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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.
161

MicroRNA Signature in the Chemoprevention of Breast Cancer Stem Cells by Active Hexose Correlated Compound (AHCC)

Graham, Emilie A. January 2016 (has links)
Complementary and Alternative Medicine (CAM) is popularly used among breast cancer patients to improve their quality of life. CAM includes dietary supplements such as Active Hexose Correlated Compound (AHCC®), a cultured mushroom extract shown to positively influence the immune system and cancer. Breast cancer recurrence is believed to be caused by cancer stem cells (CSCs). We postulated that AHCC impacts CSCs epigenetically by targeting miRNA pathways. The effects of AHCC on mammosphere growth were observed in MDA-MB-231, MCF-7, and 4T1 cells. Profiling, RT2-qPCR, and western blot analyses were performed to determine AHCC influence on miRNAs and Tenascin C protein in TNBC cell line MDA-MB-231. Balb/c mice were gavaged with AHCC to examine tumorigenesis effects. Our results demonstrated that AHCC reduced mammosphere growth and cell migration, and upregulated tumor suppressor miR-335 expression in different biological settings. Inhibition of miR-335 increased Tenascin C expression. Consequently, AHCC may influence BCSCs through miRNA pathways.
162

Extraction and Purification of Biologically Active Metabolites from Rhodococcus sp. MTM3W5.2

Alenazi, Mohrah 01 December 2018 (has links)
Rhodococcushas been recognized as a potential antibiotic producer. Recently, a strain of Rhodococcussp. MTM3W5.2 was isolated from a soil sample collected in Morristown, Tennessee and was found to produce an inhibitory compound which is active against other related species. The purpose of this research is to extract, purify and analyze the active metabolite. The compound was extracted from RM broth cultures and purified by preliminary fractionation of crude extract through a Sephadex LH-20 column. Further purification was completed using semi-preparative reversed phase column chromatography. Final purification was obtained using multiple rounds of an analytical C18 HPLC column. Based on the results achieved in the UV-Vis spectroscopy and high-resolution mass spectroscopy, the two desired compounds at a retention time of at 57 and 72 min could be polyketides with the molecular formulas C52H78O13 and C19H32O1N1/C13H34O1N1, respectively.
163

Total syntheses of sanggenon-type natural products and rearrangements of 3-substituted flavone ethers

Xiong, Yuan 22 January 2016 (has links)
An efficient approach to the hydrobenzofuro[3,2-b]chromenone core of sanggenon-type natural products has been developed. The key transformation involves a protecting group-free double rearrangement of a bis-allyloxyflavone ether substrate. A sequence involving asymmetric 3-allyl rearrangement followed by aromatic Claisen rearrangement has been established for the asymmetric synthesis of the hydrobenzofuro[3,2-b]chromenone core structure. This methodology has been successfully applied to asymmetric syntheses of both sanggenol F and sanggenon A. Efficient chiral, racemic syntheses for sanggenons C and O have been achieved. The key transformation entails a biomimetic Diels-Alder cycloaddition between a flavonoid diene and a 2'-hydroxychalcone. The flavonoid diene was produced from a protected flavonoid chromene via isomerization. Metal-catalyzed alkynyl Claisen (Saucy-Marbet) rearrangements of 3-alkynyl flavone ethers have been evaluated, and a 1,2-acyl migration cascade which afforded novel furanyl benzofuranone scaffolds was discovered. Mechanistic studies have revealed that the rearrangement is likely initiated by 5-endo enyne cyclization to a platinum-containing spiro-oxocarbenium intermediate, which may be intercepted by methanol to produce a spirodihydrofuran or further rearranged to afford allenyl chromanediones and benzofuranones at higher reaction temperature. Lewis acid-catalyzed [1,3]-rearrangements of 3-aryl substituted flavone ethers have also been developed.
164

Development of a Screening Process from Virtual Mirror-image Library of Natural Products Using D-Protein Technology / 鏡像体タンパク質を用いた天然物の鏡像体群からの医薬品探索法の開発

Noguchi, Taro 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(薬科学) / 甲第20312号 / 薬科博第81号 / 新制||薬科||9(附属図書館) / 京都大学大学院薬学研究科医薬創成情報科学専攻 / (主査)教授 大野 浩章, 教授 高須 清誠, 教授 竹本 佳司 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM
165

Studies on saccharothriolides, phenyl-substituted 10-membered macrolides from a rare actinomycete Saccharothrix sp. and precursor-directed in situ synthesis of saccharothriolide analogs / 希少放線菌Saccharothrix sp.が産生する新規saccharothriolide類とPDSSに関する研究

Shan, Lu 23 March 2017 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(薬科学) / 甲第20315号 / 薬科博第84号 / 新制||薬科||9(附属図書館) / 京都大学大学院薬学研究科医薬創成情報科学専攻 / (主査)教授 掛谷 秀昭, 教授 高須 清誠, 教授 大野 浩章 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM
166

Synthetic Studies of Peptide-Polyketide Hybrid Natural Products, Odoamide and Stereocalpin A / ペプチド─ポリケチド複合型天然物OdoamideおよびStereocalpin Aの合成研究

Kaneda, Masato 26 March 2018 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(薬科学) / 甲第21049号 / 薬科博第92号 / 新制||薬科||10(附属図書館) / 京都大学大学院薬学研究科医薬創成情報科学専攻 / (主査)教授 大野 浩章, 教授 竹本 佳司, 教授 高須 清誠 / 学位規則第4条第1項該当 / Doctor of Pharmaceutical Sciences / Kyoto University / DFAM
167

Rhodium-Catalyzed Decomposition of Carbohydrate Diazo Esters

LaLama, Matthew 01 August 2018 (has links)
No description available.
168

Organic Synthesis of Kaurenoic Acid

Williamson, Emily R. 26 May 2020 (has links)
No description available.
169

Isolation and Structural Determination of Bioactive Metabolites from the Soil Bacterium, Arthrobacter sp. TAJX1902

Arije, Amonah 01 August 2023 (has links) (PDF)
As antimicrobial resistance persistently disrupts the treatment of microbial infection, natural product chemistry has played a significant role in identifying novel drugs with novel modes of action critical to getting ahead of resistance. The primary goal of this project is to extract and identify potential novel antimicrobial natural products produced by Arthrobacter sp. Although underexplored, Arthrobacter sps. have been known to produce bioactive compounds with versatility; one such is a depsipeptide with quorum-sensing inhibitory activity.1 In this research, an Arthrobacter sp. TAJX1902, isolated from a soil sample, showed inhibitory activity against a filamentous indicator bacterium and a violacein-producing Janthinobacterium sp. Arthrobacter sp. TAJX1902 was cultured using rich medium broth and agar to extract and isolate metabolites. Isolated compounds were characterized via spectroscopic techniques, including 1D and 2D-NMR spectroscopy and GCMS analysis. Arthrobacter sp. TAJX1902 produces Pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(phenylmethyl), and five other bioactive cyclic dipeptides (CDPs).
170

<strong>THE DEVELOPMENT OF A MOLECULAR PROBE CAPABLE OF IDENTIFYING NATURAL PRODUCTS CONTAINING FURAN MOIETIES</strong>

Alyssa September Eggly (16640802) 08 August 2023 (has links)
<p>Natural products, along with natural product derivatives, are known to be at the root of the development of many pharmaceuticals, oftentimes showing unique bioactivity against interesting targets. Specifically, natural products containing furans show activity against a variety of diseases including fungal infections, and cancers. It is hypothesized that unknown natural products containing furans could show more potent or other biological activities. However, it is challenging to discover and isolate these small molecules from cell supernatant. The work described herein showcases the development of a molecular probe that can covalently attach to furan moieties via a [4 + 2] Diels-Alder cycloaddition, making them easily identifiable on liquid chromatography mass spectroscopy (LC-MS). The molecular probe, which undergoes this reaction with a variety of furans, was designed with both a UV-tag and a mass tag to enable easy identification. The probe has been tested with a variety of purified furans, including natural products, methylenomycin furan (MMF) hormones, and MMF derivatives. Moreover, work has begun to test the molecular probe in cell supernatants. </p>

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