Literatura académica sobre el tema "Isoprenoidi"
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Artículos de revistas sobre el tema "Isoprenoidi"
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Guggisberg, Ann M., Rachel E. Amthor y Audrey R. Odom. "Isoprenoid Biosynthesis in Plasmodium falciparum". Eukaryotic Cell 13, n.º 11 (12 de septiembre de 2014): 1348–59. http://dx.doi.org/10.1128/ec.00160-14.
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ABSTRACTMalaria kills nearly 1 million people each year, and the protozoan parasitePlasmodium falciparumhas become increasingly resistant to current therapies. Isoprenoid synthesis via the methylerythritol phosphate (MEP) pathway represents an attractive target for the development of new antimalarials. The phosphonic acid antibiotic fosmidomycin is a specific inhibitor of isoprenoid synthesis and has been a helpful tool to outline the essential functions of isoprenoid biosynthesis inP. falciparum. Isoprenoids are a large, diverse class of hydrocarbons that function in a variety of essential cellular processes in eukaryotes. InP. falciparum, isoprenoids are used for tRNA isopentenylation and protein prenylation, as well as the synthesis of vitamin E, carotenoids, ubiquinone, and dolichols. Recently, isoprenoid synthesis inP. falciparumhas been shown to be regulated by a sugar phosphatase. We outline what is known about isoprenoid function and the regulation of isoprenoid synthesis inP. falciparum, in order to identify valuable directions for future research.
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De Lillis, Manuela, Pietro Massimiliano Bianco y Francesco Loreto. "The influence of leaf water content and isoprenoids on flammability of some Mediterranean woody species". International Journal of Wildland Fire 18, n.º 2 (2009): 203. http://dx.doi.org/10.1071/wf07075.
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The impact of water content and isoprenoids on leaf flammability was studied. Field and laboratory experiments were carried out on monoterpene-emitting evergreen broad-leaved species (Quercus ilex, Quercus suber); a needle-leaved species (Pinus halepensis) that emits and stores monoterpenes; an evergreen species (Myrtus communis) that emits isoprene but stores monoterpenes; and a deciduous species (Quercus pubescens) that emits isoprene. Photosynthesis, leaf water content (LWC) and isoprenoid emission were measured. Isoprenoid content was calculated. Temperatures of visible smoke, incandescence and flame appearance were recorded. The LWC significantly correlated with both photosynthesis and isoprenoid emissions. Linear correlation and factorial analysis revealed a positive correlation between temperature of flame appearance and LWC and a negative relationship between temperature of flame appearance and isoprenoid emission. Multiple regression analysis indicated that the temperature of flame appearance was reduced in broadleaved monoterpene-emitting species. In monoterpene emitters, the temperature of flame appearance depended for ~65% on LWC, whereas monoterpene emissions explained ~35% of the dependency. P. halepensis and M. communis, storing high levels of isoprenoids, ignited at high humidity. The results may be explained if isoprenoids indeed facilitate leaf ignition but, being dissolved in water, isoprenoids are also an indicator of a high water content that decreases flammability.
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Chatzivasileiou, Alkiviadis Orfefs, Valerie Ward, Steven McBride Edgar y Gregory Stephanopoulos. "Two-step pathway for isoprenoid synthesis". Proceedings of the National Academy of Sciences 116, n.º 2 (24 de diciembre de 2018): 506–11. http://dx.doi.org/10.1073/pnas.1812935116.
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Isoprenoids comprise a large class of chemicals of significant interest due to their diverse properties. Biological production of isoprenoids is considered to be the most efficient way for their large-scale production. Isoprenoid biosynthesis has thus far been dependent on pathways inextricably linked to glucose metabolism. These pathways suffer from inherent limitations due to their length, complex regulation, and extensive cofactor requirements. Here, we present a synthetic isoprenoid pathway that aims to overcome these limitations. This isopentenol utilization pathway (IUP) can produce isopentenyl diphosphate or dimethylallyl diphosphate, the main precursors to isoprenoid synthesis, through sequential phosphorylation of isopentenol isomers isoprenol or prenol. After identifying suitable enzymes and constructing the pathway, we attempted to probe the limits of the IUP for producing various isoprenoid downstream products. The IUP flux exceeded the capacity of almost all downstream pathways tested and was competitive with the highest isoprenoid fluxes reported.
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Mu, Zhaobin, Joan Llusià y Josep Peñuelas. "Ground Level Isoprenoid Exchanges Associated with Pinus pinea Trees in A Mediterranean Turf". Atmosphere 11, n.º 8 (31 de julio de 2020): 809. http://dx.doi.org/10.3390/atmos11080809.
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The emissions of isoprenoids, a kind of biogenic volatile organic compounds (BVOCs), from soils is not well characterized. We quantified the exchange of isoprenoids between soil with litter and atmosphere along a horizontal gradient from the trunks of the trees, in a Mediterranean Pinus pinea plantation with dry and green needle litter to open herbaceous turf during mornings at mid-summer. Further, potential associated drivers were identified. Isoprenoid emissions were greatest and most diverse, and also can be roughly estimated by litter dry weight near the trunk, where the needle litter was denser. The composition of emitted isoprenoid by needle litter was different than the composition previously described for green needles. Low exchange rates of isoprenoids were recorded in open turf. Isoprenoid exchange rates were correlated positively with soil temperature and negatively with soil moisture. Given the variations in ground emissions with soil, vegetation, microorganisms, and associated interactions, we recommend widespread extensive spatio-temporal analysis of ground level BVOC exchanges in the different ecosystem types.
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Phulara, Suresh Chandra, Preeti Chaturvedi y Pratima Gupta. "Isoprenoid-Based Biofuels: Homologous Expression and Heterologous Expression in Prokaryotes". Applied and Environmental Microbiology 82, n.º 19 (15 de julio de 2016): 5730–40. http://dx.doi.org/10.1128/aem.01192-16.
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ABSTRACTEnthusiasm for mining advanced biofuels from microbial hosts has increased remarkably in recent years. Isoprenoids are one of the highly diverse groups of secondary metabolites and are foreseen as an alternative to petroleum-based fuels. Most of the prokaryotes synthesize their isoprenoid backbone via the deoxyxylulose-5-phosphate pathway from glyceraldehyde-3-phosphate and pyruvate, whereas eukaryotes synthesize isoprenoids via the mevalonate pathway from acetyl coenzyme A (acetyl-CoA). Microorganisms do not accumulate isoprenoids in large quantities naturally, which restricts their application for fuel purposes. Various metabolic engineering efforts have been utilized to overcome the limitations associated with their natural and nonnatural production. The introduction of heterologous pathways/genes and overexpression of endogenous/homologous genes have shown a remarkable increase in isoprenoid yield and substrate utilization in microbial hosts. Such modifications in the hosts' genomes have enabled researchers to develop commercially competent microbial strains for isoprenoid-based biofuel production utilizing a vast array of substrates. The present minireview briefly discusses the recent advancement in metabolic engineering efforts in prokaryotic hosts for the production of isoprenoid-based biofuels, with an emphasis on endogenous, homologous, and heterologous expression strategies.
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Choi, Bo Hyun, Hyun Joon Kang, Sun Chang Kim y Pyung Cheon Lee. "Organelle Engineering in Yeast: Enhanced Production of Protopanaxadiol through Manipulation of Peroxisome Proliferation in Saccharomyces cerevisiae". Microorganisms 10, n.º 3 (18 de marzo de 2022): 650. http://dx.doi.org/10.3390/microorganisms10030650.
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Isoprenoids, which are natural compounds with diverse structures, possess several biological activities that are beneficial to humans. A major consideration in isoprenoid production in microbial hosts is that the accumulation of biosynthesized isoprenoid within intracellular membranes may impede balanced cell growth, which may consequently reduce the desired yield of the target isoprenoid. As a strategy to overcome this suggested limitation, we selected peroxisome membranes as depots for the additional storage of biosynthesized isoprenoids to facilitate increased isoprenoid production in Saccharomyces cerevisiae. To maximize the peroxisome membrane storage capacity of S.cerevisiae, the copy number and size of peroxisomes were increased through genetic engineering of the expression of three peroxisome biogenesis-related peroxins (Pex11p, Pex34p, and Atg36p). The genetically enlarged and high copied peroxisomes in S.cerevisiae were stably maintained under a bioreactor fermentation condition. The peroxisome-engineered S.cerevisiae strains were then utilized as host strains for metabolic engineering of heterologous protopanaxadiol pathway. The yields of protopanaxadiol from the engineered peroxisome strains were ca 78% higher than those of the parent strain, which strongly supports the rationale for harnessing the storage capacity of the peroxisome membrane to accommodate the biosynthesized compounds. Consequently, this study presents in-depth knowledge on peroxisome biogenesis engineering in S.cerevisiae and could serve as basic information for improvement in ginsenosides production and as a potential platform to be utilized for other isoprenoids.
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Pérez-Gil, Jordi y Manuel Rodríguez-Concepción. "Metabolic plasticity for isoprenoid biosynthesis in bacteria". Biochemical Journal 452, n.º 1 (25 de abril de 2013): 19–25. http://dx.doi.org/10.1042/bj20121899.
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Isoprenoids are a large family of compounds synthesized by all free-living organisms. In most bacteria, the common precursors of all isoprenoids are produced by the MEP (methylerythritol 4-phosphate) pathway. The MEP pathway is absent from archaea, fungi and animals (including humans), which synthesize their isoprenoid precursors using the completely unrelated MVA (mevalonate) pathway. Because the MEP pathway is essential in most bacterial pathogens (as well as in the malaria parasites), it has been proposed as a promising new target for the development of novel anti-infective agents. However, bacteria show a remarkable plasticity for isoprenoid biosynthesis that should be taken into account when targeting this metabolic pathway for the development of new antibiotics. For example, a few bacteria use the MVA pathway instead of the MEP pathway, whereas others possess the two full pathways, and some parasitic strains lack both the MVA and the MEP pathways (probably because they obtain their isoprenoids from host cells). Moreover, alternative enzymes and metabolic intermediates to those of the canonical MVA or MEP pathways exist in some organisms. Recent work has also shown that resistance to a block of the first steps of the MEP pathway can easily be developed because several enzymes unrelated to isoprenoid biosynthesis can produce pathway intermediates upon spontaneous mutations. In the present review, we discuss the major advances in our knowledge of the biochemical toolbox exploited by bacteria to synthesize the universal precursors for their essential isoprenoids.
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Moehninsi, Iris Lange, B. Markus Lange y Duroy A. Navarre. "Altering potato isoprenoid metabolism increases biomass and induces early flowering". Journal of Experimental Botany 71, n.º 14 (16 de abril de 2020): 4109–24. http://dx.doi.org/10.1093/jxb/eraa185.
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Abstract Isoprenoids constitute the largest class of plant natural products and have diverse biological functions including in plant growth and development. In potato (Solanum tuberosum), the regulatory mechanism underlying the biosynthesis of isoprenoids through the mevalonate pathway is unclear. We assessed the role of 3-hydroxy-3-methylglutaryl-CoA reductase (HMGR) homologs in potato development and in the metabolic regulation of isoprenoid biosynthesis by generating transgenic lines with down-regulated expression (RNAi-hmgr) or overexpression (OE) of one (StHMGR1 or StHMGR3) or two genes, HMGR and farnesyl diphosphate synthase (FPS; StHMGR1/StFPS1 or StHMGR3/StFPS1). Levels of sterols, steroidal glycoalkaloids (SGAs), and plastidial isoprenoids were elevated in the OE-HMGR1, OE-HMGR1/FPS1, and OE-HMGR3/FPS1 lines, and these plants exhibited early flowering, increased stem height, increased biomass, and increased total tuber weight. However, OE-HMGR3 lines showed dwarfism and had the highest sterol amounts, but without an increase in SGA levels, supporting a rate-limiting role for HMGR3 in the accumulation of sterols. Potato RNAi-hmgr lines showed inhibited growth and reduced cytosolic isoprenoid levels. We also determined the relative importance of transcriptional control at regulatory points of isoprenoid precursor biosynthesis by assessing gene–metabolite correlations. These findings provide novel insights into specific end-products of the sterol pathway and could be important for crop yield and bioenergy crops.
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Junker-Frohn, Laura Verena, Anita Kleiber, Kirstin Jansen, Arthur Gessler, Jürgen Kreuzwieser y Ingo Ensminger. "Differences in isoprenoid-mediated energy dissipation pathways between coastal and interior Douglas-fir seedlings in response to drought". Tree Physiology 39, n.º 10 (1 de octubre de 2019): 1750–66. http://dx.doi.org/10.1093/treephys/tpz075.
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ABSTRACT Plants have evolved energy dissipation pathways to reduce photooxidative damage under drought when photosynthesis is hampered. Non-volatile and volatile isoprenoids are involved in non-photochemical quenching of excess light energy and scavenging of reactive oxygen species. A better understanding of trees’ ability to cope with and withstand drought stress will contribute to mitigate the negative effects of prolonged drought periods expected under future climate conditions. Therefore we investigated if Douglas-fir (Pseudotsuga menziesii(Mirb.)) provenances from habitats with contrasting water availability reveal intraspecific variation in isoprenoid-mediated energy dissipation pathways. In a controlled drought experiment with 1-year-old seedlings of an interior and a coastal Douglas-fir provenance, we assessed the photosynthetic capacity, pool sizes of non-volatile isoprenoids associated with the photosynthetic apparatus, as well as pool sizes and emission of volatile isoprenoids. We observed variation in the amount and composition of non-volatile and volatile isoprenoids among provenances, which could be linked to variation in photosynthetic capacity under drought. The coastal provenance exhibited an enhanced biosynthesis and emission of volatile isoprenoids, which is likely sustained by generally higher assimilation rates under drought. In contrast, the interior provenance showed an enhanced photoprotection of the photosynthetic apparatus by generally higher amounts of non-volatile isoprenoids and increased amounts of xanthophyll cycle pigments under drought. Our results demonstrate that there is intraspecific variation in isoprenoid-mediated energy dissipation pathways among Douglas-fir provenances, which may be important traits when selecting provenances suitable to grow under future climate conditions.
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DISCH, Andrea, Jörg SCHWENDER, Christian MÜLLER, Hartmut K. LICHTENTHALER y Michel ROHMER. "Distribution of the mevalonate and glyceraldehyde phosphate/pyruvate pathways for isoprenoid biosynthesis in unicellular algae and the cyanobacterium Synechocystis PCC 6714". Biochemical Journal 333, n.º 2 (15 de julio de 1998): 381–88. http://dx.doi.org/10.1042/bj3330381.
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Isopentenyl diphosphate, the universal isoprenoid precursor, can be produced by two different biosynthetic routes: either via the acetate/mevalonate (MVA) pathway, or via the more recently identified MVA-independent glyceraldehyde phosphate/pyruvate pathway. These two pathways are easily differentiated by incorporation of [1-13C]glucose and analysis of the resulting labelling patterns found in the isoprenoids. This method was successfully applied to several unicellular algae raised under heterotrophic growth conditions and allowed for the identification of the pathways that were utilized for isoprenoid biosynthesis. All isoprenoids examined (sterols, phytol, carotenoids) of the green algae Chlorella fusca and Chlamydomonas reinhardtii were synthesized via the GAP/pyruvate pathway, as in another previously investigated green alga, Scenedesmus obliquus, which was also shown in this study to synthesize ubiquinone by the same MVA-independent route. In the red alga Cyanidium caldarium and in the Chrysophyte Ochromonas danica a clear dichotomy was observed: as in higher plants, sterols were formed via the MVA route, whereas chloroplast isoprenoids (phytol in Cy. caldariumand O. danica and β-carotene in O. danica) were synthesized via the GAP/pyruvate route. In contrast, the Euglenophyte Euglena gracilis synthesized ergosterol, as well as phytol, via the acetate/MVA route. Similar feeding experiments were performed with the cyanobacterium SynechocystisPCC 6714 using [1-13C]- and [6-13C]-glucose. The two isoprenoids examined, phytol and β-carotene, were shown to have the typical labelling pattern derived from the GAP/pyruvate route.
Tesis sobre el tema "Isoprenoidi"
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Keim, Ana Verónica Beatriz. "Metabolismo lipídico en "Arabidopsis thaliana": Caracterización de mutantes "arv" y de las isoenzimas farnesildifosfato sintasa citosólicas Ana Verónica Beatriz Keim 2012". Doctoral thesis, Universitat de Barcelona, 2012. http://hdl.handle.net/10803/96118.
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Los estudios realizados sobre las proteínas Arv indican que estaría involucrada en la regulación de la homeostasis de esteroles y esfingolípidos. En levadura se observó una posible función en la síntesis de GPI (Kajiwara et al., 2008) y respecto a su topología, posee 3 dominios hidrofóbicos con el extremo N-terminal orientado hacia el citosol (Villasmil y Nickels 2011). En plantas, se caracterizaron los genes AtARV1 y AtARV2 de Arabidopsis thaliana que codifican dos proteínas de RE funcionales, AtArv1 y AtArv2. Estas comparten una identidad del 66% entre sí y poseen un dominio N-terminal AHD muy conservado en diferentes especies. Ambos genes poseen patrones solapantes de expresión en tejidos meristemáticos, excepto en hojas donde AtARV2 no se expresa (Forés et al., 2006). En este trabajo se determinó que AtArv1 posee un número par de dominios hidrofóbicos y que los extremos N- y C-terminales están orientados hacia el citosol. Además, se caracterizaron mutantes simples con pérdida de función (arv1) y dobles (arv1:arv2), que si bien no mostraron alteraciones fenotípicas, la activación de un RNAi en los doble mutantes arv1:arv2 indica que la pérdida de AtArv produce alteraciones fenotípicas en plántulas, que presentan acortamiento de la raíz y de los cotiledones que se vuelven amarillentos y se curvan en forma de « punta de flecha ». Los niveles de esteroles disminuyen y se ven incrementadas algunas BECL (Bases Esfingoides de Cadena Larga). Por otro lado, AtArv1 no parece estar vinculada a la UPR (Unfolded Protein Response) y su pérdida no es capaz de activar esta respuesta.
La farnesildifosfato sintasa (FPS) es una enzima dimérica que cataliza la condensación de una molécula de dimetilalildifosfato con dos moléculas de isopentenildifosfato para dar lugar a farnesildifosfato, que es el punto de partida para la síntesis de isoprenoides en el citosol y las mitocondrias. Los genes FPS1 y FPS2 de Arabidopsis thaliana codifican las isoenzimas FPS1L mitocondrial), FPS1S y FPS2. Las secuencias aminoacídicas de FPS1S y FPS2 poseen una identidad del 90.6% y difieren en sólo 32 aminoácidos. El gen FPS1 se expresa de forma generalizada durante todo el desarrollo de la planta, en cambio, FPS2 muestra un patrón de expresión restringido a órganos florales, semillas y estadios tempranos de la germinación. En la caracterización de los mutantes nulos de Arabidopsis fps1 y fps2 se observó que el gen FPS2 es más importante en las semillas y las etapas tempranas de la germinación. La isoenzima FPS2 contribuye entre un 70-80% a la actividad FPS total en semillas maduras. Como consecuencia, las semillas del mutante fps2 presentan niveles reducidos de sitosterol, un aumento de la actividad HMG-CoA reductasa (HMGR) e hipersensibilidad a la mevastatina (Closa et al., 2010). En este trabajo se ha determinado mediante ensayos bioquímicos, que la isoenzima FPS2 es catalíticamente más eficiente, más sensible al efecto inhibitorio del NaCl, y termodinámicamente más estable que FPS1S. También se ha demostrado la localización citosólica de ambas isoenzimas. Los patrones de expresión de los genes FPS1 y FPS2 son complementarios en semilla e indican que el FPP necesario para el desarrollo de las semillas tiene dos posibles orígenes separados en el espacio y en el tiempo. Por último, los estudios de complementación funcional en semillas del mutante fps2 demuestran que en condiciones normales FPS1S y FPS2 son funcionalmente intercambiables.The previously characterized Arabidopsis thaliana proteins AtArv1 and AtArv2 have been suggested to be involved in the regulation of cellular lipid homeostasis as demonstrated for their yeast and mammalian counterparts. In this study, we established the citosolic orientation of both N- and C-terminal ends of the AtArv1 protein in the yeast ER membrane. Functional complementation assays of an arv1Δ yeast strain with a truncated AtArv1 protein also showed that the C-terminal 31 aminoacids are essential for AtArv1 function. Characterization of single Arabidopsis arv mutants did not reveal any effect on plant phenotype. On the contrary, characterization of loss-of-function Arabidopsis arv1:arv2 double mutants obtained by inducible siRNA-mediated silencing of AtARV genes demonstrated that lack of AtArv function leads to reduced root lenght and pale green curved cotiledons as well as to reduced levels of major sterols and increased levels of some sphingolipid LCBs (Long Chain Bases). In contrast to S. cerevisiae Arv1p, AtArv is not involved in the UPR (Unfolded Protein Response) in Arabidopsis since lack of AtArv1 does not activate this response. Previous results obtained in our laboratory showed that Arabidopsis thaliana contains two genes encoding farnesyl diphosphate (FPP) synthase (FPS), the short-chain prenyl diphoshate synthase that catalyzes the synthesis of FPP from isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP). The FPS1 gene is widely expressed in all plant tissues throughout development, whereas FPS2 shows a pattern of expression restricted to specific floral organs, developing and mature seeds. Characterization of fps single knock-out mutants suggested that FPS2 has a major role in seeds and during the early stages of seedling development. Actually, FPS2 provides 70-80% of total FPS activity in mature Arabidopsis seeds, hence lack of FPS2 activity in seeds leads to a marked reduction in sitosterol content and a positive feedback regulatory response of HMG-CoA reductase (HMGR) activity that renders seeds hypersensitive to mevastatin. In this study, we provide evidence that the two Arabidopsis short FPS isozymes FPS1S and FPS2 localize to the cytosol. Biochemical characterization of these recombinant enzymes expressed in E. coli, revealed that, despite FPS1S and FPS2 share more than 90% amino acid sequence identity, FPS2 is more efficient as a catalyst, more sensitive to the inhibitory effect of NaCl, and more resistant to thermal inactivation than FPS1S. Expression analysis of FPS::GUS genes in seeds also showed that FPS1 and FPS2 display complementary patterns of expression particularly at late stages of seed development, which suggests that developping Arabidopsis seeds have two spatially segregated sources of FPP. Functional complementation studies of the fps2 knock-out mutant seed phenotypes demonstrated that at least under normal conditions FPS1S and FPS2 are functionally interchangeable.
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Lima, Valeria Bittencourt de. "Estudo fitoquimico de Himatanthus obovatus (Muell. Arg.) Woodson (APOCYNACEAE) : isolamento, elucidação estrutural e atividade biologica". [s.n.], 2005. http://repositorio.unicamp.br/jspui/handle/REPOSIP/249136.
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Orientador: Raquel Marques BragaTese (doutorado) - Universidade Estadual de Campinas, Instituto de Quimica
Made available in DSpace on 2018-08-04T22:47:27Z (GMT). No. of bitstreams: 1 Lima_ValeriaBittencourtde_D.pdf: 9598037 bytes, checksum: 83f061fb32519074a309e1975981ace5 (MD5) Previous issue date: 2005
Resumo: Nosso trabalho tem por objetivo o isolamento e a elucidação estrutural dos metabólitos secundários de Himatanthus obovatus (família Apocynaceae, sub-família Rauvolfioideae). Apenas cinco espécies de Himatanthus já foram estudadas do ponto de vista químico. O material de H. obovatus utilizado nesse trabalho foi coletado na Chapada dos Guimarães (MT) e em Casa Branca (SP). Utilizando diferentes metodologias de extração e tratamento dos extratos etanólicos brutos foram isoladas 5 lignanas: pinoresinol, isolariciresinol, hidroxipinoresinol, lariciresinol e olivil; 3 nor-isoprenóides: blumenol C, blumenol A e um nor-isoprenóide inédito; o iridóide plumieride, misturas dos terpenos: acetato de lupeol + acetato de a-amirina + acetato de b-amirina + germanicol e stigmasterol + b-sitosterol + campesteroI a, após a acetilação do extrato etanólico bruto, o glicitol inositol. Os extratos Diclorometânico (CDCb) e Etanólico (CECb) da casca de H. obovatus (Casa Branca (SP) foram submetidos aos testes com Artemia salina Leach. e de atividade antiproliferativa frente à 4 linhagens celulares derivadas de tumores humanos: leucemia (K562), pulmão (NCI460), melanoma (UACC62) e mama (MCF7). Os resultados dos dois testes foram bastante coerentes, já que ambos mostraram resultados promissores para o extrato CDCb. Os testes de bioautografia foram realizados com os extratos da casca de H. obovatus (Casa Branca): CHCb (heptano), CDCb (diclorometano) e CECb (etanol) e com as substâncias isoladas: pinoresinol, isolariciresinol, blumenol C, blumenol A, nor-isoprenóide inédito, hidroxipinoresinol, lariciresinol, plumieride e inositol, frente aos fungos: Alternaria alternata, Aspergillus fumigatus, A. niger, Candida albicans, Cladosporium cladosporioides, Fusarium oxysporium, Penicillium oxalicum, P. funicullosum e Rhizopus orizae. e frente às bactérias: Bacillus subtilis, Escherichia coli, Micrococcus luteus, Salmonella typhimurim, Staphilococcus aureus e Streptococcus mutans. Foram observadas atividades bactericida para as lignanas: isolariciresinol frente à bactéria S. mutans e lariciresinol frente à bactéria S. aureus. Os compostos isolados de H. obovatus permitiram comparar filogeneticamente este gênero aos gêneros Tabernaemontana e Rauvolfia (pertencentes às mesmas família e sub-família), estudados anteriormente em nosso grupo de pesquisas e ricos em alcalóides indólicos.
Abstract: Our objective is the isolation and identification of the compounds from Himatanthus obovatus (family Apocynaceae and sub-family Rauvolfioideae). Five species from genus Himatanthus have been chemically studied. H. obovatus was collected in Chapada dos Guimarães (MT state, Brazil) and in Casa Branca (SP State, Brazil). We used different methodologies for extraction and purification of the extracts, yielding 5 lignans: pinoresinol, isolariciresinol, hydroxypinoresinol, lariciresinol and olivil; 3 nor-isoprenoids: blumenol C, blumenol A and one unknown nor-isoprenoid; the iridoid plumieride, a mixture of terpenes: lupeol acetate + a-amirin acetate + b-amirin acetate + germanicol and stigmasterol + b-sitosterol + campesterol and, after acetylation of the crude ethanolic extract, the glycitol inositol. The diclorometanic (CDCb) and ethanolic (CECb) extracts trom the bark of H. obovatus (Casa Branca - SP) have been tested with Artemia salina Leach. and for antiproliferative activity against 4 carcinoma cell lines derived from human cancer: leukemia (K562), lung (NCI1460), melanoma (UACC62) and breast (MCF7). The good results with the CDCb extract in both tests suggest that this extract is a development candidate. The Bioautography tests were made with the heptanic (CHCb), diclorometanic (CDCb) and ethanolic (CECb) extracts from the bark of H. obovatus (Casa Branca - SP) and with the isolated substances: pinoresinol, isolariciresinel, blumenol C, blumenol A, the unknown nor-isoprenoid, hydroxypinoresinol, lariciresinol, plumieride and inositol against the fungi: Alternaria alternata, Aspergillus fumigatus, A. niger, Candida albicans, Cladosporium cladosporioides, Fusarium oxysporium, Penicillium oxalicum P. funicullosum and Rhizopus orizae and against the bacteria: Bacillus subtilis, Escherichia coli, Micrococcus luteus, Salmonella typhimurim, Staphilococcus aureus and Streptococcus mutans. We observed bactericide activity at the lignans: isolariciresinol against the bacteria S. mutans and lariciresinol against the bacteria S. aureus. The coumpounds isolated from H. obovatus allowed us to phylogenetically compare this genus to the genera Tabernaemontana and Rauvolfia (belonging to the same family and sub-family), previously studied in our group and rich in indolic alkaloids.
Doutorado
Quimica Organica
Doutor em Ciências
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Perez, Gil Jordi. "Biosíntesi d’isoprenoides en bacteris i plantes. Aproximacions biotecnològiques". Doctoral thesis, Universitat de Barcelona, 2013. http://hdl.handle.net/10803/101464.
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Els isoprenoides constitueixen una vasta família de compostos naturals que duen a terme una amplia varietat de funcions, moltes d’elles essencials, en els tres dominis de la vida. No obstant tots ells deriven d’una única molècula comú, el IPP (i el seu isòmer DMAPP) que es produeix a través de dues possibles rutes biosintètiques, la via del MEP i la via del MVA. La via MEP és la predominant en eubacteris mentre que la del MVA ho és en arqueobacteris, fongs i animals. En plantes coexisteixen les dues vies de forma compartimentalitzada. Aquesta distribució diferencial de les dues vies ha convertit la via MEP en una nova i prometedora diana per al disseny de nous antibiòtics (amb la FSM, un inhibidor específic de l’enzim DXR de la via MEP com a màxim exponent), molt necessaris en l’actualitat com a conseqüència de l’emergent resistència que han desenvolupat un gran nombre de microorganismes patògens a les drogues desenvolupades fins al moment. No obstant, tot i que el caràcter essencial dels isoprenoides fa que la seva síntesi es mantingui en tots els éssers vius la enorme plasticitat gènica, que es concentra especialment en bacteris, ha donat lloc a l’adopció d’estratègies alternatives tant a nivell d’enzims com metabòlits. Els carotenoides conformen una subfamília dintre dels isoprenoides de compostos derivats de la molècula parental de 40 carbonis, el fitoe, amb funcions que comprenen tant el metabolisme primari com el secundari. Es sintetitzen principalment en els plastidis de les plantes però també són produïts per alguns bacteris no fotosintètics i fongs. La seva creixent aplicació en la indústria ha fet molt atractiva l’aplicació de la biotecnologia per a la producció d’aquests compostos però per poder afrontar amb garanties aquest repte cal conèixer a fons els mecanismes que regulen a tots nivells la seva producció.
Al llarg d’aquest treball s’ha combinat l’estudi dels aspectes bàsics i aplicats de la síntesi d’isoprenoides amb especial èmfasi en el paper de la via del MEP i la biosíntesi de carotenoides per proposar i avaluar estratègies de millora de la seva producció tant en bacteris com en plantes. El treball ha permès testar l’us d’enzims bifuncionals per millorar simultaniàment dos passos catalítics de la ruta carotenogènica tant en sistemes bacterians com en plantes. Es va analitzar l’efecte de la fusió de LCYE i LCYB (ε-ciclasa i β-ciclasa respectivament) en expressar-la en un sistema model carotenogènic de E.coli o en plantes transgèniques d’Arabidopsis thaliana obtenint-se resultats positius en el primer cas però no en el segon. Aquesta diferència posa de manifest la major complexitat dels sistemes vegetals. En aquesta línia es va explorar el possible paper addicional de la regulació post-transcripcional en el control del flux de la via del MEP utilitzant un mutant (rif18) obtingut en base a un escrutini de resistència a la inhibició per FSM. L’estudi va posar de manifest un nivell de regulació com a resultat de la integració i coordinació de la ruta MEP amb la resta del metabolisme de la planta especialment els metabolismes del sucre i de les hormones.
Paral.lelament es va avaluar el paper que juguen individualment cada un dels enzims de la via MEP en el control del flux de la via en sistemes bacterians. L’estudi de la sobreexpressió de cada un dels gens en un sistema model carotenogènic de E.coli va posar de manifest el paper clau de DXS i la participació en menor mesura de DXR i HDR, resultats similars als descrits en Arabidopsis. Però, encara més important, va demostrar que uns nivells moderats de sobrexpressió dels enzims clau produeixen millors resultats en l’acumulació de productes finals. Complementariàment es va estudiar en profunditat el paper de HDS tant en bacteris com en plantes ja que havia estat descrit préviament com un possible punt de regulació diferencial entre els dos sistemes en base a les diferències observades en alineaments de seqüència. En cap dels dos casos un increment de l’activitat d’aquest enzim millorava l’acumulació de productes finals.
Els dos passos identificats com a claus en la ruta MEP (DXS i DXR) es van escollir com a objectius sobre els que, aprofitant la plasticitat gènica i metabòlica dels bacteris, cercar noves activitats alternatives. Per DXS es van identificar dues proteïnes de E.coli (E1-PDH i DHBPS) que en patir mutacions puntuals adquirien la capacitat de complementar la deficiència de DXS. Per identificar activitats alternatives a DXR es va analitzar la presència d’homòlegs pels 7 gens de la via MEP en els genomes seqüenciats de microorganismes. Es va identificar un grup en els que hi eren presents tots ells excepte DXR. Utilitzant el genoma de Brucella abortus es va identificar una proteïna sense homologia amb DXR (DRL) capaç de suplir-ne l’absència i que defineix una nova família de proteïnes la funció de les quals era desconeguda. La seva caracterització va mostrar que catalitza la mateixa reacció amb propietats cinètiques similars a les descrites per DXR però amb diferències significatives, com una menor eficiència catalítica o una menor sensibilitat a la inhibició per FSM. L’estudi filogènetic de la família va posar de manifest l’existència de DRL vertaderes (amb activitat DXR) que s’agrupaven en un mateix clade filogenètic i DRL falses definint a l’hora tres classes de proteïnes. La cristal.lització i resolució de l’estructura tridimensional de la proteïna DRL de Brucella abortus va permetre un estudi estructural comparatiu observant-se diferències significatives respecte DXR especialment en el reordenament del centre actiu. A partir d’aquestes diferències es va hipotetitzar, en base a modelitzacions in silico, la possibilitat d’inhibir diferencialment els dos enzims. Aquesta possibilitat es va confirmar en estudis d’inhibició in vitro amb les proteïnes DXR de E.coli, i DRL de B.abortus recombinants purificades. Els α-fenil derivats de la FSM mostraven una capacitat d’inhibició de DXR en l’ordre nanomolar mentre que no mostraven cap efecte sobre DRL a concentracions de fins a 1 mM obrint la porta al disseny de nous antibiòtics de gran especificitat.ISOPRENOIDS BIOSYNTHESIS IN BACTERIA AND PLANTS Isoprenoids are a vast family of natural compounds that perform a wide variety of biological functions, many of which are essential. However, they all derived from the universal intermediates IPP and its isomer DMAPP. Their biosynthesis occurs through two possible biosynthetic routes, the MEP and the MVA pathways. The MEP pathway is the exclusive source of IPP and DMAPP in eubacteria whereas the MVA pathway provides these precursors in archaea, fungi and animals. In plants, both pathways coexist in different subcelullar compartments. This distribution of isoprenoid biosynthetic pathways among the kingdoms has turned the MEP pathway into a promising new target for the design of new antibiotics (with FSM, a specific inhibitor of the enzyme DXR, as the main representative). Although isoprenoids are essential in all free-living organisms, tremendous plasticity among bacteria has led to the evolution of alternative biochemical strategies to produce these universal precursors. Carotenoids comprise a subfamily of C40 isoprenoid end products derived from a molecule of phytoene with functions in both primary and secondary metabolism. These are synthesized primarily in the plastids of plants but are also produced by some photosynthetic bacteria, fungi, and rarely in insects. The increasing use of carotenoids in the food, cosmetics and pharmaceutical industries as pigments, fragrances and nutraceuticals has galvanized their production through biotechnological applications. We have combined the study of basic and applied aspects of isoprenoid biosynthesis focusing on the role of the MEP pathway and carotenoid biosynthesis to suggest and evaluate strategies for improving their production in bacteria and plants. To this end, we have exploited the metabolic plasticity of bacteria to provide new biotechnological tools for carotenoid production. In the study, the use of bifunctional enzymes was tested to simultaneously improve two catalytic steps. As a proof of concept we analyzed the effect of chimeric LCYE-LCYB (ε-cyclase and β-cyclase, respectively) in a carotenogenic E. coli model system or in transgenic plants of Arabidopsis thaliana. The difference in the results highlights the major complexity of plant systems. In this direction, we studied the possible role of additional post-transcriptional regulation controlling the flow of the MEP pathway by using a mutant (rif18) isolated from a FSM-resistance screening. The study showed a higher level of regulation as a consequence of the integration and coordination with other metabolic pathways of the plant, especially the metabolism of sugars and hormones. We also evaluated the role of each of the individual enzymes of the MEP pathway in controlling the pathway flux in bacterial systems. Overexpresion of each individual gene in a carotenogenic E. coli model system highlighted the key role of DXS and to a lesser extent of the participation for DXR and HDR in driving flux through this pathway, in agreement with previous reports for Arabidopsis. Even more importantly, these results demonstrate that adjusted levels of overexpresion of the key enzymes produce better results in the accumulation of end products, the most relevant parameter for evaluating biotechnological strategies. Additionally, we further studied the role of HDS both in bacteria and plants. This enzyme had been previously postulated to have different regulatory roles in the two systems based on protein alignments. In both cases, an increase in enzyme activity does not affect the accumulation of end products. The identified key steps in the MEP pathway (DXS and DXR) were chosen as targets to search for new alternative activities taking advantage of the genetic and metabolic plasticity of bacteria. Two E.coli proteins which underwent change-of-function mutations in dxs or dxr deficient strains and acquired DXS activity were identified (DHBPS and PDH-E1). An alternative activity to DXR was identified by analyzing the sequenced genomes available from bacteria. A small group of microorganism contains homologous genes for all MEP pathway but DXR. Using the genome of Brucella abortus, a separate protein with no apparent homology to DXR (thereafter named DXR-like, or DRL) was identified. DRL defines a new family of proteins that catalyzes the first committed step of the MEP pathway. Characterization of the protein showed that it catalyzes the same reaction with similar kinetic properties as DXR albeit with significant differences in catalytic efficiency and lower sensitivity to inhibition by FSM. Phylogenetic and complementation studies of the family revealed the existence of true DRL (with DXR activity) grouped in the same phylogenetic clade. Crystallization and structural resolution of DRL from Brucella abortus allowed a comparative study. Significant differences to DXR were observed, in particular in the arrangement of the active site. Based on those differences and in silico modeling, the possibility to selectively inhibit either enzyme was hypothesized. In vitro inhibition studies using purified recombinant E. coli DXR and B.abortus DRL demonstrates that α-phenyl derivatives of FSM inhibit DXR in the nanomolar range while show no significant effect on DRL at a concentrations up to 1 mM. Those results open the door for the design of new highly specific antibiotics. The first tests in biotechnological applications comparing the ability of the three alternative proteins to replace the original DXS or DXR activities showed no improvement in performance. However, these proteins should be considered starting materials to continue the optimization of the new catalytic functions acquired using directed enzyme evolution methods in the laboratory.
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Milne, Keith Livingston. "Bacterial isoprenoid biosynthesis". Thesis, University of Edinburgh, 1990. http://hdl.handle.net/1842/11172.
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This thesis describes a possible alternative isoprenoid pathway in bacteria by considering some previously unpublished feeding studies in the context of the related background literature. Three synthetic routes to 2,4-dihydroxy-4-methyltetrahydropyran (63) and three synthetic strategies towards the synthesis of 2-carboxy-2,4-dihydroxy-4-methyltetrahydropyran (63) are discussed. These compounds are considered as potential intermediates in the proposed alternative bacterial isoprenoid pathway. Labelled synthesis of (63) and structural analysis of (63) and 4-hydroxy-2-methoxy-4-methyltetrahydropyran (99) by proton nmr are also described. Feeding studies including the 13C isotopically labelled tetrahydropyrans (63) and (99) are described and a revised interpretation of all of the feeding studies considered. HMGCoA synthase is assayed in Rh. capsulata after a description of its assay in bakers yeast.
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Ng, Khuen Yen Prince of Wales Medical Research Institute Faculty of Medicine UNSW. "Isoprenoids in Parkinson's disease". Awarded by:University of New South Wales. Prince of Wales Medical Research Institute, 2009. http://handle.unsw.edu.au/1959.4/44827.
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Parkinson???s disease (PD) is a progressive neurodegenerative disease characterised pathologically by the selective death of the dopaminergic neurons of the substantia nigra and the appearance of abnormal inclusions in some surviving neurons. A body of evidence from epidemiological, in vitro and in vivo studies suggest that isoprenoids, a lipid family which includes cholesterol, dolichol and ubiquinone, may play a role in PD, although to date the data has been conflicting with little consensus regarding the type or direction of change in isoprenoids in PD. The current study investigated isoprenoids in PD by quantifying a range of isoprenoids in blood sera, brain homogenates and olfactory mucosa derived from PD patients and controls. Further, isoprenoid synthesis pathways were investigated by comparing the activitites and amount of the rate-limiting enzyme for isoprenoid synthesis, HMG CoA reductase, in olfactory mucosal cultures from individuals with sporadic PD and leucine-rich repeat kinase 2 (LRRK2)-PD with those from healthy individuals. Serum levels of total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides and dolichol were unchanged in patients with PD compared with controls. Similarly, total tissue cholesterol was unchanged in degenerating and non-degenerating regions of the PD brain, but tissue dolichol was significantly decreased in the substantia nigra in the PD brain, possibly reflecting a change in the neuron/glia ratio in this brain region. In olfactory mucosa, a significant decrease in cellular cholesterol content was identified in patients with LRRK2-PD compared with patients with sporadic PD or controls. The reduction in cholesterol was similar in two different LRRK2 mutations but was not associated with a change in either the amount or activity of HMG CoA reductase. This study suggests that decreased cholesterol is associated with LRRK2-PD but not with sporadic PD. As cholesterol levels in cells with different LRRK2 mutations were reduced to a similar extent, it is suggested that mutations in this gene result in a loss-of-function of LRRK2 protein. Further it suggests a role for LRRK2 in cholesterol homeostasis independent of HMG-CoA reductase-associated pathways. Recent data has suggested a functional role of LRRK2 in autophagy, a mechanism which may explain the reduction in cholesterol observed in LRRK2-PD.
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Amslinger, Sabine. "Chemie und Immunbiologie von Intermediaten der Isoprenoidbiosynthese". [S.l. : s.n.], 2003. http://deposit.ddb.de/cgi-bin/dokserv?idn=969451997.
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Warzecha, Klaus-D. "Lichtinduzierter Elektronentransfer an isoprenoiden Polyalken-1, 1-Dicarbonitrilen zum Mechanismus photochemisch ausgelöster radikalischer Cyclisierungen /". [S.l. : s.n.], 2002. http://deposit.ddb.de/cgi-bin/dokserv?idn=966137434.
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Foster, Jeremy Michael. "Hormones and isoprenoids in trematodes". Thesis, University of Liverpool, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303679.
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Duvold, Tore. "Chemistry and biochemistry of bacterial isoprenoids". Université Louis Pasteur (Strasbourg) (1971-2008), 1997. http://www.theses.fr/1997STR13195.
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Il etait unanimement accepte que la biosynthese des isoprenoides passait par le mevalonate. Des etudes recentes ont revele l'existence d'une voie alternative independante du mevalonate passante par le glyceraldehyde 3-phosphate (gap) et la pyruvate via une condensation et un rearrangement. Nous avons etudie le role du 2-c-methyleerythritol comme precurseur dans cette voie. En effet, des incorporations de glucose marque au #1#3c ont montre que chez corynebacterium ammoniagenes les squelettes du methylerythritol et des unites isopreniques etait formes de la meme facon. L'incorporation de #2h-2-c-methyl-d-erythritol dans les isoprenoides d'escherichia coli a confirme le role de ce polyol ramifie comme precurseur de l'ipp. La bacterie zymomonas mobilis produit des hopanoides complexes. La conservation des deux atomes de deuterium sur le carbone c-31 apres incorporation du 6,6-#2h#2glucose indique qu'une reaction de substitution permet l'insertion de la chaine laterale en c#5. Les marquages de la squelette hopane a confirme l'intervention de la voie gap/pyruvate. Nous avons developpe une hemisynthese du ribosylhopane qui donne acces a des hopanoides qui pourrait etre des precurseurs des bacteriohopanepolyols ou des hopanoides avec des activites biologiques interessantes. Nous avons synthetise un analogue du bacteriohopanetetrol en serie sterane avec une chaine laterale c#5 polyhydroxylee lie au carbone c-3 en utilisant une strategie synthetique similaire a celle utilisee pour l'obtention du ribosylhopane. Cet analogue a ete propose comme precurseur biologique des 3-alkylsteranes et des 3-carboxyalkylsteranes, abondants dans les sediments et serait a rechercher dans des microorganismes.
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Grove, Joanna E. "Inhibition of isoprenoid biosynthesis by bisphosphonates". Thesis, University of Sheffield, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.301811.
Texto completoLibros sobre el tema "Isoprenoidi"
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Rodríguez-Concepción, Manuel, ed. Plant Isoprenoids. New York, NY: Springer New York, 2014. http://dx.doi.org/10.1007/978-1-4939-0606-2.
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Schrader, Jens y Jörg Bohlmann, eds. Biotechnology of Isoprenoids. Cham: Springer International Publishing, 2015. http://dx.doi.org/10.1007/978-3-319-20107-8.
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H, Law John y Rilling Hans C, eds. Steroids ans isoprenoids. Orlando: Academic Press, 1985.
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H, Law John y Rilling Hans C, eds. Steroids and isoprenoids. Orlando: Academic Press, 1985.
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Bach, Thomas J. y Michel Rohmer, eds. Isoprenoid Synthesis in Plants and Microorganisms. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-4063-5.
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David, Nes W., Parish Edward J, Trzaskos James M, American Chemical Society. Division of Agricultural and Food Chemistry. y American Chemical Society Meeting, eds. Regulation of isopentenoid metabolism. Washington, DC: American Chemical Society, 1992.
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Frenkel, Joost y Hans R. Waterham. Mevalonate Kinase Deficiency. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199972135.003.0039.
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Mevalonate kinase deficiency (MKD) is an autosomal recessive inborn error of isoprenoid biosynthesis, a pathway yielding sterols and nonsterol isoprenoids.In patients, the enzyme activity of mevalonate kinase is severely reduced due to mutations in the encoding gene, MVK. The substrate, mevalonate, accumulates and is elevated in blood and urine. Shortage of certain downstream products of the pathway, nonsterol isoprenoids, leads to dysregulation of the innate immune system, activation of inflammasomes, and interleukin (IL)-1 mediated inflammation.Symptoms start in early childhood with recurrent attacks of fever, vomiting, diarrhea, headache, sore throat, abdominal pain, arthralgias, painful lymphadenopathy, hepatosplenomegaly, skin rash, and mucosal ulcers. Severely affected patients have additional symptoms, such as intellectual impairment, progressive cerebellar ataxia, and tapetoretinal degeneration. Complications include intestinal obstruction, AA-amyloidosis, hemophagocytosis, and severe infection.Management of MKD is directed at controlling inflammation.
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Schrader, Jens y Jörg Bohlmann. Biotechnology of Isoprenoids. Springer, 2016.
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Schrader, Jens y Jörg Bohlmann. Biotechnology of Isoprenoids. Springer London, Limited, 2015.
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Schrader, Jens y Jörg Bohlmann. Biotechnology of Isoprenoids. Springer, 2015.
Buscar texto completoCapítulos de libros sobre el tema "Isoprenoidi"
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Schwarzbauer, Jan y Branimir Jovančićević. "Isoprenoids". En From Biomolecules to Chemofossils, 27–76. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-25075-5_3.
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Eigenbrode, Jennifer. "Isoprenoids". En Encyclopedia of Astrobiology, 1–2. Berlin, Heidelberg: Springer Berlin Heidelberg, 2014. http://dx.doi.org/10.1007/978-3-642-27833-4_823-3.
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Eigenbrode, Jennifer. "Isoprenoids". En Encyclopedia of Astrobiology, 1274–75. Berlin, Heidelberg: Springer Berlin Heidelberg, 2015. http://dx.doi.org/10.1007/978-3-662-44185-5_823.
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Hänsel, Rudolf y Josef Hölzl. "Isoprenoide". En Lehrbuch der pharmazeutischen Biologie, 63–125. Berlin, Heidelberg: Springer Berlin Heidelberg, 1996. http://dx.doi.org/10.1007/978-3-642-60958-9_3.
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Eigenbrode, Jennifer. "Isoprenoids". En Encyclopedia of Astrobiology, 859–60. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-11274-4_823.
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Katzin, Alejandro Miguel. "Isoprenoid Metabolism". En Encyclopedia of Malaria, 1–8. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-8757-9_11-1.
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Nguyen, Uyen T. T., Andrew Goodall, Kirill Alexandrov y Daniel Abankwa. "Isoprenoid Modifications". En Post-Translational Modifications in Health and Disease, 1–37. New York, NY: Springer New York, 2010. http://dx.doi.org/10.1007/978-1-4419-6382-6_1.
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Sandmann, Gerhard. "Carotenoids of Biotechnological Importance". En Biotechnology of Isoprenoids, 449–67. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/10_2014_277.
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Wüst, Matthias. "Advances in the Analysis of Volatile Isoprenoid Metabolites". En Biotechnology of Isoprenoids, 201–13. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/10_2014_278.
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Leonhardt, Robin-Hagen y Ralf G. Berger. "Nootkatone". En Biotechnology of Isoprenoids, 391–404. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/10_2014_279.
Texto completoActas de conferencias sobre el tema "Isoprenoidi"
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Vasilev, Dimitar y Ludger A. Wessjohann. "Synthesis of isoprenoid diphosphate mimetics". En 14th Brazilian Meeting on Organic Synthesis. São Paulo: Editora Edgard Blücher, 2013. http://dx.doi.org/10.5151/chempro-14bmos-r0387-1.
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Bieleń, W. y I. Matyasik. "Aryl Isoprenoids as Indicators of Photic Zone Anoxia". En 29th International Meeting on Organic Geochemistry. European Association of Geoscientists & Engineers, 2019. http://dx.doi.org/10.3997/2214-4609.201902983.
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Tabefam, M., M. Moridi Farimani, J. Ramseyer, O. Potterat y M. Hamburger. "New isoprenoids with rare scaffolds from Salvia hydrangea". En GA 2017 – Book of Abstracts. Georg Thieme Verlag KG, 2017. http://dx.doi.org/10.1055/s-0037-1608274.
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Fadeeva, S., I. Goncharov, A. Litvinova, N. Oblasov, M. Veklich, V. Samoilenko y A. Zherdeva. "Aryl Isoprenoids of Paleozoic Oils of Southeastern Western Siberia (Russia)". En 30th International Meeting on Organic Geochemistry (IMOG 2021). European Association of Geoscientists & Engineers, 2021. http://dx.doi.org/10.3997/2214-4609.202134121.
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Öztoprak, M. "Investigating the Intramolecular Isotopic Structure of Isoprenoids Using Orbitrap Mass Spectrometry". En 30th International Meeting on Organic Geochemistry (IMOG 2021). European Association of Geoscientists & Engineers, 2021. http://dx.doi.org/10.3997/2214-4609.202134246.
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Lipko, Agata, Adam Jozwiak, Magdalena Kania, Witold Danikiewicz, Marta Hoffman-Sommer, Liliana Surmacz, Michel Rohmer, Jaroslaw Poznanski y Ewa Swiezewska. "Biochemical tools to monitor isoprenoid biosynthesis – the case of polyprenol and dolichol". En New frontiers in natural product chemistry, scientific seminar with international participation. Institute of Chemistry, 2021. http://dx.doi.org/10.19261/nfnpc.2021.ab04.
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Dickerson, Lindsy, Aditi Jain, Pamela L. Crowell, James C. K. Lai y Alok Bhushan. "Abstract 1930: Inhibition of glioblastoma cell growth with the isoprenoids perillyl alcohol, farnesol, and geraniol". En Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL. American Association for Cancer Research, 2012. http://dx.doi.org/10.1158/1538-7445.am2012-1930.
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Corcoran, Megan, Aaron Diefendorf, Thomas Lowell, Nicholas Wiesenberg, Gregory Wiles, Mark A. Wilson, Watts Dietrich y Justine Paul Berina. "SEASONALITY OF HYDROGEN ISOTOPES AND CONCENTRATIONS OF HIGHLY BRANCHED ISOPRENOIDS (HBIS) PRODUCED BY LAKE DIATOMS". En Joint 56th Annual North-Central/ 71st Annual Southeastern Section Meeting - 2022. Geological Society of America, 2022. http://dx.doi.org/10.1130/abs/2022nc-374532.
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Gies, H., D. Montlucon, N. Haghipour, M. Lupker, T. S. van der Voort, F. Hagedorn y T. I. Eglinton. "Radiocarbon Analysis of Isoprenoid and Branched Glycerol Dialkyl Glycerol Tetraethers in Soils and Fluvial Sediments". En 29th International Meeting on Organic Geochemistry. European Association of Geoscientists & Engineers, 2019. http://dx.doi.org/10.3997/2214-4609.201903045.
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Reilly, Jacqueline E., Jeffrey D. Neighbors, Nadine Bannick, Michael D. Henry, Craig H. Kuder y Raymond J. Hohl. "Abstract 4032: Targeting the isoprenoid biosynthetic pathway in a murine model of metastatic prostate cancer". En Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-4032.
Texto completoInformes sobre el tema "Isoprenoidi"
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Ginzberg, Idit, Richard E. Veilleux y James G. Tokuhisa. Identification and Allelic Variation of Genes Involved in the Potato Glycoalkaloid Biosynthetic Pathway. United States Department of Agriculture, agosto de 2012. http://dx.doi.org/10.32747/2012.7593386.bard.
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Steroidal glycoalkaloids (SGAs) are secondary metabolites being part of the plant defense response. The two major SGAs in cultivated potato (Solanum tuberosum) are α-chaconine and α-solanine, which exhibit strong cellular lytic properties and inhibit acetylcholinesterase activity, and are poisonous at high concentrations for humans. As SGAs are not destroyed during cooking and frying commercial cultivars have been bred to contain low levels, and their content in tubers should not exceed 20 mg/100 g fresh weight. However, environmental factors can increase tuber SGA content above the safe level. The focus of the proposed research was to apply genomic approaches to identify candidate genes that control potato SGA content in order to develop tools for potato improvement by marker-assisted selection and/or transgenic approaches. To this end, the objectives of the proposal included identification of genes, metabolic intermediates and allelic variations in the potato SGAbiosynthetic pathway. The SGAs are biosynthesized by the sterol branch of the mevalonic acid/isoprenoid pathway. Transgenic potato plants that overexpress 3-hydroxy-3-methylglutaryl-CoA reductase 1 (HMG1) or squalene synthase 1 (SQS1), key enzymes of the mevalonic acid/isoprenoid pathway, exhibited elevated levels of solanine and chaconine as well as induced expression of genes downstream the pathway. These results suggest of coordinated regulation of isoprenoid (primary) metabolism and SGA secondary metabolism. The transgenic plants were further used to identify new SGA-related candidate genes by cDNA-AFLP approach and a novel glycosyltransferase was isolated. In addition, genes involved in phytosterol biosynthesis may have dual role and synthesize defense-related steroidal metabolites, such as SGAs, via lanosterol pathway. Potato lanosterol synthase sequence (LAS) was isolated and used to prepare transgenic plants with overexpressing and silencing constructs. Plants are currently being analyzed for SGA content. The dynamics of SGA accumulation in the various organs of a potato species with high SGA content gave insights into the general regulation of SGA abundance. Leaf SGA levels in S. chacoense were 10 to 20-fold greater than those of S. tuberosum. The leptines, SGAs with strong antifeedant properties against Colorado potato beetles, were present in all aerial tissues except for early and mid-developmental stages of above ground stolons, and accounted for the high SGA content of S. chacoense. These results indicate the presence of regulatory mechanisms in most tissues except in stolons that limit the levels of α-solanine and α-chaconine and confine leptine accumulation to the aerial tissues. The genomes of cultivated and wild potato contain a 4-member gene family coding for SQS. Three orthologs were cloned as cDNAs from S. chacoense and heterologously expressed in E. coli. Squalene accumulated in all E. coli lines transformed with each of the three gene constructs. Differential transcript abundance in various organs and amino acid sequence differences in the conserved domains of three isoenzymes indicate subfunctionalization of SQS activity and triterpene/sterol metabolism. Because S. chacoense and S. phureja differ so greatly for presence and accumulation of SGAs, we selected four candidate genes from different points along the biosynthetic pathway to determine if chcor phuspecific alleles were associated with SGA expression in a segregating interspecific diploid population. For two of the four genes (HMG2 and SGT2) F2 plants with chcalleles expressed significantly greater total SGAs compared with heterozygotes and those with phualleles. Although there are other determinants of SGA biosynthesis and composition in potato, the ability of allelic states at two genes to affect SGA levels confirms some of the above transgenic work where chcalleles at two other loci altered SGA expression in Desiree. Present results reveal new opportunities to manipulate triterpene/sterol biosynthesis in more targeted ways with the objective of altering SGA content for both human health concerns and natural pesticide content without disrupting the essential metabolism and function of the phytosterol component of the membranes and the growth regulating brassinosteroids.
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Yalovsky, Shaul y Julian Schroeder. The function of protein farnesylation in early events of ABA signal transduction in stomatal guard cells of Arabidopsis. United States Department of Agriculture, enero de 2002. http://dx.doi.org/10.32747/2002.7695873.bard.
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Loss of function mutations in the farnesyltransferase β subunit gene ERA1 (enhanced response to abscisic acid), cause abscisic acid hypersensitivity in seedlings and in guard cells. This results in slowed water loss of plants in response to drought. Farnesyltransferase (PFT) catalyses the attachment of the 15-carbon isoprenoid farnesyl to conserved cysteine residues located in a conserved C-terminal domain designated CaaX box. PFT is a heterodimeric protein comprised of an a and b sununits. The a subunit is shared between PFT and geranylgeranyltransferase-I (PGGTI) which catalyses the attachemt of the 20-carbon isoprenoid geranylgeranyl to CaaX box proteins in which the last amino acid is almost always leucine and in addition have a polybasic domain proximal to the CaaL box. Preliminary data presented in the proposal showed that increased cytoplasmic Ca2+ concentration in stomal guard cells in response to non-inductive ABA treatements. The goals set in the proposal were to characterize better how PFT (ERA1) affects ABA induced Ca2+ concentrations in guard cells and to identify putative CaaX box proteins which function as negative regulators of ABA signaling and which function is compromised in era1 mutant plants. To achieve these goals we proposed to use camelion Ca2+ sensor protein, high throughput genomic to identify the guard cell transcriptome and test prenylation of candidate proteins. We also proposed to focus our efforts of RAC small GTPases which are prenylated proteins which function in signaling. Our results show that farnesyltransferaseprenylates protein/s that act between the points of ABA perception and the activation of plasma membrane calcium influx channels. A RAC protein designated AtRAC8/AtRop10 also acts in negative regulation of ABA signaling. However, we discovered that this protein is palmitoylated and not prenylated although it contains a C-terminal CXXX motif. We further discovered a unique C-terminal sequence motif required for membrane targeting of palmitoylatedRACs and showed that their function is prenylation independent. A GC/MS based method for expression in plants, purification and analysis of prenyl group was developed. This method would allow highly reliable identification of prenylated protein. Mutants in the shared α subunit of PFT and PGGT-I was identified and characterized and was shown to be ABA hypersensitive but less than era1. This suggested that PFT and PGGT-I have opposing functions in ABA signaling. Our results enhanced the understanding of the role of protein prenylation in ABA signaling and drought resistance in plants with the implications of developing drought resistant plants. The results of our studies were published 4 papers which acknowledge support from BARD.
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Total organic carbon, extractable organic matter, rock-eval parameters, isoprenoid ratios, carbon preference index, and isotopic data from cuttings of the AMOCO Cathedral River #1 well. Alaska Division of Geological & Geophysical Surveys, 1986. http://dx.doi.org/10.14509/19199.
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