21 |
Strategien zur Charakterisierung von ausgesuchten Streptomyces lividans Genen und deren FunktionenOverbeck, Jens 16 October 2007 (has links)
Das lineare Chromosom von S.lividans zeichnet sich durch eine hohe Variabilität insbesondere der chromosomalen Endbereiche aus. Hier finden sich unter anderen auch verschiedene Gene, die bisher einzigartig sind. Nach Klonierung der Gene in E.coli wurden die entsprechenden Genprodukte als His-Tag Fusionsproteine überproduziert, aufgereinigt und zur Herstellung von Antikörpern verwendet. Der untersuchte Abschnitt, als Ganzes und in Unterabschnitten, wurde auf einem Hoch Kopien Vektor in S.lividans transformiert. In extra hierfür konstruierten Vektorsystemen erfolgte die Produktion von His-Tag Proteinen in S.lividans. Nach Fusion von potentiellen Promoterbereichen mit dem promoterlosen EGFP-Gen, gelang deren Identifizierung in enhanced green fluorescent protein (EGFP) produzierenden S.lividans Transformanten. Mit Hilfe eines Vektors, der ein Temperatur sensitives Replikon besitzt, wurden Gene durch die Integration eines Hygromycin-Resistenzgenes ersetzt, bzw. als Fusionsgen mit dem EGFP-Gen erstellt. Ein Flavoprotein wurde zur Homogenität gereinigt. Es wurde nachgewiesen, dass in S.lividans pro Monomer ein FAD-Molekül interagiert. Physiologische Studien zeigen, dass die Synthese des chromosomal determinierten Proteins in S.lividans nur erfolgt, wenn dieser Stamm ein Plasmid- oder chromosomal- kodiertes Thiostrepton Resistenzprotein (23S rRNA Methylase) enthält. Es muss geschlussfolgert werden, dass die Methylierung der 23S rRNA die Translation verschiedener mRNAs beeinflusst. Die Synthese dieses Proteins ist des Weiteren abhängig von hohen Konzentrationen an NaCl und KCl im Medium, wie auch die zweier Aldo-Keto Reduktasen. Disruptionsmutanten eines dieser zwei Aldo-Keto Reduktase-Gene zeigen jeweils eine erhöhte und verfrühte Produktion eines rot gefärbten Mycel-assoziierten Antibiotikums (Undecylprodigiosin), während die eines weiteren (Actinorhodin) unbeeinflusst blieb.
|
22 |
Studies on Structure-Function Relationship and Conversion of Coenzyme Requirement in Bacterial α-Keto Acid Reductases Responsible for Metabolism of Acidic Polysaccharides / 酸性多糖の代謝に関わる細菌α-ケト酸還元酵素の構造機能相関と補酵素要求性変換に関する研究Takase, Ryuichi 25 May 2015 (has links)
京都大学 / 0048 / 新制・課程博士 / 博士(農学) / 甲第19195号 / 農博第2134号 / 新制||農||1034(附属図書館) / 学位論文||H27||N4941(農学部図書室) / 32187 / 京都大学大学院農学研究科食品生物科学専攻 / (主査)教授 谷 史人, 教授 保川 清, 准教授 橋本 渉 / 学位規則第4条第1項該当 / Doctor of Agricultural Science / Kyoto University / DFAM
|
23 |
Synthesis of Functionalized δ-Hydroxy-β-keto Esters and Evaluation of Their Anti-inflammatory PropertiesGrosse, Michel, Günther, Kerstin, Jordan, Paul M., Roman, Dávid, Werz, Oliver, Beemelmanns, Christine 27 July 2023 (has links)
δ-Hydroxy-β-keto esters and δ,β-dihydroxy esters are characteristic
structural motifs of statin-type natural products and drug
candidates. Here, we describe the synthesis of functionalized δ-
hydroxy-β-keto esters in good yields and excellent enantioselectivities
using Chan’s diene and modified Mukaiyama-aldol
reaction conditions. Diastereoselective reduction of δ,β-dihydroxy
esters afforded the respective syn- and anti-diols, and
saponification yielded the corresponding acids. All products
were evaluated for their anti-inflammatory properties, which
uncovered a surprising structure-activity relationship.
|
24 |
Chemopreventive Effects of Dietary Selenium and Soy Isoflavones in a Mouse Model of Prostate CancerQuiner, Trevor Elisha 30 June 2010 (has links) (PDF)
Prostate cancer is the most commonly diagnosed non-skin cancer in men and the second leading cause of cancer death in the United States. Prostate cancer, like many cancers, is a disease that generally requires a long period of time to develop and grow before it becomes detectable. This long period of latency makes prostate cancer a candidate for dietary chemoprevention. Soy and selenium (Se), are associated with a decreased risk of prostate cancer. We previously showed that high dietary intake of selenium (Se) and soy isoflavones decreased the expression of the androgen receptor (AR) and AR-regulated genes in the prostates of healthy rats. In this study we hypothesized that the downregulation of AR and AR-regulated genes would inhibit tumorigenesis in the transgenic adenocarcinoma of the mouse prostate (TRAMP) mouse. Mice were fed one of two stock diets with or without a supplement of Se in a 2 X 2 factorial design. The stock diets provided high or low dietary isoflavones. Mice were exposed to the diets from conception and sacrificed at 18 or 24 weeks of age. Prostate histopathology, urogenital tract (UGT) weight, serum IGF-1 levels, and the expression of AR and AR-regulated genes in the dorsolateral prostate was examined using quantitative PCR and Western blotting. Urogenital tract (UGT) weight was reduced compared to control in all dietary groups containing high Se, isoflavones, or both at 24 weeks (p<0.005). Dietary isoflavones delayed tumor progression and downregulated protein levels of AR, AR-regulated genes, and upregulated the protective FOXO1 and FOXO3a transcription factors. High dietary isoflavones also decreased the phosphorylation of the IGF-1R. The only main effect of Se was the upregulation of AKR1C14 the enzyme that deactivates 5&aplha;-DHT.This study identifies a previously unknown effect of isoflavones in the upregulation of FOXO expression and confirms previous studies of isoflavones' anticancer effects. Further research is needed to find a protective dose or form of Se and to elucidate the mechanism of isoflavones.
|
25 |
Nutritional Messaging: To Eat or Not to Eat?Triptow, Christina 31 March 2022 (has links)
There is a great deal of diet-specific processed foods on the market today. With so many options it can become difficult for consumers to decide what products to purchase. This situation is further intensified by the plethora of contradictory messages found in food advertising, especially in weight loss and dieting food advertising, but also seen in government nutrition campaigns and all over the internet on platforms like social media, blogs, and so forth. These messages can be confusing and frustrating for consumers as they try to decipher which foods they should eat to reach their health or weight loss goals. The purpose of this study was to determine if these contradictory messages extend to the advertising claims found on diet-specific food product packaging. A content analysis was performed on 400 keto and vegan products to uncover the most commonly used advertising claims and verify their accuracy based on the information provided on the nutrition label and ingredients list. An analysis of the health impacts of nutrient content and food additives based on FDA guidelines was also conducted. Results indicated that contradictory messages do extend to the advertising claims on keto and vegan food product packaging and the lack of healthy food options among these products should be a concern for consumers. This study highlights the importance of shoppers approaching food product advertising claims with skepticism until they can be verified.
|
26 |
The Production of 2-Keto-L-Gulonic Acid by Different Gluconobacter StrainsNassif, Lana Amine 14 February 1997 (has links)
Vitamin C is industrially produced by the Reichstein method, which uses gluconobacters to oxidize sorbitol to sorbose then a chemical process to convert sorbose to 2-keto-L-gulonic acid (2-KLG). The establishment of a more extensive microbial process for 2-KLG production translates into a less expensive and more efficient production of vitamin C. I examined pure strains and mixed cultures for their ability to produce 2-KLG using thin layer and high performance liquid chromatography. The DSM 4027 mixed culture produced the highest yield, 25 g/L, of 2-KLG from 100 g/L of sorbose, while the gram-negative rods isolated from DSM 4027 produced 8.8 g/L, and B. megaterium isolated from DSM 4027 produced 1.4 g/L. Thus, the gram-negative rods in the mixed culture were the primary 2-KLG producer, but B. megaterium in the DSM 4027 mixture enhanced this synthesis. Authentic pure cultures of Gluconobacter oxydans IFO strain 3293 and ATCC strain 621 produced 3.4 g/L and 5.7 g/L, respectively. Attempts to co-culture the isolated B. megaterium with the isolated gram-negative rods and authentic Gluconobacter strains did not increase 2-KLG production, nor did growing the cultures on B. megaterium spent media. Bacillus megaterium produced an unidentified keto-compound detected on the TLC chromatograms, which suggested that B. megaterium converted sorbose to an intermediate that may then be converted by the gram-negative rods in DSM 4027 to 2-KLG. Limited phenotypic tests suggested that the gram-negative rods in the DSM 4027 mixture are not gluconobacters. / Master of Science
|
27 |
Hydroxytriazole derivatives as potent and selective aldo-keto reductase 1C3 (AKR1C3) inhibitors discovered by bioisosteric scaffold hopping approachPippione, A.C., Giraudo, A., Bonanni, D., Carnovale, I.M., Marini, E., Cena, C., Costale, A., Zonari, D., Pors, Klaus, Sadiq, Maria, Boschi, D., Oliaro-Bosso, S., Lolli, M.L. 24 August 2017 (has links)
Yes / The aldo-keto reductase 1C3 isoform (AKR1C3) plays a vital role in the biosynthesis of androgens, making this enzyme an attractive target for castration-resistant prostate cancer therapy. Although AKR1C3 is a promising drug target, no AKR1C3-targeted agent has to date been approved for clinical use. Flufenamic acid, a non-steroidal anti-inflammatory drug, is known to potently inhibit AKR1C3 in a non-selective manner as COX off-target effects are also observed. To diminish off-target effects, we have applied a scaffold hopping strategy replacing the benzoic acid moiety of flufenamic acid with an acidic hydroxyazolecarbonylic scaffold. In particular, differently N-substituted hydroxylated triazoles were designed to simultaneously interact with both subpockets 1 and 2 in the active site of AKR1C3, larger for AKR1C3 than other AKR1Cs isoforms. Through computational design and iterative rounds of synthesis and biological evaluation, novel compounds are reported, sharing high selectivity (up to 230-fold) for AKR1C3 over 1C2 isoform and minimal COX1 and COX2 off-target inhibition. A docking study of compound 8, the most interesting compound of the series, suggested that its methoxybenzyl substitution has the ability to fit inside subpocket 2, being involved in π-π staking interaction with Trp227 (partial overlapping) and in a T-shape π-π staking with Trp86. This compound was also shown to diminish testosterone production in the AKR1C3-expressing 22RV1 prostate cancer cell line while synergistic effect was observed when 8 was administered in combination with abiraterone or enzalutamide. / University of Turin (Ricerca Locale grant 2014 and 2015) and Prostate Cancer UK grant S12-027
|
28 |
New aldo-keto reductase 1C3 (AKR1C3) inhibitors based on the hydroxytriazole scaffoldPippione, A.C., Kilic-Kurt, Z., Kovachka, S., Sainas, S., Rolando, B., Denasio, E., Pors, Klaus, Adinolfi, S., Zonari, D., Bagnati, R., Lolli, M.L., Spyrakis, F., Oliaro-Bosso, S., Boschi, D. 20 July 2022 (has links)
Yes / The aldo-keto reductase 1C3 (AKR1C3) enzyme is considered an attractive target in Castration Resistant Prostate Cancer (CRPC) because of its role in the biosynthesis of androgens. Flufenamic acid, a non-selective AKR1C3 inhibitor, has previously been subjected to bioisosteric modulation to give rise to a series of compounds with the hydroxytriazole core. In this work, the hit compound of the previous series has been modulated further, and new, more potent, and selective derivatives have been obtained. The poor solubility of the most active compound (cpd 5) has been improved by substituting the triazole core with an isoxazole heteronucleous, with similar enzymatic activity being retained. Potent AKR1C3 inhibition is translated into antiproliferative effects against the 22RV1 CRPC cellular model, and the in-silico design, synthesis and biological activity of new compounds is described herein. Compounds have also been assayed in combination with two approved antitumor drugs, abiraterone and enzalutamide. / This research was financially supported by the University of Turin (Ricerca Locale grants BOSD_RILO_20_01, LOLM_RILO_21_01, PIPA_RILO_20_01 and PIPA_RILO_21_01), Fondazione Cassa di Risparmio di Torino (Grant BOSD_CRT_17_2) and TUBITAK (The Scientific and Technological Research Council of Turkey-2219 program).
|
29 |
Caminhos sintéticos para obtenção de ésteres e tioésteres - α-metilsulfonil-α-metiltio-substituídos, precursores dos derivados α-ceto-carbocxílicos correspondentes / Synthetic pathways for obtaining esters and thioesters--methylsulfonyl--methylthio-substituted, precursors of the alpha-keto-carboxylic derivatives correspondingDonnici, Claudio Luis 02 April 1993 (has links)
Este trabalho apresenta: 1) Duas revisões bibliográficas sendo uma sobre a síntese de α-ceto-tioésteres e -ésteres e a outra sobre a decomposição de sulfóxidos e sulfonas sulfeniladas; 2) Investigações prévias indicando a viabilidade da decomposição térmica e a estabilidade relativa dos derivados bissulfenilados de tioésteres de diferentes estados de oxidação Ia-e, obtidos a partir do α-ceto-tioéster; 3) O estudo de síntese de precursores de α-ceto-tioésteres II e α-ceto-ésteres III, a saber: α - metilsulfonil- α - metiltio tioésteres IVa-c, -éster V e α, α - dimetiltio - ésteres VIa-c; 4) Decomposição térmica de α-metilsulfonil-α-metiltio-tioésteres Iva, b e c e -éster V sintetizados aos α-ceto-tioésteres e ésteres correspondentes, pelo emprego do método elaborado anteriormente por Wladislaw e col. e sugestão do mecanismo da mesma. A síntese de α metilsulfonil α metiltio tiopropionato de etila (Ivb), foi efetuada a partir do ácido α-cloro propiônico através de quatro passos reacionais, a saber: sulfenilação por substituição, oxidação à sulfona , tioesterificação e sulfenilação pelo emprego de NaH/MeS02SMe em DMSO. A obtenção do α - benzil - α - metilsulfonil - α - metiltio - tioacetato de etila (Ivc) foi efetuada a partir de ácido α-cloro acético através de reações de sulfenilação por substituição oxidação à sulfona tioesterificação alquilação com brometo de benzila e NaH em DMSO e, finalmente, a sulfenilação que só foi possível com o emprego de N-metiltioftalimida. A síntese de α-metilsulfonil-α-metiltio-propionato de etila (V) foi efetuada a partir do α-metilsulfonil malonato VIIa pelo eemprego do método de descarbetoxilação sulfenilativa usando 1,4 diazabiciclo [2,2,2] octano (DABCO) em tolueno sob refluxo e MeSO2SMe. Os compostos VIIa,b e c foram preparados a partir dos malonatos de dietila alquil - substituidos, seguido de sulfenilação e oxidação à sulfona. É de interesse a inédita reação de α - metilsulfonil fenilmalonato de dietila (VIIb), com DABCO em benzeno sob refluxo e MeSO2SMe, que conduziu à dessulfonilação sulfenilativa fornecendo o α - metiltio - fenilmalonato de dietila. É apresentada uma discussão mecanística tanto sobre descarbetoxilação, como sobre dessulfonilação sulfenilativas. A síntese de α,α-dimetiltio-ésteres VIa-c foi efetuada pela reação de sulfenilação com descarboxilação dos mono-ácidos malônicos correspondentes. O acompanhamento da descarboxilação e experimentos de deuteração permitiram esclarecer a sequência dos passos reacionais nestas novas reações. Cabe ressaltar que são compostos ainda não descritos na literatura os precursores IVa, IVb, IVc, V e Vib e 11 intermediários envolvidos nas reações efetuadas. Os resultados apresentados neste trabalho, além de importância sintética, trazem uma contribuição para a Química de Compostos Orgânicos de Enxofre. / This work presents: 1) Two literature reviews, one about the synthesis of α-keto thioesters and esters and the other on the decomposition of sulfenylated sulfoxides and sulfones; 2) Previous investigations indicating the viability of thermal decomposition and the relative stability of the dithioderivatives of different oxidation states Ia-e,which were obtained from the α-keto thioester; 3) The study of synthesis of α-keto thioesters II and esters III precursors, which are the following: α-methylsulfonyl-α-methylthio-thioesters IVa-c and -ester V, and α, α - dimethylthio esters VIa-c; 4) Thermal decomposition of the synthesized α - methylsulfonyl- α -methylthio- thioesters Iva,b e c and ester V, to the corresponding α-keto thioesters and α-keto ester, through the method developed by Wladislaw et al., with the suggestion of the mechanism. α-Methylsulfonyl-α-methylthio ethyl thiopropionate (Ivb) was synthesized from α-chloro-propionic acid in four steps: sulfenylative substitution, oxidation to sulfone, thioesterification and sulfenylation using NaH/MeSO2SMe in DMSO. α-Benzyl-α-methylsulfonyl-α-methylthio ethyl thioacetate (,i>Ivc) was obtained from α-chloro acetic acid through the following steps: sulfenylative substitution, oxidation to sulfone, thioesterification, alkylation with benzylbromide and NaH in DMSO, and finally, the sulfenylation which was successful only with the use of N-methylthiophtalimide. α-Methylsulfonyl-α-methylthio ethyl propionate (V) was synthesized through the sulfenylative decarbethoxylation of α methylsulfonyl diethyl malonate VIIa employing DABCO (1,4-diazabicyclo [2.2.2.]octane), in refluxing toluene, and MeSO2Sme. The compounds VIIa,b e c were obtained by the alkylation of malonates, followed by sulfenylation and oxidation to sulfones. An interesting and novel reaction, the sulfenylative desulfonylation, was observed when α-methylsulfonyl phenyldiethyl malonate (VIIb) was treated with DABCO, in refluxing benzene and MeSO2SMe, which led to the α-methylthio diethyl malonate. A mechanistic discussion about the sulfenylative decarbethoxylation and sulfenylative desulfonylation is presented. α, α-dimethylthio esters VIa-c were synthesized by sulfenylation and decarboxylation of the corresponding malonic half-esters. The sequence of the steps of this new reaction could be determined by deuteration experiments and by following the evolution of CO2. The precursors IV, IVb, IVc, V e Vib and 11 intermediates were unknown compounds. This work, besides the synthetical importance, presents some contribution to the Organosulfur Chemistry.
|
30 |
Идентификација и анализа потенцијалних супстрата и инхибитора хуманих протеина подфамилије 1С алдо-кето редуктаза (AKR1C) добијених рекомбинантном експресијом / Identifikacija i analiza potencijalnih supstrata i inhibitora humanih proteina podfamilije 1S aldo-keto reduktaza (AKR1C) dobijenih rekombinantnom ekspresijom / Identification and analysis of potential substrates and inhibitors of human protein subfamily 1C aldo-keto reductase (AKR1C) obtained by recombinant expressionPlavša Jovana 15 March 2019 (has links)
<p>Истраживање има фокус на хуманим ензимима из суперфамилије алдо-кето редуктаза, које имају велики метаболички значај за хомеостатско функционисање организма. Неки од чланова подфамилије 1С алдо-кето редуктаза (AKR1C) имају улогу у развоју одређених патолошких стања, као што су леукемија, тумори простате,<br />дојке и ендометријума, као и у смањивању ефекта хемотерапија. До сада није регистрован лек који директно утиче на протеине ове групе и самим тим је акценат на изналажењу специфичних лиганада (супстрата, инхибитора), који би могли да имају фармаколошку примену, али и на утврђивању везе између структуре и функције испитиваних лиганада према ензиму. Теза је имала фокус на протеину<br />AKR1C3. У овој дисертацији је представљена оптимизација ензимског есеја и испитивање потенцијалних лиганада и њиховог ефекта на ензимску активност одређених хуманих изоформи протеина из подфамилије AKR1C. Тестирана су синтетисанa стероиднa jeдињења, комерцијална једињења и биљни екстракти. Стероидни лиганди (<strong>AKR-1, -2, -3, -7, -9, -19</strong> и <strong>-22</strong>) који су показали добре инхибиторне карактеристике су детаљније описани одређеним добијеним<br />кинетичким параметрима и затим су кокристализовани са протеином и<br />кофакторм. Од 7 различитих комплекса протеина са најбољиминхибитором, за два комплекса су добијене дифракције са инхибитором и решене кристалне структуре са лигандом у везном месту и врло добром резолуцијом, <strong>AKR-7: 1.7 Å, AKR -19: 1.6 Å.</strong> Ови резултати представљају прве протеинске кристале чију су структуру решили истраживачи из Србије, а у научном смислу и одличну основу за даљи дизајн и тестирање једињења и кокристализације.</p> / <p>Istraživanje ima fokus na humanim enzimima iz superfamilije aldo-keto reduktaza, koje imaju veliki metabolički značaj za homeostatsko funkcionisanje organizma. Neki od članova podfamilije 1S aldo-keto reduktaza (AKR1C) imaju ulogu u razvoju određenih patoloških stanja, kao što su leukemija, tumori prostate,<br />dojke i endometrijuma, kao i u smanjivanju efekta hemoterapija. Do sada nije registrovan lek koji direktno utiče na proteine ove grupe i samim tim je akcenat na iznalaženju specifičnih liganada (supstrata, inhibitora), koji bi mogli da imaju farmakološku primenu, ali i na utvrđivanju veze između strukture i funkcije ispitivanih liganada prema enzimu. Teza je imala fokus na proteinu<br />AKR1C3. U ovoj disertaciji je predstavljena optimizacija enzimskog eseja i ispitivanje potencijalnih liganada i njihovog efekta na enzimsku aktivnost određenih humanih izoformi proteina iz podfamilije AKR1C. Testirana su sintetisana steroidna jedinjenja, komercijalna jedinjenja i biljni ekstrakti. Steroidni ligandi (<strong>AKR-1, -2, -3, -7, -9, -19</strong> i <strong>-22</strong>) koji su pokazali dobre inhibitorne karakteristike su detaljnije opisani određenim dobijenim<br />kinetičkim parametrima i zatim su kokristalizovani sa proteinom i<br />kofaktorm. Od 7 različitih kompleksa proteina sa najboljiminhibitorom, za dva kompleksa su dobijene difrakcije sa inhibitorom i rešene kristalne strukture sa ligandom u veznom mestu i vrlo dobrom rezolucijom, <strong>AKR-7: 1.7 Å, AKR -19: 1.6 Å.</strong> Ovi rezultati predstavljaju prve proteinske kristale čiju su strukturu rešili istraživači iz Srbije, a u naučnom smislu i odličnu osnovu za dalji dizajn i testiranje jedinjenja i kokristalizacije.</p> / <p>This research focuses on human enzymes of the aldo-keto reductase superfamily, whose functions have a significant metabolic impact on organism homeostasis. Some members of the 1C aldo-keto reductase (AKR1C) subfamily play role in the development of specific pathological conditions, such as leukaemia, prostate cancer, breast cancer and endometrial cancer, as well as reducing the effectivness of chemotherapy. However, currently there are no approved and registered drugs that directly affect proteins from this subfamily. Therefore our main aim was to screen for specific ligands (substrates, inhibitors) with potential pharmacological applications, and to establish structure-activity relationships for these ligands and enzymes. This thesis mainly focuses on isoform AKR1C3. In this dissertation, optimization of an enzymatic assay and testing of potential ligands and their effects on the enzymatic<br />activity of specific human isoforms of proteins from subfamily AKR1C are presented. Tested ligands include synthetic steroidal compounds, commercial compounds and plant extracts. Steroid compounds, <strong>AKR-1, -2, -3, -7, -9, -19</strong> and -<strong>22</strong>, were found to be good inhibitors of AKR1C3, and further kinetic studies were conducted. Finally, cocrystalization of protein AKR1C3 with cofactor and these inhibitors was accomplished. From 7 different complexes of protein with inhibitors, two structures were solved to very high resolution, <strong>AKR-7: 1.7 Å, AKR -19: 1.6 Å</strong>. These results represent the first protein crystal structures solved by researchers from Serbia, and results provide an excellent basis for further design and testing of new inhibitors.</p>
|
Page generated in 0.0287 seconds