase but other components may sever as possible targets in ergosterol biosynthesis pathway.展开更多
Objective： Light quality has effect on the accumulation of gypenosides in the medicinal plant Gynosternma pentaphyllum in the family Cucurbitaceae, while the squalene synthase （SS） and squalene epoxidase （SE） are...Objective： Light quality has effect on the accumulation of gypenosides in the medicinal plant Gynosternma pentaphyllum in the family Cucurbitaceae, while the squalene synthase （SS） and squalene epoxidase （SE） are the key enzymes for gypenoside biosynthesis, The objective of this study was to elucidate the rela- tionship between light quality and biosynthesis key enzyme involving the regulation of gypenoside accu- mulation. Methods： The content of total gypenosides was measured by colorimetric method and the expression of SS and SE gene was determined by quantitative Real-time PCR in the seedlings of G. pentaphyllum which were grown with different light quality. Results： Light quality showed remarkable impacts on the accumulation of total gypenosides. The highest content of total gypenosides in the plant under red light condition was determined, followed by blue light and white light, while the lowest content was recorded under dark condition, qRT-PCR analysis proved that the expression levels of SS and SE genes were also affected by light quality. The high-level gene expressions of SS and SE were found in the plant under red light condition, followed by blue light, with the least content in darkness. The statistical analysis revealed that the total gypenosides were significantly different in different light treatment and the content of total gypenosides was positively related to the expression of SS and SE genes. Conclusions： Light quality regulates gypenoside accumulation via altering the expression of SS and SE in G. pentaphyllum.展开更多
Lesion mimic mutants(LMMs) are advantageous materials for studying programmed cell death(PCD).Although some rice LMM genes have been cloned, the diversity of functions of these genes indicates that the mechanism of ce...Lesion mimic mutants(LMMs) are advantageous materials for studying programmed cell death(PCD).Although some rice LMM genes have been cloned, the diversity of functions of these genes indicates that the mechanism of cell death regulation in LMMs needs further study. In this study, we identified a rice light-dependent leaf lesion mimic mutant 4(llm4) that showed abnormal chloroplast structure, photoinhibition, reduced photosynthetic protein levels, massive accumulation of reactive oxygen species(ROS), and PCD. Map-based cloning and complementation testing revealed that LLM4 encodes zeaxanthin epoxidase(ZEP), an enzyme involved in the xanthophyll cycle, which functions in plant photoprotection,ROS scavenging, and carotenoid and abscisic acid(ABA) biosynthesis. The ABA content was decreased,and the contents of 24 carotenoids differed between the llm4 mutant and the wild type(WT). The llm4mutant showed reduced dormancy and greater sensitive to ABA than the WT. We concluded that the mutation of LLM4 resulted in the failure of xanthophyll cycle, in turn causing ROS accumulation. The excessive ROS accumulation damaged chloroplast structure and induced PCD, leading eventually to the formation of lesion mimics.展开更多
Reducing losses caused by pathogens is an effective strategy for stabilizing crop yields.Daunting challenges remain in cloning and characterizing genes that inhibit stripe rust,a devastating disease of wheat(Triticum ...Reducing losses caused by pathogens is an effective strategy for stabilizing crop yields.Daunting challenges remain in cloning and characterizing genes that inhibit stripe rust,a devastating disease of wheat(Triticum aestivum)caused by Puccinia striiformis f.sp.tritici(Pst).We found that suppression of wheat zeaxanthin epoxidase 1(ZEP1)increased wheat defense against Pst.We isolated the yellow rust slower 1(yrs1)mutant of tetraploid wheat in which a premature stop mutation in ZEP1-B underpins the phenotype.Genetic analyses revealed increased H_(2)O_(2) accumulation in zep1 mutants and demonstrated a correlation between ZEP1 dysfunction and slower Pst growth in wheat.Moreover,wheat kinase START 1.1(WKS1.1,Yr36)bound,phosphorylated,and suppressed the biochemical activity of ZEP1.A rare natural allele in the hexaploid wheat ZEP1-B promoter reduced its transcription and Pst growth.Our study thus identified a novel suppressor of Pst,characterized its mechanism of action,and revealed beneficial variants for wheat disease control.This work opens the door to stacking wheat ZEP1 variants with other known Pst resistance genes in future breeding programs to enhance wheat tolerance to pathogens.展开更多
文摘The existence of multigenic families in the mevalonate pathway suggests divergent functional roles for pathway components involved in the biosynthesis of plant sterols. Squalene epoxidases （SQEs） are key components of this pathway, and Squalene Epoxidase 1 （SQE1） has been identified as a fundamental enzyme in this biosynthetic step. In the present work, we extended the characterization of the remaining SQE family members, phylogenetically resolving between true SQEs and a subfamily of SQE-like proteins that is exclusive to Brassicaceae. Functional characterization of true SQE family members, Squalene Epox- idase 2 （SQE2） and Squalene Epoxidase 3 （SQE3）, indicates that SQE3, but not SQE2, contributes to the bulk SQE activity in Arabidopsis, with sqe3-1 mutants accumulating squalene and displaying sensitivity to ter- binafine. We genetically demonstrated that SQE3 seems to play a particularly significant role in embryo development. Also, SQE1 and SQE3 both localize in the endoplasmic reticulum, and SQE3 can functionally complement SQEI. Thus, SQE1 and SQE3 seem to be two functionally unequal redundant genes in the pro- motion of plant SQE activity in Arabidopsis.
基金Open Research Fund of State Key Laboratory Breeding Base of Systematic Research,Development and Utilization of Chinese Medicine Resources 2014KFJJ05
文摘Objective In plant, squalene epoxidase （SE） catalyzes the first oxygenation step in the biosynthetic pathway of triterpenoid and phytosterol, representing one of the rate-limiting enzymes in this pathway. Bupleurum chinense is an important medicinal herb with its major active constituents such as triterpenoid saponins and saikosaponins. In order to obtain the series of enzymatic genes involved in saikosaponin biosynthesis, a cDNA of SE, designated BcSEI, was cloned from B. chinense. Methods The BcSEI gene was cloned by homology-based PCR and 5＇/3＇ RACE methods from the adventitious roots of B. chinense. The physical and chemical parameters of BcSE1 protein were predicted by protparam. In order to discover hints in amino acid sequences on the dominant functions in the biosynthesis of saponin or phytosterol, sequences of SE from other plants were downloaded from NCBI for sequences alignment and phylogenetic analysis. BcSEI was cloned into a yeast mutant KLNI （MATa, ergl.＇：URA3, leu2, ura3, and trpl） to verify the enzyme activity of BcSE1. Additionally, the tissue-specific expression and methyl jasmonate （MeJA） inducibility of BcSEI were investigated using quantitative real-time PCR. Results The predicted protein of BcSE1 is highly similar to SEs from other plants sharing amino acid sequence identities of up to 88%. The BcSEI can functionally complement with yeast SE gene （ERGI） when expressed in the KLNI mutant （MATa, ergl：：URA3, leu2, ura3, and trpl）. Using as controls with ^-amyrin synthase （G-AS） which is presumed to catalyze the first committed step in saikosaponin biosynthesis and a cycloartenol synthase （CAS） relating to the phytosterol biosynthesis, the transcript of BcSE1 was significantly elevated by MeJA in adventitious roots of B. chinenseand the transcript of BcSElwas most abundant in the fruits and flowers of plants, followed by that in the leaves and roots, and least in stems. Conclusion It is the first time to illustrate the molecular information of SE in B. ch
基金National Natural Science Foundation of China,Grant/Award Numbers:31630047,81874201,81725014Natural Science Foundation of Shanghai,Grant/AwardNumber:20ZR1452300+1 种基金Shanghai Municipal Health Bureau,Grant/Award Number:201840359The National Key Research and Development Program of China,Grant/Award Numbers:2020YFA0509000,2017YFA0503600。
文摘Background:Colorectal cancer(CRC)is one of the most malignant tumorswith high incidence,yet its molecular mechanism is not fully understood,hindering the development of targeted therapy.Metabolic abnormalities are a hallmark of cancer.Targeting dysregulated metabolic features has become an important direction for modern anticancer therapy.In this study,we aimed to identify a new metabolic enzyme that promotes proliferation of CRC and to examine the related molecular mechanisms.Methods:We performed RNA sequencing and tissue microarray analyses of human CRC samples to identify new genes involved in CRC.Squalene epoxidase(SQLE)was identified to be highly upregulated in CRC patients.The regulatory function of SQLE in CRC progression and the therapeutic effect of SQLE inhibitors were determined by measuring CRC cell viability,colony and organoid formation,intracellular cholesterol concentration and xenograft tumor growth.Themolecularmechanism of SQLE functionwas explored by combining transcriptome and untargeted metabolomics analysis.Western blotting and realtime PCR were used to assess MAPK signaling activation by SQLE.Results:SQLE-related control of cholesterol biosynthesis was highly upregulated in CRC patients and associated with poor prognosis.SQLE promoted CRC growth in vitro and in vivo.Inhibition of SQLE reduced the levels of calcitriol(active form of vitamin D3)and CYP24A1,followed by an increase in intracellular Ca2+concentration.Subsequently,MAPK signaling was suppressed,resulting in the inhibition of CRC cell growth.Consistently,terbinafine,an SQLE inhibitor,suppressed CRC cell proliferation and organoid and xenograft tumor growth.Conclusions:Our findings demonstrate that SQLE promotes CRC through the accumulation of calcitriol and stimulation of CYP24A1-mediated MAPK signaling,highlighting SQLE as a potential therapeutic target for CRC treatment.
基金the National Natural Science Foundation of China(Grant No.92159302,W.L.)Science and Technology Project of Sichuan(Grant No.2022ZDZX0018,W.L.)+6 种基金1.3.5 project for disciplines of excellence,West China Hospital,Sichuan University(Grant No.ZYGD22009,W.L.)National Key R&D program of China(Grant No.2022YFC2505000)NSFC general program(Grant No.82272796)NSFC special program(Grant No.82241229)CAMS Innovation Fund for Medical Sciences(Grant No.CIFMS 2022-I2M-1-009)CAMS Key Laboratory of Translational Research on Lung Cancer(Grant No.2018PT31035)the Aiyou foundation(Grant No.KY201701).
文摘Background:Lung squamous cell carcinoma(Lusc)lacks effective targeted therapies and has a poor prognosis.Disruption of squalene epoxidase(SQLE)has been implicated in metabolic disorders and cancer.However,the role of SQLE as a monooxygenase involved in oxidativestressremainsunclear.Methods:We analyzed the expression and prognosis of lung adenocarcinoma(LUAD)and LUSC samples from GEO and TCGA databases.The proliferative activity of the tumors after intervention of SQLE was verified by cell and animal experiments.JC-1 assay,flow cytometry,and Western blot were used to show changes in apoptosis after intervention of sQLE.Flow cytometry and fluorescence assay of ROs levels were used to indicate oxidative stress status.Results:We investigated the unique role of SQLE expression in the diagnosis and prognosis prediction of LUSC.Knockdown of SQLE or treatment with the SQLE inhibitor terbinafine can suppress the proliferation of LUsC cells by inducing apoptosis and reactive oxygen species accumulation.However,depletion of SQLE also results in the impairment of lipid peroxidation and ferroptosis resistance such as upregulation of glutathione peroxidase 4.Therefore,prevention of SQLE in synergy with glutathione peroxidase 4 inhibitor RSL3 effectively mitigates the proliferation and growth of LUSC.Conclusion:Our study indicates that the low expression of sQLE employs adaptive survival through regulating the balance of apoptosis and ferroptosis resistance.In future,the combinational therapy of targeting sQLE and ferroptosis could be a promising approach in treating LUSC.
基金This work was supported by an award from the Department of Science and Technology of Jilin Province(20210402043GH and 20210204063YY).
文摘Panax ginseng C.A.Mey.is an important plant species used in traditional Chinese medicine,whose primary active ingredient is a ginsenoside.Ginsenoside biosynthesis is not only regulated by transcription factors but also controlled by a variety of structural genes.Nonetheless,the molecular mechanism underlying ginsenoside biosynthesis has always been a topic in the discussion of ginseng secondary metabolites.Squalene epoxidase(SQE)is a key enzyme in the mevalonic acid pathway,which affects the biosynthesis of secondary metabolites such as terpenoid.Using ginseng transcriptome,expression,and ginsenoside content databases,this study employed bioinformatic methods to systematically analyze the genes encoding SQE in ginseng.We first selected six PgSQE candidates that were closely involved in ginsenoside biosynthesis and then identified PgSQE08-01 to be highly associated with ginsenoside biosynthesis.Next,we constructed the overexpression vector pCAMBIA3301-PgSQE08-01 and the RNAi vector pART27-PgSQE08-01 and transformed ginseng adventitious roots using Agrobacterium rhizogenes,to obtain positive hairy-root clones.Thereafter,quantitative reverse transcriptionpolymerase chain reaction and high-performance liquid chromatography were used to determine the expression of relevant genes and ginsenoside content,respectively.Then,we focused on the function of PgSQE08-01 gene,which was noted to be involved in ginsenoside biosynthesis.Thus,these findings not only provided a molecular basis for the identification of important functional genes in ginseng but also enriched genetic resources for the biosynthesis of ginsenosides using synthetic biology.
文摘To assess the sublethal toxicity of the herbicide acetochlor to earthworms and to find out biomarkers possible inducted under acetochlor exposure, Eiseniafetida was exposed to artificial soils supplemented with different concentrations of acetochlor（5, 10, 20, 40 and 80 mg/kg soil）. Effects of the acetochlor on cytochrome P450 monooxygenases p-nitroanisole O-demethylase（ODM）, aldrin epoxidase（AE） and glutathione-S-transferases （GSTs） activities were determined. The results revealed cytochrome P450 monooxygenases were elevated with increasing concentrations of acetochlor, and the AE activity increased significantly compared with control at the concentration of 80 mg/kg （P〈0.05）. However, ODM activity from E. fetida was not induced significantly by acetochlor at all treatments（P〉0.05）. Sodium dodecyl sulfate-polyacryamide gel electrophoresis（SDS-PAGE） showed that one protein band was visualized and no evident differences were found in protein profiles between treatments and control. The GST activity increased significantly with longer duration（P〈0.05） and increasing concentrations of acetochlor exposure（P〈0.05）. This study showed that the monooxygenases and GSTs activities in E. fetida could be induced by acetochlor, and thus, the AE and GST could be used in sublethal assays for soil contamination surveys and GST could be used as biomarkers of acetochlor exposure in E. fetida.
基金Application-oriented Research Project of Guangdong Provincial Department of Science and Technology(2015B020234009)Traditional Chinese Medicine Industry Research Project of State Administration of Traditional Chinese Medicine of People’s Republic of China(201507004)
文摘Objectives Aspidin BB, a typical phloroglucinol derivative from Dryopteris fragrans, possesses significant antifungal property. This study aimed to investigate potential mechanism of antifungal activity of Aspidin BB against Trichophyton rubrum which is the most common pathogens responsible for chronic dermatophytosis. Methods The minimum inhibitory concentration （MIC） ofAspidin BB against strains was determined by broth microdilution. The effects of Aspidin BB on ergosterol biosynthesis were investigated by content determination based on UPLC method. Besides, the effects of drugs on squalene epoxidase （SE） in T. rubrum cell membrane were analyzed. Results MIC value of Aspidin BB against T. rubrum was 25.0 IJg/mL. Aspidin BB reduced ergosterol content significantly, but no notable effect on squalene epoxidase activity. Conclusion The results suggested that Aspidin BB inhibited ergosterol biosynthesis. However, it was not squalene epoxidase but other components may sever as possible targets in ergosterol biosynthesis pathway.
基金financially supported by the National Natural Science Foundation of China (31760044,31260039)Key Course of Hunan Province (Ecology),Jishou University (2015005)
文摘Objective： Light quality has effect on the accumulation of gypenosides in the medicinal plant Gynosternma pentaphyllum in the family Cucurbitaceae, while the squalene synthase （SS） and squalene epoxidase （SE） are the key enzymes for gypenoside biosynthesis, The objective of this study was to elucidate the rela- tionship between light quality and biosynthesis key enzyme involving the regulation of gypenoside accu- mulation. Methods： The content of total gypenosides was measured by colorimetric method and the expression of SS and SE gene was determined by quantitative Real-time PCR in the seedlings of G. pentaphyllum which were grown with different light quality. Results： Light quality showed remarkable impacts on the accumulation of total gypenosides. The highest content of total gypenosides in the plant under red light condition was determined, followed by blue light and white light, while the lowest content was recorded under dark condition, qRT-PCR analysis proved that the expression levels of SS and SE genes were also affected by light quality. The high-level gene expressions of SS and SE were found in the plant under red light condition, followed by blue light, with the least content in darkness. The statistical analysis revealed that the total gypenosides were significantly different in different light treatment and the content of total gypenosides was positively related to the expression of SS and SE genes. Conclusions： Light quality regulates gypenoside accumulation via altering the expression of SS and SE in G. pentaphyllum.
基金the financial support of the National Natural Science Foundation of China (32060454, 32272109)Hainan Yazhou Bay Seed Laboratory (B21HJ0215)+1 种基金National Natural Science Foundation of China (32072048, U2004204)Specific Research Fund of The Innovation Platform for Academicians of Hainan Province。
文摘Lesion mimic mutants(LMMs) are advantageous materials for studying programmed cell death(PCD).Although some rice LMM genes have been cloned, the diversity of functions of these genes indicates that the mechanism of cell death regulation in LMMs needs further study. In this study, we identified a rice light-dependent leaf lesion mimic mutant 4(llm4) that showed abnormal chloroplast structure, photoinhibition, reduced photosynthetic protein levels, massive accumulation of reactive oxygen species(ROS), and PCD. Map-based cloning and complementation testing revealed that LLM4 encodes zeaxanthin epoxidase(ZEP), an enzyme involved in the xanthophyll cycle, which functions in plant photoprotection,ROS scavenging, and carotenoid and abscisic acid(ABA) biosynthesis. The ABA content was decreased,and the contents of 24 carotenoids differed between the llm4 mutant and the wild type(WT). The llm4mutant showed reduced dormancy and greater sensitive to ABA than the WT. We concluded that the mutation of LLM4 resulted in the failure of xanthophyll cycle, in turn causing ROS accumulation. The excessive ROS accumulation damaged chloroplast structure and induced PCD, leading eventually to the formation of lesion mimics.
基金supported by the National Key Research and Development Program(2022YFF1001501)the National Natural Science Foundation of China(31972350)+1 种基金the Chinese Universities Scientific Fund(2022TC174)the financial support from an open project of the State Key Laboratory of Crop Stress Adaptation and Improvement in Henan University.
文摘Reducing losses caused by pathogens is an effective strategy for stabilizing crop yields.Daunting challenges remain in cloning and characterizing genes that inhibit stripe rust,a devastating disease of wheat(Triticum aestivum)caused by Puccinia striiformis f.sp.tritici(Pst).We found that suppression of wheat zeaxanthin epoxidase 1(ZEP1)increased wheat defense against Pst.We isolated the yellow rust slower 1(yrs1)mutant of tetraploid wheat in which a premature stop mutation in ZEP1-B underpins the phenotype.Genetic analyses revealed increased H_(2)O_(2) accumulation in zep1 mutants and demonstrated a correlation between ZEP1 dysfunction and slower Pst growth in wheat.Moreover,wheat kinase START 1.1(WKS1.1,Yr36)bound,phosphorylated,and suppressed the biochemical activity of ZEP1.A rare natural allele in the hexaploid wheat ZEP1-B promoter reduced its transcription and Pst growth.Our study thus identified a novel suppressor of Pst,characterized its mechanism of action,and revealed beneficial variants for wheat disease control.This work opens the door to stacking wheat ZEP1 variants with other known Pst resistance genes in future breeding programs to enhance wheat tolerance to pathogens.
