The optimized color space is searched by using the wavelet scattering network in the KTH_TIPS_COL color image database for image texture classification. The effect of choosing the color space on the classification acc...The optimized color space is searched by using the wavelet scattering network in the KTH_TIPS_COL color image database for image texture classification. The effect of choosing the color space on the classification accuracy is investigated by converting red green blue (RGB) color space to various other color spaces. The results show that the classification performance generally changes to a large degree when performing color texture classification in various color spaces, and the opponent RGB-based wavelet scattering network outperforms other color spaces-based wavelet scattering networks. Considering that color spaces can be changed into each other, therefore, when dealing with the problem of color texture classification, converting other color spaces to the opponent RGB color space is recommended before performing the wavelet scattering network.展开更多
Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hyb...Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hybridization bands detected by a repetitive sequence probe, rTRS, were mapped to the ends of all the four chromosomes. Two or three of the bands detected by each of the other 12 probes were also mapped to different chromosomes. The bands detected by the same probe usually occurred in similar locations of different chromosomes. Loci detected by different DNA probes were often similarly arranged on different chromosomes. Chromosomes 8 and 9 showed colinearity of marker loci arrangement indicating a possible common origin. A segment on chromosome 9 was also very similar to the previously reported duplicated fragments on the ends of chromosomes 11 and 12 which were also detected in this study, indicating a likely common origin. Moreover, the various degrees of distributional similarity of the segments suggest a complex relationship among the chromosomes in the evolution of the rice genome. These results support the proposition that chromosome duplication and diversification may be a mechanism for the origin and evolution of the chromosomes in the rice genome.展开更多
In 2000 and 2001, 1-year-old seedlings of 7 economic tree species including chestnut, apricot, persimmon, peach, walnut, pear and apple were cultured in garden pots that had a diameter of 40 cm and were filled with cl...In 2000 and 2001, 1-year-old seedlings of 7 economic tree species including chestnut, apricot, persimmon, peach, walnut, pear and apple were cultured in garden pots that had a diameter of 40 cm and were filled with clean sand. The major components of exudates released from their roots were isolated and analysed by GC-MS. Totally 200 kinds of organic chemicals were isolated, of which 3 kinds i.e. naphthalene, dimethylbenzene and dibutyl phthalate were principally controlled pollutants according to 'Blacklist of Principal Environment Pollutants in China' and the standard of U.S. Environmental Protection Agency (EPA). The research result provided theoretical evidence for selecting low-pollution economic forest crops in the water source protection area in Miyun Reservoir.展开更多
Polyphenols from the ethanol extracts of Sargassum tenerrimum (ST) with potent antiallergic effects were studied to optimize separation process through column chromatography. The adsorption and desorption characteri...Polyphenols from the ethanol extracts of Sargassum tenerrimum (ST) with potent antiallergic effects were studied to optimize separation process through column chromatography. The adsorption and desorption characteristics of three widely used adsorbents: macroporous resin, silica gel, and polyvinylpolypyrrolidone (PVPP), were critically evaluated respectively and studied for the optimization of preparative separation of polyphenols. Static operations on these adsorbents showed that macroporous resin had the best adsorption and desorption capability among the three adsorbents. Dynamic adsorption and desorption with macroporous resin packed column were also conducted to optimize the parameters such as: with the optimal values shown in brackets, the concen- tration of extract solution (4 times diluted), pH value (6-7), adsorption speed (3BVh-1, bed volumes/per hour), concentration of ethanol (80%), elution speed (3 BV ht) and elution volume (7 BV). The chromatographic process so optimized gave a purity of 62.43% from the crude polyphenols, providing a promising basis for large scale preparation of bioactive polyphenols upon further scaling up tests.展开更多
Objective To explore the molecular targets and associated potential pathways of Lycii Fructus(LF,Gou Qi Zi,枸杞子)in the treatment of retinitis pigmentosa(RP)by the approaches of network pharmacology and bioinformatic...Objective To explore the molecular targets and associated potential pathways of Lycii Fructus(LF,Gou Qi Zi,枸杞子)in the treatment of retinitis pigmentosa(RP)by the approaches of network pharmacology and bioinformatics.Methods The potential blood-entry active ingredients and targets of LF were retrieved by Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP).RP-related gene targets were retrieved through disease comprehensive databases.Protein-protein interaction(PPI)network of LF component-targets and RP disease-targets was constructed by STRING,and the intersection of the 2 networks was extracted.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis of theintersection network were conducted by Database for Annotation,Visualization and Integrated Discovery(DAVID).CytoHubba was used to screen the key targets.Results A total of 188 chemical constituents related to LF was retrieved from TCMSP database.45 active ingredients were screened according to pharmacokinetic parameters oral bioavailability(OB)and drug similarity(DL).36 active ingredients were further screened and 201 targets related to these constituents were obtained.206 target genes directly related to RP were obtained from the disease comprehensive databases,and 89 genes were obtained from the intersection of componenttarget and disease-target PPI network.These genes were mainly involved in intracellular signal transduction,GTPase activity regulation,cell morphology regulation,and other biological processes.Molecular functions were mainly related to Rho guanine nucleotide exchange factor activity,GTPase activator activity,receptor signal protein serine/threonine kinase activity and so on.They were enriched in the cytoplasm,cell membrane,Golgi apparatus,and other regions.The mechanism was related to cell cycle pathways,neurotrophin signaling pathways,Ras signaling pathways,and so on.10 key gene targets of LF in the treatment of RP were screened.Conclusions The material basis for LF to exert its pharmacodynamic effect is 36 active ingredients such as cycloartenol,mandenol,and so on.The key targets of LF in the treatment of RP include 10 genes,such as Rho,PAK,and so on.The main mechanism is related to the regulation of the Ras signaling pathway,neurotrophin signaling pathway,cell cycle related pathway,and other signaling networks.展开更多
Five tryptophan analogues with a hydrophobic indole ring and an amino group on each molecule were used as functional ligands of mixed-mode resins for human serum albumin(HSA) purification. Their adsorption performance...Five tryptophan analogues with a hydrophobic indole ring and an amino group on each molecule were used as functional ligands of mixed-mode resins for human serum albumin(HSA) purification. Their adsorption performance was evaluated and the effects of p H and salt addition on HSA adsorption were studied. The resins prepared showed typical p H-dependent adsorption and the highest adsorption capacity and affinity were found at pH 5.0for all the resins tested. The saturated adsorption capacity was 138.02 mg·g^(-1)with the tryptaminefunctionalized resin, which significantly decreased at p H below 4.0 due to electrostatic repulsion between ligands and HSA. Moreover, the addition of Na Cl or(NH_4)_2SO_4in media reduced HSA adsorption capacity, although the two salts showed different affecting profiles. The tryptamine-functionalized resin showed the best salt-tolerant performance, and its high adsorption capacity was maintained under high salt concentrations. In addition, the five resins prepared showed good adsorption selectivity for recombinant HSA from Pichia pastoris broth. Molecular docking results between tryptamine and HSA indicated that tryptamine was favorable to bind on Site II(indole-binding site) of HSA.展开更多
Classical methyl-CpG binding proteins contain the conserved DNA binding motif methyl-cytosine binding domain(MBD), which preferentially binds to methylated CpG dinucleotides. These proteins serve as transcriptional re...Classical methyl-CpG binding proteins contain the conserved DNA binding motif methyl-cytosine binding domain(MBD), which preferentially binds to methylated CpG dinucleotides. These proteins serve as transcriptional repressors,mediating gene silencing via DNA cytosine methylation. Mutations in methyl-CpG binding protein 2 (MeCP2) have beenlinked to the human mental retardation disorder Rett syndrome, suggesting an important role for methyl-CpG bindingproteins in brain development and function. This mini-review summarizes the recent advances in studying the diversefunctions of MeCP2 as a prototype for other methyl-CpG binding proteins in the development and function of thevertebrate nervous system.展开更多
Malignant melanoma, characterized by invasive local growth and early formation of metastases, is the most aggressive type of skin cancer. Melanoma inhibitory activity (MIA), secreted by malignant melanoma cells, int...Malignant melanoma, characterized by invasive local growth and early formation of metastases, is the most aggressive type of skin cancer. Melanoma inhibitory activity (MIA), secreted by malignant melanoma cells, interacts with the cell adhesion receptors, integrins a4131 and 05131, facilitating cell detachment and promoting formation of me- tastases. In the present study, we demonstrate that MIA secretion is confined to the rear end of migrating cells, while in non-migrating cells MIA accumulates in the actin cortex. MIA protein takes a conventional secretory pathway including coat protein complex I (COPI)- and coat protein complex II (COPII)-dependent protein transport to the cell periphery, where its final release depends on intracellular Ca2+ ions. Interestingly, the Ca2+-activated K+-channel, subfamily N, member 4 (KCa3.1), known to be active at the rear end of migrating cells, was found to support MIA secretion. Secretion was diminished by the specific KCa3.1 channel inhibitor TRAM-34 and by expression of dominant- negative mutants of the channel. In summary, we have elucidated the migration-associated transport of MIA protein to the cell rear and also disclosed a new mechanism by which KCa3.1 potassium channels promote cell migration.展开更多
To over come the drawbacks existing in current measurement methods for detecting and controlling colors in printing process, a new medal for color separation and dot recognition is proposed from a view of digital imag...To over come the drawbacks existing in current measurement methods for detecting and controlling colors in printing process, a new medal for color separation and dot recognition is proposed from a view of digital image processing and patter recognition. In this model, firstly data samples are collected from some color patches by the Fuzzy C-Means (FCM) method; then a classifier based on the Cerebellar Model Articulation Controller (CMAC) is constructed which is used to recognize color pattern of each pixel in a microscopic halftone image. The principle of color separation and the algorithm model are introduced and the experiments show the effectiveness of the CMAC-based classifier as opposed to the BP network.展开更多
The convenient and efficient procedure for one-pot preparation of quinaldine derivatives from multi component reaction of anilines, acetone and benzaldehyde without any solvent under microwave irradiation on the surfa...The convenient and efficient procedure for one-pot preparation of quinaldine derivatives from multi component reaction of anilines, acetone and benzaldehyde without any solvent under microwave irradiation on the surface of alumina impregnated with hydrochloric acid is developed.展开更多
The aim of this study was to rapidly isolate the major effective flavanoids from the extract of safflower(Carthamus tinctorius) using ODS medium pressure liquid chromatography(MPLC) and semi-preparative HPLC, guid...The aim of this study was to rapidly isolate the major effective flavanoids from the extract of safflower(Carthamus tinctorius) using ODS medium pressure liquid chromatography(MPLC) and semi-preparative HPLC, guided by a developed fingerprint. Twelve compounds were isolated and their structures were elucidated as kaempferol 3-O-β-D-rutinoside(1), kaempferol 3-O-β-D-glucoside(2), rutin(3), quercetin 3-O-β-D-glucoside(4), 6-hydroxykaempferol 3,6,7-tri-O-β-D-glucoside(5), 6-hydroxykaempferol 3-O-β-D-glucoside(6), 6-hydroxykaempferol 6,7-di-O-β-D-glucoside(7), 6-hydroxykaempferol 3-O-β-Drutinoside(8), 6-hydroxykaempferol 3,6-di-O-β-D-glucosyl 7-O-β-D-glucuronide(9), isosafflomin C(10), safflomin C(11) and hydroxysafflor yellow A(12) by spectroscopic analysis and comparing with the literature. Our results demonstrated that preparative pressurized liquid chromatography combined with HPLC fingerprint guide is an efficient tool to isolate the target compounds quickly.展开更多
In the present study, two new compounds from Ipomoea cairica were identified and demonstrated to have a-glucosidase inhibitory activity. They were isolated by column chromatography on silica gel and sephadex LH-20 and...In the present study, two new compounds from Ipomoea cairica were identified and demonstrated to have a-glucosidase inhibitory activity. They were isolated by column chromatography on silica gel and sephadex LH-20 and finally purified by prep-HPLC, with their structures being elucidated by spectroscopic methods, such as 1D- and 2D-NMR and HR-TOF-MS, and chemical methods. Compounds 1 and 2, named cairicoside A and cairicoside B, were evaluated for a-glucosidase inhibitory activity by the MTT method, with the ICs0 values being 25.3 ± 1.6 and 28.5± 3.3 μmol·L-1, respectively.展开更多
Orderly execution of two critical events during the cell cycle––DNA replication and chromosome segregation––ensures the stable transmission of genetic materials. The cohesin complex physically connects sister chro...Orderly execution of two critical events during the cell cycle––DNA replication and chromosome segregation––ensures the stable transmission of genetic materials. The cohesin complex physically connects sister chromatids during DNA replication in a process termed sister chromatid cohesion. Timely establishment and dissolution of sister chromatid cohesion is a prerequisite for accurate chromosome segregation, and is tight regulated by the cell cycle machinery and cohesin-associated proteins. In this review, we discuss recent progress in the molecular understanding of sister chromatid cohesion during the mitotic cell cycle.展开更多
基金The National Basic Research Program of China(No.2011CB707904)the National Natural Science Foundation of China(No.61201344,61271312,11301074)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK2012329)the Specialized Research Fund for the Doctoral Program of Higher Education(No.20110092110023,20120092120036)
文摘The optimized color space is searched by using the wavelet scattering network in the KTH_TIPS_COL color image database for image texture classification. The effect of choosing the color space on the classification accuracy is investigated by converting red green blue (RGB) color space to various other color spaces. The results show that the classification performance generally changes to a large degree when performing color texture classification in various color spaces, and the opponent RGB-based wavelet scattering network outperforms other color spaces-based wavelet scattering networks. Considering that color spaces can be changed into each other, therefore, when dealing with the problem of color texture classification, converting other color spaces to the opponent RGB color space is recommended before performing the wavelet scattering network.
文摘Segmental duplications on rice (Oryza sativa L.) chromosomes 8, 9, 11, and 12 were studied by examining the distributions of sequences resolved by 13 probes detecting multiple copies of DNA sequences. Four of the hybridization bands detected by a repetitive sequence probe, rTRS, were mapped to the ends of all the four chromosomes. Two or three of the bands detected by each of the other 12 probes were also mapped to different chromosomes. The bands detected by the same probe usually occurred in similar locations of different chromosomes. Loci detected by different DNA probes were often similarly arranged on different chromosomes. Chromosomes 8 and 9 showed colinearity of marker loci arrangement indicating a possible common origin. A segment on chromosome 9 was also very similar to the previously reported duplicated fragments on the ends of chromosomes 11 and 12 which were also detected in this study, indicating a likely common origin. Moreover, the various degrees of distributional similarity of the segments suggest a complex relationship among the chromosomes in the evolution of the rice genome. These results support the proposition that chromosome duplication and diversification may be a mechanism for the origin and evolution of the chromosomes in the rice genome.
基金The study was supported by Natural Science Foundation of Beijing to Wang Yuzhu (No. 6992013).
文摘In 2000 and 2001, 1-year-old seedlings of 7 economic tree species including chestnut, apricot, persimmon, peach, walnut, pear and apple were cultured in garden pots that had a diameter of 40 cm and were filled with clean sand. The major components of exudates released from their roots were isolated and analysed by GC-MS. Totally 200 kinds of organic chemicals were isolated, of which 3 kinds i.e. naphthalene, dimethylbenzene and dibutyl phthalate were principally controlled pollutants according to 'Blacklist of Principal Environment Pollutants in China' and the standard of U.S. Environmental Protection Agency (EPA). The research result provided theoretical evidence for selecting low-pollution economic forest crops in the water source protection area in Miyun Reservoir.
基金supported by the National High Technology Research and Development Program ofChina (863 Program) (2006AA09Z427)NSFC (Nos. 30800859 and 30871948)
文摘Polyphenols from the ethanol extracts of Sargassum tenerrimum (ST) with potent antiallergic effects were studied to optimize separation process through column chromatography. The adsorption and desorption characteristics of three widely used adsorbents: macroporous resin, silica gel, and polyvinylpolypyrrolidone (PVPP), were critically evaluated respectively and studied for the optimization of preparative separation of polyphenols. Static operations on these adsorbents showed that macroporous resin had the best adsorption and desorption capability among the three adsorbents. Dynamic adsorption and desorption with macroporous resin packed column were also conducted to optimize the parameters such as: with the optimal values shown in brackets, the concen- tration of extract solution (4 times diluted), pH value (6-7), adsorption speed (3BVh-1, bed volumes/per hour), concentration of ethanol (80%), elution speed (3 BV ht) and elution volume (7 BV). The chromatographic process so optimized gave a purity of 62.43% from the crude polyphenols, providing a promising basis for large scale preparation of bioactive polyphenols upon further scaling up tests.
基金funding support from the National Natural Science Foundation of China (No. 81804150 and No. 81703920)Project funded by China Postdoctoral Science Foundation (No. 2019M662790)+4 种基金Natural Science Foundation of Hunan Province, China (No. 2019JJ50442 and No. 2019JJ40226)Research-based Learning and Innovative Experiment Program Project for Hunan University Students (No. 2017280)Scientific Research Project of Hunan Traditional Chinese Medicine Administration (No. 201780)Open Fund Project of Hunan Provincial Key Laboratory for Prevention and Treatment of Ophthalmology and Otolaryngology Diseases with Chinese Medicine (No. 2018YZD05)Open Fund of the Domestic First-class Discipline Construction Project of Chinese Medicine of Hunan University of Chinese Medicine (No. 2018ZYX20 and No. 2018ZYX26)
文摘Objective To explore the molecular targets and associated potential pathways of Lycii Fructus(LF,Gou Qi Zi,枸杞子)in the treatment of retinitis pigmentosa(RP)by the approaches of network pharmacology and bioinformatics.Methods The potential blood-entry active ingredients and targets of LF were retrieved by Traditional Chinese Medicine Systems Pharmacology Database and Analysis Platform(TCMSP).RP-related gene targets were retrieved through disease comprehensive databases.Protein-protein interaction(PPI)network of LF component-targets and RP disease-targets was constructed by STRING,and the intersection of the 2 networks was extracted.Gene Ontology and Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway analysis of theintersection network were conducted by Database for Annotation,Visualization and Integrated Discovery(DAVID).CytoHubba was used to screen the key targets.Results A total of 188 chemical constituents related to LF was retrieved from TCMSP database.45 active ingredients were screened according to pharmacokinetic parameters oral bioavailability(OB)and drug similarity(DL).36 active ingredients were further screened and 201 targets related to these constituents were obtained.206 target genes directly related to RP were obtained from the disease comprehensive databases,and 89 genes were obtained from the intersection of componenttarget and disease-target PPI network.These genes were mainly involved in intracellular signal transduction,GTPase activity regulation,cell morphology regulation,and other biological processes.Molecular functions were mainly related to Rho guanine nucleotide exchange factor activity,GTPase activator activity,receptor signal protein serine/threonine kinase activity and so on.They were enriched in the cytoplasm,cell membrane,Golgi apparatus,and other regions.The mechanism was related to cell cycle pathways,neurotrophin signaling pathways,Ras signaling pathways,and so on.10 key gene targets of LF in the treatment of RP were screened.Conclusions The material basis for LF to exert its pharmacodynamic effect is 36 active ingredients such as cycloartenol,mandenol,and so on.The key targets of LF in the treatment of RP include 10 genes,such as Rho,PAK,and so on.The main mechanism is related to the regulation of the Ras signaling pathway,neurotrophin signaling pathway,cell cycle related pathway,and other signaling networks.
基金Supported by the National Natural Science Foundation of China(21476198,21576233)the International Science&Technology Cooperation Program of China(2015DFG42070)
文摘Five tryptophan analogues with a hydrophobic indole ring and an amino group on each molecule were used as functional ligands of mixed-mode resins for human serum albumin(HSA) purification. Their adsorption performance was evaluated and the effects of p H and salt addition on HSA adsorption were studied. The resins prepared showed typical p H-dependent adsorption and the highest adsorption capacity and affinity were found at pH 5.0for all the resins tested. The saturated adsorption capacity was 138.02 mg·g^(-1)with the tryptaminefunctionalized resin, which significantly decreased at p H below 4.0 due to electrostatic repulsion between ligands and HSA. Moreover, the addition of Na Cl or(NH_4)_2SO_4in media reduced HSA adsorption capacity, although the two salts showed different affecting profiles. The tryptamine-functionalized resin showed the best salt-tolerant performance, and its high adsorption capacity was maintained under high salt concentrations. In addition, the five resins prepared showed good adsorption selectivity for recombinant HSA from Pichia pastoris broth. Molecular docking results between tryptamine and HSA indicated that tryptamine was favorable to bind on Site II(indole-binding site) of HSA.
文摘Classical methyl-CpG binding proteins contain the conserved DNA binding motif methyl-cytosine binding domain(MBD), which preferentially binds to methylated CpG dinucleotides. These proteins serve as transcriptional repressors,mediating gene silencing via DNA cytosine methylation. Mutations in methyl-CpG binding protein 2 (MeCP2) have beenlinked to the human mental retardation disorder Rett syndrome, suggesting an important role for methyl-CpG bindingproteins in brain development and function. This mini-review summarizes the recent advances in studying the diversefunctions of MeCP2 as a prototype for other methyl-CpG binding proteins in the development and function of thevertebrate nervous system.
文摘Malignant melanoma, characterized by invasive local growth and early formation of metastases, is the most aggressive type of skin cancer. Melanoma inhibitory activity (MIA), secreted by malignant melanoma cells, interacts with the cell adhesion receptors, integrins a4131 and 05131, facilitating cell detachment and promoting formation of me- tastases. In the present study, we demonstrate that MIA secretion is confined to the rear end of migrating cells, while in non-migrating cells MIA accumulates in the actin cortex. MIA protein takes a conventional secretory pathway including coat protein complex I (COPI)- and coat protein complex II (COPII)-dependent protein transport to the cell periphery, where its final release depends on intracellular Ca2+ ions. Interestingly, the Ca2+-activated K+-channel, subfamily N, member 4 (KCa3.1), known to be active at the rear end of migrating cells, was found to support MIA secretion. Secretion was diminished by the specific KCa3.1 channel inhibitor TRAM-34 and by expression of dominant- negative mutants of the channel. In summary, we have elucidated the migration-associated transport of MIA protein to the cell rear and also disclosed a new mechanism by which KCa3.1 potassium channels promote cell migration.
文摘To over come the drawbacks existing in current measurement methods for detecting and controlling colors in printing process, a new medal for color separation and dot recognition is proposed from a view of digital image processing and patter recognition. In this model, firstly data samples are collected from some color patches by the Fuzzy C-Means (FCM) method; then a classifier based on the Cerebellar Model Articulation Controller (CMAC) is constructed which is used to recognize color pattern of each pixel in a microscopic halftone image. The principle of color separation and the algorithm model are introduced and the experiments show the effectiveness of the CMAC-based classifier as opposed to the BP network.
文摘The convenient and efficient procedure for one-pot preparation of quinaldine derivatives from multi component reaction of anilines, acetone and benzaldehyde without any solvent under microwave irradiation on the surface of alumina impregnated with hydrochloric acid is developed.
基金National Science Fund for Excellent Young Scholars(Grant No.81222051)National Key Technology R&D Program"New Drug Innovation"of China(Grant No.2012ZX09103201-036,2012ZX09301002-002-002 and 2012ZX09304-005)
文摘The aim of this study was to rapidly isolate the major effective flavanoids from the extract of safflower(Carthamus tinctorius) using ODS medium pressure liquid chromatography(MPLC) and semi-preparative HPLC, guided by a developed fingerprint. Twelve compounds were isolated and their structures were elucidated as kaempferol 3-O-β-D-rutinoside(1), kaempferol 3-O-β-D-glucoside(2), rutin(3), quercetin 3-O-β-D-glucoside(4), 6-hydroxykaempferol 3,6,7-tri-O-β-D-glucoside(5), 6-hydroxykaempferol 3-O-β-D-glucoside(6), 6-hydroxykaempferol 6,7-di-O-β-D-glucoside(7), 6-hydroxykaempferol 3-O-β-Drutinoside(8), 6-hydroxykaempferol 3,6-di-O-β-D-glucosyl 7-O-β-D-glucuronide(9), isosafflomin C(10), safflomin C(11) and hydroxysafflor yellow A(12) by spectroscopic analysis and comparing with the literature. Our results demonstrated that preparative pressurized liquid chromatography combined with HPLC fingerprint guide is an efficient tool to isolate the target compounds quickly.
基金supported by Chinese National Natural Science Fund(No.81202885)the Natural Science Foundation of Guangdong province of China(No.2015A030313585)
文摘In the present study, two new compounds from Ipomoea cairica were identified and demonstrated to have a-glucosidase inhibitory activity. They were isolated by column chromatography on silica gel and sephadex LH-20 and finally purified by prep-HPLC, with their structures being elucidated by spectroscopic methods, such as 1D- and 2D-NMR and HR-TOF-MS, and chemical methods. Compounds 1 and 2, named cairicoside A and cairicoside B, were evaluated for a-glucosidase inhibitory activity by the MTT method, with the ICs0 values being 25.3 ± 1.6 and 28.5± 3.3 μmol·L-1, respectively.
基金supported by the Welch Foundation(I-1441 to H.Y.)the Clayton Foundation,and Cancer Prevention and Research Institute of Texas(RP110465-P3 and RP120717-P2 to H.Y.)
文摘Orderly execution of two critical events during the cell cycle––DNA replication and chromosome segregation––ensures the stable transmission of genetic materials. The cohesin complex physically connects sister chromatids during DNA replication in a process termed sister chromatid cohesion. Timely establishment and dissolution of sister chromatid cohesion is a prerequisite for accurate chromosome segregation, and is tight regulated by the cell cycle machinery and cohesin-associated proteins. In this review, we discuss recent progress in the molecular understanding of sister chromatid cohesion during the mitotic cell cycle.