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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
31

Synthesis of internally linked carbazole DNA oligomers a potential monitor for charge transfer in DNA studies /

Umeweni, Chiko. January 2005 (has links)
Thesis (M. S.)--Chemistry and Biochemistry, Georgia Institute of Technology, 2006. / Fahrni, Christoph, Committee Member ; Collard, David, Committee Member ; Schuster, Gary, Committee Chair.
32

Estudo quÃmico e farmacolÃgico de Senna martiana (Benth) Irw. & Barn / Chemical and pharmacological of Senna martiana (Benth) Irw & Barn

EdÃngelo Moura Siqueira Macedo 04 February 2011 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Este trabalho apresenta o estudo da composiÃÃo quÃmica de Senna martiana (Benth) Irw. e Barn. pertencente à famÃlia da Leguminoseae. Norteou-se este estudo para o conhecimento dos constituintes quÃmicos fixos das flores e das raÃzes da planta. O levantamento bibliogrÃfico revelou a ausÃncia de estudos quÃmicos, biolÃgicos ou farmacolÃgicos realizados com esta espÃcie, motivo pelo qual a planta foi selecionada para estudo. O isolamento e purificaÃÃo dos constituintes quÃmicos foi realizado utilizando tÃcnicas como cromatografia por adsorÃÃo em coluna aberta (CC); cromatografia em camada delgada (CCD), cromatografia lÃquida de alta eficiÃncia (CLAE) e na determinaÃÃo das estruturas, tÃcnicas espectroscÃpicas tais como: absorÃÃo na regiÃo do infravermelho (IV); RessonÃncia MagnÃtica Nuclear de HidrogÃnio (RMN1H); RessonÃncia MagnÃtica Nuclear de Carbono 13 (RMN 13C) uni e bidimensionais. Na avaliaÃÃo do potencial farmacolÃgico da espÃcie, foram realizados ensaios de atividade antioxidante (mÃtodo DPPH e DHBA), atividade antitumoral (mÃtodo MTT) e atividade tripanocida de quatro compostos isolados frente a enzima GAPDH. O estudo quÃmico de Senna martiana (Benth) Irw. e Barn., permitiu o isolamento do Ãcido triacontanÃico (Ãc. melÃssico), -sitosterol e estigmasterol, e aâamirina, de trÃs antraquinonas 1,8-diidroxiladas, crisofanol, fisciona e aloe-emodina alÃm de trÃs heterosÃdeos antrÃnicos, dois deles inÃditos na literatura. / This work presents the study of the chemical composition of Senna martiana (Benth) Irw. and Barn. (Leguminosea). This survey was performed to the knowledge of the chemical constituents of the flowers and roots. The isolation and purification of chemical constituents of the plant was accomplished using cromatographic techniques and in the determination of the structures espectroscopic techniques (IR), Nuclear Magnetic Resonance of Hydrogen (RMN 1H); Nuclear Magnetic Resonance of Carbon 13 (RMN 13C). In evaluating the pharmacological potential of this species, were assayed for antioxidant activity (DPPH and DHBA), antitumor activity (MTT assay) and trypanocidal activity of four isolated compounds against the enzyme GAPDH. Chemical studies and of Senna martÃana (Benth) I&B, allowed to the isolation of triacontanoic acid, -sitosterol, stigmasterol, - amyrin, -amyrin, three 1.8-dihydroxyanthraquinones, chrysophanol, physcion and aloe-emodin, in addition to three glycosides anthrones, two of them previously unpublished in the literature.
33

Estudo QuÃmico de Plantas do Nordeste com atividade antioxidante: Senna martiana Benth (I. e B) / Chemical investigations of plant of northent and its antioxidant activity: Senna martiana Benth (I. e B)

EdÃngelo Moura Siqueira Macedo 22 February 2006 (has links)
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / Neste trabalho apresenta-se o estudo da composiÃÃo quÃmica de Senna martiana (Benth) Irw. e Barn. pertencente à famÃlia das Leguminosas (subfamÃlia Papilonoideae, sinÃnimo Fabaceae). Norteou-se este estudo para o conhecimento dos constituintes quÃmicos volÃteis das folhas e dos constituintes fixos das inflorescÃncias e do caule. Outro objeto de interesse foi a avaliaÃÃo da atividade antioxidante dos extratos hidroalcoÃlicos dos ÃrgÃos da planta acima citados. O levantamento bibliogrÃfico revelou a ausÃncia de estudos fitoquÃmicos, biolÃgicos ou farmacolÃgicos realizados com esta espÃcie, motivo pelo qual a planta foi selecionada para estudo. O estudo fitoquÃmico da planta foi realizado utilizando tÃcnicas como cromatografia por adsorÃÃo em coluna aberta (CC); cromatografia em camada delgada (CCD), e na determinaÃÃo das estruturas tÃcnicas espectroscÃpicas tais como: absorÃÃo na regiÃo do infravermelho (IV); RessonÃncia MagnÃtica Nuclear de HidrogÃnio (RMN 1H); RessonÃncia MagnÃtica Nuclear de Carbono 13 (RMN 13C) uni e bidimensionais. A extraÃÃo dos constituintes volÃteis foi realizada por hidrodestilaÃÃo usando-se forno de microondas como fonte de aquecimento e na avaliaÃÃo da atividade antioxidante utilizou-se como tÃcnicas de anÃlise, a capacidade seqÃestradora de radicais livres (mÃtodo DPPH) e a medida do potencial antioxidante (mÃtodo DHBA). O estudo do Ãleo fixo das sementes de Senna martiana, resultou na identificaÃÃo de quatorze Ãcidos graxos, sendo majoritÃrios, o Ãcido hexadecanÃico (37%) e o Ãcido 9,12-octadecanÃico (34,1%). O estudo cromatogrÃfico do extrato etanÃlico do caule de Senna martiana possibilitou o isolamento e identificaÃÃo do Ãcido triacontanÃico (Ãc. melÃssico), -sitosterol, de trÃs antraquinonas 1,8-dihidroxiladas, crisofanol, fisciona e aloe-emodina, cujas identidades quÃmicas foram confirmadas pela anÃlise de seus espectros e comparaÃÃo com os dados da literatura. Dentre os constituintes isolados obteve-se um heterosÃdeo de uma biantrona do crisofanol inÃdito na literatura. / This work presents the study of the chemical composition of Senna martiana (Benth) Irw. and Barn. belonging to the family of Leguminosas (subfamily Papilonoideae, synonym Fabaceae). this study was orientated for the volatile chemical representatives of the leaves knowledge and of the fixed representatives of the flowers and of the stem. Another object of interest was the evaluation of the antioxidant activity of the extracts hidroalcoÃlicos of the organs of the plant above mentioned. The bibliographical rising revealed the absence of studies phytochemistry, biological or pharmacolÃgics accomplished with this species, reason for which the plant was selected for study. The study phytochemistry of the plant was accomplished using techniques as cromatographic for adsorption in open column (CC); cromatographic in thin layer (CCD), and in the determination of the structures technical such espectroscopic as: absorption in the area of the red band (IV); Nuclear Magnetic Resonance of Hydrogen (RMN 1H); Nuclear Magnetic Resonance of Carbon 13 (RMN 13C) united and bidimensionais. The volatile representatives extraction was accomplished by hidrodestilacion being used microwave oven as heating source and in the evaluation of the antioxidant activity it was used as analysis techniques, the capacity kidnapper of free radicals (method DPPH) and the measure of the antioxidant potential (method DHBA). The study of the fixed oil of the seeds of Senna martiana, resulted in the identification of fourteen graxos acids, being majority, the hexadecanoic acid (37%) and the 9,12-octadecanoic acid (34,1%). The study cromatographic of the extract ethanolic of the stem of Senna martiana made possible the isolation and identification of the triacontanoic acid (melÃssico ac.), -sitosterol, of three anthraquinones 1,8-dihidroxylad, crysophanol, phyiscion and aloe-emodin, whose chemical identities were confirmed by the analysis of your spectra and comparison with the data of the literature. Among the isolated representatives it was obtained a heterosÃdeo of a bianthrone of the unpublished crysophanol in the literature.
34

Derivatives of 1,4-Naphthoquinone and 1,4-Anthraquinone

Aboytes, Peter 08 1900 (has links)
The purpose of this investigation was the synthesis of some 1,4-naphthoquinones and 1,4-anthraquinones. It will be shown that some of these substituted quinones exhibit physiological properties.
35

Genetic studies on pleiotropic polyoxin resistant mutants of Bipolaris maydis / トウモロコシごま葉枯病菌の多面的なポリオキシン耐性株の遺伝学的研究

Chen, Daidi 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第21158号 / 農博第2284号 / 新制||農||1060(附属図書館) / 学位論文||H30||N5132(農学部図書室) / 京都大学大学院農学研究科地域環境科学専攻 / (主査)教授 田中 千尋, 教授 本田 与一, 教授 宮川 恒 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DGAM
36

Genetic transformation of Ceratotheca triloba for the production of anthraquinones from hairy root cultures

Naicker, Leeann January 2012 (has links)
Submitted in complete fulfillment for the Degree of Master of Technology: Biotechnology, Durban University of Technology, 2012. / Many secondary metabolites that have been extracted from medicinal plants have been used as source of clinical drugs. However, the concentration of the active metabolites in plants is generally low. An attractive alternative for producing these important secondary metabolites is via plant tissue culture technology. More particularly, the genetic transformation of a plant tissue by Agrobaterium rhizogenes has been employed for producing high yields of secondary metabolites. In a previous study, three structurally similar anthraquinones: 9,10-Anthracenedione, 1-Hydroxy-4-methylanthraquinone and 5,8-Dimethoxy-2,3,10,10a-tetrahydro-1H,4aH-phenanthrene-4,9-dione, and one steroid; Androst-5-ene-3, 17, 19-triol were isolated from the root extracts of C. triloba. The anthraquinones have shown to exhibit the anticancer mechanism which involves the inhibition of the activity of the human topoisomerase II enzyme that transforms supercoiled DNA to linear DNA. However, these anthraquinones were found in very low concentrations. Therefore, in this study we used plant cell and tissue culture systems (cell suspension, shoot and hairy root cultures) of C. triloba to increase the production of anthraquinones. Since the establishment of C. triloba in vitro plant systems required a source sterile explants, a protocol that involved the use of NaCIO was optimized for the sterilization and subsequent germination of C. triloba seeds which were micro-propagated into shoot cultures. These cultures provided a source explants for the induction of callus and hairy root cultures. The biomass of these plant cell and tissue cultures were subsequently bulked up for the extraction for anthraquinones and the yields were compared followed by fractionation and identification of the major compounds. The bioactivity of the fractions was evaluated by testing their cytotoxicity on cancer cells and anti-topoisomerase activity. The sterilization protocol that provided sterile seeds was found to be a solution of 30% NaCIO at an exposure time of 10 minutes. From the sterilized seeds shoot cultures were established on MS medium. The leaf explants of the shoot cultures were then used to induce callus cultures which subsequently were transferred to liquid medium whereby the total biomass of suspension cultures increased from 4 g to 134.18 g (wet weight). Also hairy roots cultures were established from stem explants with a low cell density inoculum of A. rhizogenes at a transformation efficiency of 73%. The growth of these hairy roots was slow in hormone free medium. This was overcomed with the use NAA and IAA which increased the xvii biomass from 1.03 g in the control culture (without hormone) to 23.91 g and 46.13 g respectively. An evaluation of the anthraquinones in the field root and hairy root, cell suspension and shoot culture extracts was carried out by using their Thin Layer Chromatography profiles and the High Performance Liquid Chromatography profiles as well as the standards, 9,10-Anthracenedione and 1-Hydroxy-4-methylanthaquinone. TLC analysis showed that the RF values of the fractions CT01 and CT02 matched the RF values of anthraquinones standards while HPLC analysis revealed that hairy root cultures supplemented with IAA (125.03 μg.mg-1) or NAA (98.25 μg. mg-1) produced a higher concentration of anthraquinones than the control culture (without hormone) (13.33 μg.mg-1), the field roots (33.51 μg. mg-1) and the shoot (3.23 μg.mg-1) and cell suspension cultures (13.17 μg.mg-1). Due to co-elution of the compounds in HPLC analysis, six fractions were isolated by Preparative Thin Layer Chromatography from the hairy root extract (obtained from the culture supplemented with NAA) and were coded as CT01, CT02, CT03, CT04, CT05 and CT06. The compounds in these fractions were identified by Electron Ionization-Liquid chromatography-Mass Spectroscopy and it was found that the hairy roots produced one acridone derivative; 5-Methoxy-2-nitro-10H-acridin-9-one, one naphthoquinone derivative; 2H-Naphto[2,3-b]pyran-5,10-dione,3,4-dihydro-2,2-dimethyl- and seven anthracenedione derivatives. These were: i) 5,8-Dimethoxy-2,3,10,10a-tetrahydro-1H,4aH-phenanthrene-4,9-dione, ii) 9,10-Anthracenedione, 2-methyl-, iii) 1-Hydroxy-4-methylanthraquinone, iv) 9,10-Anthracenedione, 2-ethyl-, v) 1,5-Diaminoanthraquinone, vi) Phenanthrene, 3,6-dimethoxy-9-methyl-, vii) 9,10-Anthracenedione, 1,4-dimethyl-. Fractions CT01 (5,8-Dimethoxy-2,3,10,10a-tetrahydro-1H,4aH-phenanthrene-4,9-dione, 9,10-Anthracenedione, 2-methyl- and 1-Hydroxy-4-methylanthraquinone) and CT02 (9,10- Anthracenedione, 2-ethyl-) were cytotoxic to the DU-145 cancer cell line at concentrations of 125 μg.mg-1 to 1000 μg.mg-1. These fractions also showed anti-topoisomerase activity as they inhibited the conversion of supercoiled DNA into linear DNA. In conclusion this is the first study that describes the transformation of C. triloba by A. rhizogenes mediated transformation and compares the production of anthraquinones in C. triloba hairy roots to the field roots, shoot and cell suspension cultures. This study has xviii indicated that hairy root cultures is a high-yielding production system for anthraquinones (5,8-Dimethoxy-2,3,10,10a-tetrahydro-1H,4aH-phenanthrene-4,9-dione, 1-Hydroxy-4-methylanthraquinone, 9,10-Anthracenedione, 2-methyl- and 9,10- Anthracenedione, 2-ethyl-) which could have the potential to be used in cancer therapy. In addition the discovery of C. triloba hairy roots having the biosynthetic capacity to synthesize five valuable anthraquinone derivatives that are not found the field roots has also been revealed. / National Research Foundation.
37

Résistance bactérienne et phytomolécules antimicrobiennes issues de Morinda morindoides

Moroh, Jean-luc Aboya 25 September 2013 (has links) (PDF)
Nous assistons durant ces trente dernières années à une croissance de la fréquence d'apparition des bactéries résistantes aux antibiotiques. Face à la récurrence des infections difficiles à traiter dues à ces bactéries pathogènes multi-résistantes, le renforcement de l'arsenal des antimicrobiens fait partir des préoccupations majeures de santé publique. À ce titre, une approche ethno-pharmacologique a été initiée dans le cadre d'une coopération entre le laboratoire de pharmacodynamie biochimique (Université Félix Houphouët-Boigny, Côte d'Ivoire) et le laboratoire universitaire de biodiversité et d'écologie microbienne(Université de Bretagne Occidentale, France). Dans cette approche, les habitudes traditionnelles d'automédication par les plantes médicinales ont été exploitées pour identifier de nouvelles sources de composés antimicrobiens. Dans une première partie de cette présente étude, une investigation sur les résistances bactériennes en Côte d'Ivoire a montré non seulement une évolution de la fréquence d'apparition des bactéries résistantes aux antibiotiques dans le temps, mais aussi une évolution de ces souches résistantes vers des différents types de multi-résistances. Dans la seconde partie, Morinda morindoides, une plante médicinale ivoirienne, a suscité notre attention pour la recherche de substances antimicrobiennes. À partir de 18 extraits des différents organes de cette plante, des tests d'activité antimicrobienne ont permis de justifier son utilisation en médecine traditionnelle. L'extrait à l'acétonitrile de la racine qui affiche l'activité la plus intéressante a servi pour isoler et caractériser 12 phytomolécules antimicrobiennes dont une se distingue par sa structure chimique originale, la morindoïdine. En plus de leurs paramètres antimicrobiens, d'autres propriétés biologiques de ces substances ont été évaluées telles que, leur pouvoir antioxydant, leur cytotoxicité, leur activité hémolytique et leur cible moléculaire. Cette évaluation a révélé un mode d'action sans doute proche de celui des quinolones.
38

Estudo de fungos endofíticos associados a plantas da família Asteraceae como fontes de metabólitos secundários e em processos de biotransformações / Studies of endophytic fungi found in association with species of Asteraceae as sources of secondary metabolites and on biotransformation processes.

Borges, Warley de Souza 04 July 2008 (has links)
Fungos endofíticos constituem uma fonte promissora e ainda pouco explorada de novas substâncias potencialmente bioativas, que podem ter aplicações na medicina, agricultura e biologia química. Neste trabalho foram isolados cinco fungos endofíticos das folhas de Tithonia diversifolia, os quais foram cultivados em pequena escala e avaliados em diversos bioensaios. O fungo endofítico Phoma sorghina foi cultivado em escala ampliada, produzindo nove substâncias, sendo três derivados antraquinônicos inéditos na literatura. Três fungos endofíticos associados à Viguiera robusta foram estudados. De Colletotrichum gloeosporioides foram isoladas oito substâncias, sendo um derivado dicetopiperazínico e um derivado aminoaçúcar inéditos na literatura. Diaporthe phaesolorum produziu três derivados dicetopiperazinicos, um inédito na literatura. Chaetomium globosum produziu treze substâncias, sendo oito derivados azaphilônicos inéditos. Algumas linhagens endofíticas foram avaliadas em experimentos de biotransformação de três naftoquinonas e da 1-tetralona, catalisando reações de oxidação e redução. O fungo Diaphorte phaseolorum catalisou uma reação de metilação inédita na literatura de biotransformação. / Endophytic fungi are a promising and untapped source of potential biologically active compounds that might be useful as therapeutic and agrochemical agents, or chemical biology tools. In this thesis five endophytic fungi were isolated from the leaves Tithonia diversifolia. All the strains have been cultivated in small scale and the extracts submitted to bioassays. The culture of the endophyte Phoma sorghina was scaled up, affording six known compounds and three novel anthraquinone derivatives. Three endophytes from Viguiera robusta have also been studied as sources of natural products. Colletotrichum gloeosporioides produced six known compounds, one novel aminosugar and one new diketopiperazine derivative. Diaporthe phaesolorum biosynthesized three diketopiperazine derivatives, one novel in the literature. Five known compounds and eight novel azaphilone derivatives were isolated from Chaetomium globosum. Some endophytic strains have been evaluated in biotransformation experiments of three naphthoquinones and 1-tetralone, catalyzing oxidation and reduction reactions. The endophyte Diaphorte phaseolorum catalyzed a novel methylation reaction in the biotransformation literature.
39

Zero-Valent Iron Decolorization of the Anthraquinone Dye Reactive Blue 4 and Biodegradation Assessment of its Decolorization Products

Yang, Hanbae 18 April 2005 (has links)
Anthraquinone dyes constitute the second largest class of textile dyes, and are used extensively in the textile industry. A high fraction of the initial reactive dye mass used in the dyeing process remains in the spent dyebath. Reactive dyes are not readily removed by typical wastewater treatment processes and the high salt concentration typical of reactive dyeing further complicates the management of spent reactive dyebaths. Investigation of the reductive transformation of reactive anthraquinone dyes and their decolorization products has been very limited. Additionally, very limited research has been conducted on the decolorization of spent reactive dyebaths. Research was conducted to investigate the key operational parameters of batch and continuous-flow ZVI decolorization of a reactive anthraquinone dye, Reactive Blue 4 (RB4), under anoxic conditions, as well as the potential for the biodegradation of its decolorization products in a halophilic culture under aerobic conditions. The effect of two operational parameters, such as mixing intensity and initial dye concentration, on the ZVI batch decolorization kinetics indicates that ZVI decolorization of RB4 is a surface-catalyzed, mass transfer-limited process. The high salt and base concentrations enhanced the rate of RB4 decolorization. Based on parameters such as porosity, hydraulic conductivity, pore water velocity, and dispersion coefficient, non-ideal transport characteristics were observed in a continuous-flow ZVI column. The results of a long-term continuous-flow ZVI decolorization kinetics demonstrated that continuous-flow ZVI decolorization is feasible. However, column porosity losses and a shift of reaction kinetics occur in long-term column operation. ZVI decolorization of RB4 was successfully described with a pseudo first-order or a site saturation model. Lastly, the RB4 decolorization products generated by ZVI treatment had no inhibitory effect on the halophilic culture. However, biodegradation and/or mineralization of RB4 decolorization products was not observed after a long-term incubation of the culture. This research demonstrated the feasibility of ZVI decolorization of reactive anthraquinone dyes, which will help in the development of a continuous-flow, dyebath decolorization process and the possible reuse of the renovated dyebath in the dyeing operation. Such a system could lead to substantial reduction of water usage, as well as a decrease of salt and dye discharges.
40

Spin selective reactivity of arylcations ; Part II: Anthraquinone oligonucleotide conjugates as probes of electron transfer in DNA

Gasper, Susan M. 05 1900 (has links)
No description available.

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