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Pesquisa : B01.650.940.800.575.912.250.100.895 [Categoria DeCS]
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PMID:29218491
Autor:Prexler SM; Singh R; Moerschbacher BM; Dirks-Hofmeister ME
Endereço:Institute for Biology and Biotechnology of Plants, University of Münster, Schlossplatz 8, 48143, Münster, Germany.
Título:A specific amino acid residue in the catalytic site of dandelion polyphenol oxidases acts as 'selector' for substrate specificity.
Fonte:Plant Mol Biol; 96(1-2):151-164, 2018 Jan.
ISSN:1573-5028
País de publicação:Netherlands
Idioma:eng
Resumo:KEY MESSAGE: Successful site-directed mutagenesis combined with in silico modeling and docking studies for the first time offers experimental proof of the role of the 'substrate selector' residue in plant polyphenol oxidases. The plant and fungi enzymes responsible for tissue browning are called polyphenol oxidases (PPOs). In plants, PPOs often occur as families of isoenzymes which are differentially expressed, but little is known about their physiological roles or natural substrates. In a recent study that explored these structure-function relationships, the eleven known dandelion (Taraxacum officinale) PPOs were shown to separate into two different phylogenetic groups differing in catalytic cavity architecture, kinetic parameters, and substrate range. The same study proposed that the PPOs' substrate specificity is controlled by one specific amino acid residue positioned at the entrance to the catalytic site: whereas group 1 dandelion PPOs possess a hydrophobic isoleucine (I) at position H +1, group 2 PPOs exhibit a larger, positively charged arginine (R). However, this suggestion was only based on bioinformatic analyses, not experiments. To experimentally investigate this hypothesis, we converted group 1 ToPPO-2 and group 2 ToPPO-6 into PPO-2-I R and PPO-6-R I, respectively, and expressed them in E. coli. By performing detailed kinetic characterization and in silico docking studies, we found that replacing this single amino acid significantly changed the PPO's substrate specificity. Our findings therefore proof the role of the 'substrate selector' in plant PPOs.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:EC 1.10.3.1 (Catechol Oxidase)


  2 / 272 MEDLINE  
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PMID:29187173
Autor:Jeon D; Kim SJ; Kim HS
Endereço:Department of Molecular Medicine, College of Medicine, Inha University, Incheon, 22212, Republic of Korea.
Título:Anti-inflammatory evaluation of the methanolic extract of Taraxacum officinale in LPS-stimulated human umbilical vein endothelial cells.
Fonte:BMC Complement Altern Med; 17(1):508, 2017 Nov 29.
ISSN:1472-6882
País de publicação:England
Idioma:eng
Resumo:BACKGROUND: Atherosclerosis is a chronic vascular inflammatory disease. Since even low-level endotoxemia constitutes a powerful and independent risk factor for the development of atherosclerosis, it is important to find therapies directed against the vascular effects of endotoxin to prevent atherosclerosis. Taraxacum officinale (TO) is used for medicinal purposes because of its choleretic, diuretic, antioxidative, anti-inflammatory, and anti-carcinogenic properties, but its anti-inflammatory effect on endothelial cells has not been established. METHODS: We evaluated the anti-inflammatory activity of TO filtered methanol extracts in LPS-stimulated human umbilical vein endothelial cells (HUVECs) by monocyte adhesion and western blot assays. HUVECs were pretreated with 100 µg/ml TO for 1 h and then incubated with 1 µg/ml LPS for 24 h. The mRNA and protein expression levels of the targets (pro-inflammatory cytokines and adhesion molecules) were analyzed by real-time PCR and western blot assays. We also preformed HPLC analysis to identify the components of the TO methanol extract. RESULTS: The TO filtered methanol extracts dramatically inhibited LPS-induced endothelial cell-monocyte interactions by reducing vascular cell adhesion molecule-1 and monocyte chemoattractant protein-1, and pro-inflammatory cytokine expression. TO suppressed the LPS-induced nuclear translocation of NF-κB, whereas it did not affect MAPK activation. CONCLUSIONS: Our findings demonstrated that methanol extracts of TO could attenuate LPS-induced endothelial cell activation by inhibiting the NF-κB pathway. These results indicate the potential clinical benefits and applications of TO for the prevention of vascular inflammation and atherosclerosis.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Anti-Inflammatory Agents); 0 (Lipopolysaccharides); 0 (NF-kappa B); 0 (Plant Extracts); Y4S76JWI15 (Methanol)


  3 / 272 MEDLINE  
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PMID:28570890
Autor:Nadgórska-Socha A; Kandziora-Ciupa M; Trzesicki M; Barczyk G
Endereço:University of Silesia, Department of Ecology, Bankowa 9, PL 40-007, Katowice, Poland. Electronic address: aleksandra.nadgorska-socha@us.edu.pl.
Título:Air pollution tolerance index and heavy metal bioaccumulation in selected plant species from urban biotopes.
Fonte:Chemosphere; 183:471-482, 2017 Sep.
ISSN:1879-1298
País de publicação:England
Idioma:eng
Resumo:This research was carried out on plants Taraxacum officinale, Plantago lanceolata, Betula pendula and Robinia pseudoacacia growing in urban biotopes with different levels of heavy metal contamination in the city of Dabrowa Górnicza (southern Poland). Based on the pollution index, the highest heavy metal contamination was determined in the site 4 (connected with industry emitters) and 6 (high traffic). The metal accumulation index (MAI) values ranged within the biotopes in Dabrowa Górnicza between 7.3 and 20.6 for R. pseudoacacia, 4.71-23.1 for P. lanceolata, 4.68-28.1 for T. officinale and 10.5-27.2 for B. pendula. Increasing tendency in proline content in biotopes connected with high traffic was found in the leaves of investigated plants (except R. pseudoacacia). Similar tendency was observed for ascorbic acid content in the foliage of the plants as well as in T. officinalle in stands connected industrial emission. Non-protein thiols content increased especially in the leaves of R. pseudoacacia in biotopes with high traffic emissions as well as in T. officinale in stands connected with industry. The mean values of APTI (Air Pollution Tolerance Index) within the city of Dabrowa Górnicza for investigated plants were found in the following ascending order P. lanceolata < R. pseudoacacia < B. pendula < T. officinale. Among the investigated plants B. pendula and T. officinale may be postulated as appropriate plants in urban areas with considerable soil and air contamination, especially with heavy metals. The results indicate that species deemed tolerant according to APTI are suitable plants in barriers areas to combat atmospheric pollution.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Air Pollutants); 0 (Metals, Heavy); 0 (Soil Pollutants); PQ6CK8PD0R (Ascorbic Acid)


  4 / 272 MEDLINE  
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PMID:28480383
Autor:Wang Y; Li GH; Liu XY; Xu L; Wang SS; Zhang XM
Endereço:Agricultural College of Yanbian University, China.
Título: ANTI-INFLAMMATORY EFFECTS OF TARAXASTEROL AGAINST ANIMAL MODELS.
Fonte:Afr J Tradit Complement Altern Med; 14(1):43-51, 2017.
ISSN:2505-0044
País de publicação:Nigeria
Idioma:eng
Resumo:BACKGROUND: Traditional Chinese medicine has been widely used to treat various inflammatory diseases. Taraxasterol is one of the main active components isolated from . Recently, we have demonstrated that taraxasterol has the anti-inflammatory effects. This study aims to determine the in vivo anti-inflammatory effects of taraxasterol against animal models. MATERIALS AND METHODS: Anti-inflammatory effects were assessed in four animal models by using dimethylbenzene-induced mouse ear edema, carrageenan-induced rat paw edema, acetic acid-induced mouse vascular permeability and cotton pellet-induced rat granuloma tests. RESULTS: Our results demonstrated that taraxasterol dose-dependently attenuated dimethylbenzene-induced mouse ear edema and carrageenan-induced rat paw edema, decreased acetic acid-induced mouse vascular permeability and inhibited cotton pellet-induced rat granuloma formation. CONCLUSION: Our finding indicates that taraxasterol has obvious in vivo anti-inflammatory effects against animal models. It will provide experimental evidences for the traditional use of and taraxasterol in inflammatory diseases.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Anti-Inflammatory Agents); 0 (Drugs, Chinese Herbal); 0 (Sterols); 0 (Triterpenes); 64SK2ERN9P (taraxasterol)


  5 / 272 MEDLINE  
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PMID:28364786
Autor:Gargouri M; Magné C; Ben Amara I; Ben Saad H; El Feki A
Endereço:Laboratory of Animal Ecophysiology, Faculty of Sciences, University of Sfax, 3038 Sfax, Tunisia.
Título:Dandelion-enriched diet of mothers alleviates lead-induced damages in liver of newborn rats.
Fonte:Cell Mol Biol (Noisy-le-grand); 63(2):67-75, 2017 Feb 28.
ISSN:1165-158X
País de publicação:France
Idioma:eng
Resumo:Lead (Pb) is a highly toxic metal present in the environment. It causes disturbances of several functions, including hematologic, renal, reproductive and nervous ones. Preventive or curative use of medicinal plants against these disorders may be a promising and safe therapeutic strategy. This study evaluated the hepatic toxic effects of prenatal exposure to lead in rats and the possible protective effect of dandelion (Taraxacum officinale) added to the diet. Female rats were given a normal diet (control) or a diet enriched with dandelion (treated). In addition, lead acetate was administered to half of the rats through drinking water from the 5th day of gestation until the 14th day postpartum. Lead toxicity was evaluated in their offspring by measuring body and liver weights, plasma biochemical parameters, liver damage, as well as protein content and activities of antioxidant enzymes in the liver tissues. Lead poisoning of mothers caused lead deposition in blood and stomach of their pups as well as hepatic tissue damages. Moreover, significant decreases in liver weight and protein content were found. Lead treatment caused oxidative stress and marked changes in the activity of antioxidant enzymes. However, no damages or biochemical changes were observed in puppies from the rats co-treated with lead and dandelion. These results indicate that supplementation of pregnant and lactating rats with dandelion protects their offspring against lead poisoning, likely through reduction of oxidative stress and liver damages.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Plant Extracts); 0 (Protective Agents); 2P299V784P (Lead); EC 1.11.1.6 (Catalase); EC 1.15.1.1 (Superoxide Dismutase)


  6 / 272 MEDLINE  
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PMID:28303526
Autor:Bont Z; Arce C; Huber M; Huang W; Mestrot A; Sturrock CJ; Erb M
Endereço:Institute of Plant Sciences, University of Bern, Bern, Switzerland.
Título:A Herbivore Tag-and-Trace System Reveals Contact- and Density-Dependent Repellence of a Root Toxin.
Fonte:J Chem Ecol; 43(3):295-306, 2017 Mar.
ISSN:1573-1561
País de publicação:United States
Idioma:eng
Resumo:Foraging behavior of root feeding organisms strongly affects plant-environment-interactions and ecosystem processes. However, the impact of plant chemistry on root herbivore movement in the soil is poorly understood. Here, we apply a simple technique to trace the movement of soil-dwelling insects in their habitats without disturbing or restricting their interactions with host plants. We tagged the root feeding larvae of Melolontha melolontha with a copper ring and repeatedly located their position in relation to their preferred host plant, Taraxacum officinale, using a commercial metal detector. This method was validated and used to study the influence of the sesquiterpene lactone taraxinic acid ß-D-glucopyranosyl ester (TA-G) on the foraging of M. melolontha. TA-G is stored in the latex of T. officinale and protects the roots from herbivory. Using behavioral arenas with TA-G deficient and control plants, we tested the impact of physical root access and plant distance on the effect of TA-G on M. melolontha. The larvae preferred TA-G deficient plants to control plants, but only when physical root contact was possible and the plants were separated by 5 cm. Melolontha melolontha showed no preference for TA-G deficient plants when the plants were grown 15 cm apart, which may indicate a trade-off between the cost of movement and the benefit of consuming less toxic food. We demonstrate that M. melolontha integrates host plant quality and distance into its foraging patterns and suggest that plant chemistry affects root herbivore behavior in a plant-density dependent manner.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Latex); 0 (Plant Proteins); 0 (Soil); 0 (Toxins, Biological)


  7 / 272 MEDLINE  
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PMID:28260050
Autor:Yoon CS; Ko W; Lee DS; Kim DC; Kim J; Choi M; Beom JS; An RB; Oh H; Kim YC
Endereço:College of Pharmacy, Wonkwang University, Iksan, Jeonbuk 54538, Republic of Korea.
Título:Taraxacum coreanum protects against glutamate-induced neurotoxicity through heme oxygenase-1 expression in mouse hippocampal HT22 cells.
Fonte:Mol Med Rep; 15(4):2347-2352, 2017 Apr.
ISSN:1791-3004
País de publicação:Greece
Idioma:eng
Resumo:Taraxacum coreanum Nakai is a dandelion that is native to Korea, and is widely used as an edible and medicinal herb. The present study revealed the neuroprotective effect of this plant against glutamate-induced oxidative stress in HT22 murine hippocampal neuronal cells. Ethanolic extracts from the aerial (TCAE) and the root parts (TCRE) of T. coreanum were prepared. Both extracts were demonstrated, by high performance liquid chromatography, to contain caffeic acid and ferulic acid as representative constituents. TCAE and TCRE significantly increased cell viability against glutamate-induced oxidative stress in mouse hippocampal HT22 cells. Western blot analysis revealed that treatment of HT22 cells with the extracts induced increased expression of the enzyme heme oxygenase-1 (HO-1), compared with untreated cells, in a concentration-dependent manner. Increased HO-1 enzymatic activity, compared with untreated cells, was also demonstrated following treatment with TCAE and TCRE. In addition, western blot analysis of the nuclear fractions of both TCAE and TCRE-treated HT22 cells revealed increased levels of nuclear factor erythroid 2 like 2 (Nrf2) compared with untreated cells, and decreased Nrf2 levels in the cytoplasmic fraction compared with untreated cells. The present study suggested that the neuroprotective effect of T. coreanum is associated with induction of HO-1 expression and Nrf2 translocation to the nucleus. Therefore, T. coreanum exhibits a promising function in prevention of neurodegeneration. Further studies will be required for the isolation and the full characterization of its active substances.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (Neuroprotective Agents); 0 (Plant Extracts); 3KX376GY7L (Glutamic Acid); EC 1.14.14.18 (Heme Oxygenase-1)


  8 / 272 MEDLINE  
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PMID:28220565
Autor:Kaur S; Vasar M
Endereço:Clinic of Dermatology, Tartu University, 50417 Tartu, Estonia.
Título:Contact allergy to the ingredients of moisturizers in a boy with atopic dermatitis.
Fonte:Contact Dermatitis; 76(3):180-181, 2017 Mar.
ISSN:1600-0536
País de publicação:England
Idioma:eng
Tipo de publicação: CASE REPORTS; JOURNAL ARTICLE
Nome de substância:0 (Cosmetics); 0 (Plant Extracts)


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PMID:28182646
Autor:M Salih RH; Majeský L; Schwarzacher T; Gornall R; Heslop-Harrison P
Endereço:Department of Genetics, University of Leicester, Leicester, United Kingdom.
Título:Complete chloroplast genomes from apomictic Taraxacum (Asteraceae): Identity and variation between three microspecies.
Fonte:PLoS One; 12(2):e0168008, 2017.
ISSN:1932-6203
País de publicação:United States
Idioma:eng
Resumo:Chloroplast DNA sequences show substantial variation between higher plant species, and less variation within species, so are typically excellent markers to investigate evolutionary, population and genetic relationships and phylogenies. We sequenced the plastomes of Taraxacum obtusifrons Markl. (O978); T. stridulum Trávnicek ined. (S3); and T. amplum Markl. (A978), three apomictic triploid (2n = 3x = 24) dandelions from the T. officinale agg. We aimed to characterize the variation in plastomes, define relationships and correlations with the apomictic microspecies status, and refine placement of the microspecies in the evolutionary or phylogenetic context of the Asteraceae. The chloroplast genomes of accessions O978 and S3 were identical and 151,322 bp long (where the nuclear genes are known to show variation), while A978 was 151,349 bp long. All three genomes contained 135 unique genes, with an additional copy of the trnF-GGA gene in the LSC region and 20 duplicated genes in the IR region, along with short repeats, the typical major Inverted Repeats (IR1 and IR2, 24,431bp long), and Large and Small Single Copy regions (LSC 83,889bp and SSC 18,571bp in O978). Between the two Taraxacum plastomes types, we identified 28 SNPs. The distribution of polymorphisms suggests some parts of the Taraxacum plastome are evolving at a slower rate. There was a hemi-nested inversion in the LSC region that is common to Asteraceae, and an SSC inversion from ndhF to rps15 found only in some Asteraceae lineages. A comparative repeat analysis showed variation between Taraxacum and the phylogenetically close genus Lactuca, with many more direct repeats of 40bp or more in Lactuca (1% larger plastome than Taraxacum). When individual genes and non-coding regions were for Asteraceae phylogeny reconstruction, not all showed the same evolutionary scenario suggesting care is needed for interpretation of relationships if a limited number of markers are used. Studying genotypic diversity in plastomes is important to characterize the nature of evolutionary processes in nuclear and cytoplasmic genomes with the different selection pressures, population structures and breeding systems.
Tipo de publicação: JOURNAL ARTICLE


  10 / 272 MEDLINE  
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PMID:28152978
Autor:Zhang Y; Iaffaldano BJ; Zhuang X; Cardina J; Cornish K
Endereço:Department of Horticulture and Crop Science, The Ohio State University, Ohio Agricultural Research and Development Center, 1680 Madison Avenue, Wooster, OH, 44691, USA.
Título:Chloroplast genome resources and molecular markers differentiate rubber dandelion species from weedy relatives.
Fonte:BMC Plant Biol; 17(1):34, 2017 Feb 02.
ISSN:1471-2229
País de publicação:England
Idioma:eng
Resumo:BACKGROUND: Rubber dandelion (Taraxacum kok-saghyz, TK) is being developed as a domestic source of natural rubber to meet increasing global demand. However, the domestication of TK is complicated by its colocation with two weedy dandelion species, Taraxacum brevicorniculatum (TB) and the common dandelion (Taraxacum officinale, TO). TB is often present as a seed contaminant within TK accessions, while TO is a pandemic weed, which may have the potential to hybridize with TK. To discriminate these species at the molecular level, and facilitate gene flow studies between the potential rubber crop, TK, and its weedy relatives, we generated genomic and marker resources for these three dandelion species. RESULTS: Complete chloroplast genome sequences of TK (151,338 bp), TO (151,299 bp), and TB (151,282 bp) were obtained using the Illumina GAII and MiSeq platforms. Chloroplast sequences were analyzed and annotated for all the three species. Phylogenetic analysis within Asteraceae showed that TK has a closer genetic distance to TB than to TO and Taraxacum species were most closely related to lettuce (Lactuca sativa). By sequencing multiple genotypes for each species and testing variants using gel-based methods, four chloroplast Single Nucleotide Polymorphism (SNP) variants were found to be fixed between TK and TO in large populations, and between TB and TO. Additionally, Expressed Sequence Tag (EST) resources developed for TO and TK permitted the identification of five nuclear species-specific SNP markers. CONCLUSIONS: The availability of chloroplast genomes of these three dandelion species, as well as chloroplast and nuclear molecular markers, will provide a powerful genetic resource for germplasm differentiation and purification, and the study of potential gene flow among Taraxacum species.
Tipo de publicação: JOURNAL ARTICLE
Nome de substância:0 (DNA, Plant); 0 (Genetic Markers)



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