RESUMO
The presence of arsenic in soil and water is a constant threat to plant growth in many regions of the world. Phytohormones act in the integration of growth control and stress response, but their role in plant responses to arsenic remains to be elucidated. Here, we show that arsenate [As(V)], the most prevalent arsenic chemical species in nature, causes severe depletion of endogenous cytokinins (CKs) in the model plant Arabidopsis (Arabidopsis thaliana). We found that CK signaling mutants and transgenic plants with reduced endogenous CK levels showed an As(V)-tolerant phenotype. Our data indicate that in CK-depleted plants exposed to As(V), transcript levels of As(V)/phosphate-transporters were similar or even higher than in wild-type plants. In contrast, CK depletion provoked the coordinated activation of As(V) tolerance mechanisms, leading to the accumulation of thiol compounds such as phytochelatins and glutathione, which are essential for arsenic sequestration. Transgenic CK-deficient Arabidopsis and tobacco lines show a marked increase in arsenic accumulation. Our findings indicate that CK is an important regulatory factor in plant adaptation to arsenic stress.
Assuntos
Adaptação Fisiológica/efeitos dos fármacos , Arsênio/metabolismo , Arsênio/toxicidade , Citocininas/farmacologia , Compostos de Sulfidrila/metabolismo , Butionina Sulfoximina/farmacologia , Regulação para Baixo/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Glutationa/metabolismo , Inativação Metabólica/efeitos dos fármacos , Fenótipo , Fitoquelatinas/metabolismo , Regulação para Cima/efeitos dos fármacosRESUMO
To cope with growth in low-phosphate (Pi) soils, plants have evolved adaptive responses that involve both developmental and metabolic changes. Phosphate Starvation Response 1 (PHR1) and related transcription factors play a central role in the control of Pi starvation responses (PSRs). How Pi levels control PHR1 activity, and thus PSRs, remains to be elucidated. Here, we identify a direct Pi-dependent inhibitor of PHR1 in Arabidopsis, SPX1, a nuclear protein that shares the SPX domain with yeast Pi sensors and with several Pi starvation signaling proteins from plants. Double mutation of SPX1 and of a related gene, SPX2, resulted in molecular and physiological changes indicative of increased PHR1 activity in plants grown in Pi-sufficient conditions or after Pi refeeding of Pi-starved plants but had only a limited effect on PHR1 activity in Pi-starved plants. These data indicate that SPX1 and SPX2 have a cellular Pi-dependent inhibitory effect on PHR1. Coimmunoprecipitation assays showed that the SPX1/PHR1 interaction in planta is highly Pi-dependent. DNA-binding and pull-down assays with bacterially expressed, affinity-purified tagged SPX1 and ΔPHR1 proteins showed that SPX1 is a competitive inhibitor of PHR1 binding to its recognition sequence, and that its efficiency is highly dependent on the presence of Pi or phosphite, a nonmetabolizable Pi analog that can repress PSRs. The relative strength of the SPX1/PHR1 interaction is thus directly influenced by Pi, providing a link between Pi perception and signaling.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/metabolismo , Proteínas Nucleares/metabolismo , Fosfatos/farmacologia , Fatores de Transcrição/metabolismo , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/antagonistas & inibidores , Proteínas de Arabidopsis/genética , DNA de Plantas/metabolismo , Modelos Biológicos , Mutação/genética , Proteínas Nucleares/genética , Ligação Proteica/efeitos dos fármacos , Fatores de Transcrição/antagonistas & inibidoresRESUMO
Stress constantly challenges plant adaptation to the environment. Of all stress types, arsenic was a major threat during the early evolution of plants. The most prevalent chemical form of arsenic is arsenate, whose similarity to phosphate renders it easily incorporated into cells via the phosphate transporters. Here, we found that arsenate stress provokes a notable transposon burst in plants, in coordination with arsenate/phosphate transporter repression, which immediately restricts arsenate uptake. This repression was accompanied by delocalization of the phosphate transporter from the plasma membrane. When arsenate was removed, the system rapidly restored transcriptional expression and membrane localization of the transporter. We identify WRKY6 as an arsenate-responsive transcription factor that mediates arsenate/phosphate transporter gene expression and restricts arsenate-induced transposon activation. Plants therefore have a dual WRKY-dependent signaling mechanism that modulates arsenate uptake and transposon expression, providing a coordinated strategy for arsenate tolerance and transposon gene silencing.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Arseniatos/metabolismo , Elementos de DNA Transponíveis/genética , Fatores de Transcrição/metabolismo , Arabidopsis/efeitos dos fármacos , Arseniatos/toxicidade , Sequência de Bases , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Regulação para Baixo/efeitos dos fármacos , Histonas/metabolismo , Lisina/metabolismo , Dados de Sequência Molecular , Fenótipo , Proteínas de Transporte de Fosfato/metabolismo , Fosfatos/metabolismo , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Proteínas Repressoras/metabolismoRESUMO
MicroRNAs (miRNA) regulate key aspects of development and physiology in animals and plants. These regulatory RNAs act as guides of effector complexes to recognize specific mRNA sequences based on sequence complementarity, resulting in translational repression or site-specific cleavage. In plants, most miRNA targets are cleaved and show almost perfect complementarity with the miRNAs around the cleavage site. Here, we examined the non-protein coding gene IPS1 (INDUCED BY PHOSPHATE STARVATION 1) from Arabidopsis thaliana. IPS1 contains a motif with sequence complementarity to the phosphate (Pi) starvation-induced miRNA miR-399, but the pairing is interrupted by a mismatched loop at the expected miRNA cleavage site. We show that IPS1 RNA is not cleaved but instead sequesters miR-399. Thus, IPS1 overexpression results in increased accumulation of the miR-399 target PHO2 mRNA and, concomitantly, in reduced shoot Pi content. Engineering of IPS1 to be cleavable abolishes its inhibitory activity on miR-399. We coin the term 'target mimicry' to define this mechanism of inhibition of miRNA activity. Target mimicry can be generalized beyond the control of Pi homeostasis, as demonstrated using artificial target mimics.
Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas , MicroRNAs/metabolismo , Proteínas de Plantas/genética , RNA de Plantas/metabolismo , Enzimas de Conjugação de Ubiquitina/genética , Arabidopsis/metabolismo , Mimetismo Molecular , Dados de Sequência Molecular , Proteínas de Plantas/metabolismoRESUMO
Plants respond to different stresses by inducing or repressing transcription of partially overlapping sets of genes. In Arabidopsis, the PHR1 transcription factor (TF) has an important role in the control of phosphate (Pi) starvation stress responses. Using transcriptomic analysis of Pi starvation in phr1, and phr1 phr1-like (phl1) mutants and in wild type plants, we show that PHR1 in conjunction with PHL1 controls most transcriptional activation and repression responses to phosphate starvation, regardless of the Pi starvation specificity of these responses. Induced genes are enriched in PHR1 binding sequences (P1BS) in their promoters, whereas repressed genes do not show such enrichment, suggesting that PHR1(-like) control of transcriptional repression responses is indirect. In agreement with this, transcriptomic analysis of a transgenic plant expressing PHR1 fused to the hormone ligand domain of the glucocorticoid receptor showed that PHR1 direct targets (i.e., displaying altered expression after GR:PHR1 activation by dexamethasone in the presence of cycloheximide) corresponded largely to Pi starvation-induced genes that are highly enriched in P1BS. A minimal promoter containing a multimerised P1BS recapitulates Pi starvation-specific responsiveness. Likewise, mutation of P1BS in the promoter of two Pi starvation-responsive genes impaired their responsiveness to Pi starvation, but not to other stress types. Phylogenetic footprinting confirmed the importance of P1BS and PHR1 in Pi starvation responsiveness and indicated that P1BS acts in concert with other cis motifs. All together, our data show that PHR1 and PHL1 are partially redundant TF acting as central integrators of Pi starvation responses, both specific and generic. In addition, they indicate that transcriptional repression responses are an integral part of adaptive responses to stress.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Fosfatos/deficiência , Proteínas Repressoras/metabolismo , Fatores de Transcrição/metabolismo , Ativação Transcricional/genética , Arabidopsis/efeitos dos fármacos , Proteínas de Arabidopsis/genética , Sequência de Bases , Sítios de Ligação , Pegada de DNA , Análise Mutacional de DNA , DNA de Plantas/metabolismo , Perfilação da Expressão Gênica , Genes de Plantas/genética , Dados de Sequência Molecular , Fosfatos/farmacologia , Filogenia , Plantas Geneticamente Modificadas , Regiões Promotoras Genéticas/genética , Ligação Proteica/efeitos dos fármacos , Multimerização Proteica/efeitos dos fármacos , Proteínas Repressoras/genética , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Fatores de Transcrição/genética , Transcrição Gênica/efeitos dos fármacos , Ativação Transcricional/efeitos dos fármacosRESUMO
Arsenic is one of the most potent carcinogens in the biosphere, jeopardizing the health of millions of people due to its entrance into the human food chain through arsenic-contaminated waters and staple crops, particularly rice. Although the mechanisms of arsenic sensing are widely known in yeast and bacteria, scientific evidence concerning arsenic sensors or components of early arsenic signaling in plants is still in its infancy. However, in recent years, we have gained understanding of the mechanisms involved in arsenic uptake and detoxification in different plant species and started to get insights into arsenic perception and signaling, which allows us to glimpse the possibility to design effective strategies to prevent arsenic accumulation in edible crops or to increase plant arsenic extraction for phytoremediation purposes. In this context, it has been recently described a mechanism according to which arsenite, the reduced form of arsenic, regulates the arsenate/phosphate transporter, consistent with the idea that arsenite functions as a selective signal that coordinates arsenate uptake with detoxification mechanisms. Additionally, several transcriptional and post-translational regulators, miRNAs and phytohormones involved in arsenic signaling and tolerance have been identified. On the other hand, studies concerning the developmental programs triggered to adapt root architecture in order to cope with arsenic toxicity are just starting to be disclosed. In this review, we compile and analyze the latest advances toward understanding how plants perceive arsenic and coordinate its acquisition with detoxification mechanisms and root developmental programs.
RESUMO
Phosphorus (P) is an essential nutrient for plant growth and reproduction. Plants preferentially absorb P as orthophosphate (Pi), an ion that displays low solubility and that is readily fixed in the soil, making P limitation a condition common to many soils and Pi fertilization an inefficient practice. To cope with Pi limitation, plants have evolved a series of developmental and physiological responses, collectively known as the Pi starvation rescue system (PSR), aimed to improve Pi acquisition and use efficiency (PUE) and protect from Pi-starvation-induced stress. Intensive research has been carried out during the last 20 years to unravel the mechanisms underlying the control of the PSR in plants. Here we review the results of this research effort that have led to the identification and characterization of several core Pi starvation signaling components, including sensors, transcription factors, microRNAs (miRNAs) and miRNA inhibitors, kinases, phosphatases, and components of the proteostasis machinery. We also refer to recent results revealing the existence of intricate signaling interplays between Pi and other nutrients and antagonists, N, Fe, Zn, and As, that have changed the initial single-nutrient-centric view to a more integrated view of nutrient homeostasis. Finally, we discuss advances toward improving PUE and future research priorities.
Assuntos
Adaptação Fisiológica/genética , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Fósforo/deficiência , Fósforo/metabolismo , Desenvolvimento Vegetal/efeitos dos fármacos , Reguladores de Crescimento de Plantas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Genes de Plantas , Desenvolvimento Vegetal/genética , Reguladores de Crescimento de Plantas/genéticaRESUMO
Cellular senescence is an antiproliferative response with a critical role in the control of cellular balance in diverse physiological and pathological settings. Here, we set to study the impact of senescence on the regulation of cell plasticity, focusing on the regulation of the myofibroblastic phenotype in primary fibroblasts. Myofibroblasts are contractile, highly fibrogenic cells with key roles in wound healing and fibrosis. Using cellular models of fibroblast senescence, we find a consistent loss of myofibroblastic markers and functional features upon senescence implementation. This phenotype can be transmitted in a paracrine manner, most likely through soluble secreted factors. A dynamic transcriptomic analysis during paracrine senescence confirmed the non-cell-autonomous transmission of this phenotype. Moreover, gene expression data combined with pharmacological and genetic manipulations of the major SASP signaling pathways suggest that the changes in myofibroblast phenotype are mainly mediated by the Notch/TGF-ß axis, involving a dynamic switch in the TGF-ß pathway. Our results reveal a novel link between senescence and myofibroblastic differentiation with potential implications in the physiological and pathological functions of myofibroblasts.
Assuntos
Senescência Celular , Miofibroblastos , Diferenciação Celular/fisiologia , Senescência Celular/genética , Fibroblastos/metabolismo , Miofibroblastos/metabolismo , Fenótipo , Fator de Crescimento Transformador beta/metabolismoRESUMO
In nature, plants acquire nutrients from soils to sustain growth, and at the same time, they need to avoid the uptake of toxic compounds and/or possess tolerance systems to cope with them. This is particularly challenging when the toxic compound and the nutrient are chemically similar, as in the case of phosphate and arsenate. In this study, we demonstrated that regulatory elements of the phosphate starvation response (PSR) coordinate the arsenate detoxification machinery in the cell. We showed that arsenate repression of the phosphate transporter PHT1;1 is associated with the degradation of the PSR master regulator PHR1. Once arsenic is sequestered into the vacuole, PHR1 stability is restored and PHT1;1 expression is recovered. Furthermore, we identified an arsenite responsive SKP1-like protein and a PHR1 interactor F-box (PHIF1) as constituents of the SCF complex responsible for PHR1 degradation.We found that arsenite, the form to which arsenate is reduced for compartmentalization in vacuoles, represses PHT1;1 expression, providing a highly selective signal versus phosphate to control PHT1;1 expression in response to arsenate. Collectively, our results provide molecular insights into a sensing mechanism that regulates arsenate/phosphate uptake depending on the plant's detoxification capacity.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arseniatos/metabolismo , Fatores de Transcrição/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Arseniatos/farmacologia , Transporte Biológico , Regulação da Expressão Gênica de Plantas , Proteínas de Transporte de Fosfato/genética , Proteínas de Transporte de Fosfato/metabolismo , Fosfatos/metabolismo , Plantas Geneticamente Modificadas , Fatores de Transcrição/genética , Vacúolos/metabolismoRESUMO
Hydration of a wide range of alkynes to the corresponding ketones has been afforded in high yields at room temperature by using gold(I)-phosphine complexes as catalyst, with no acidic cocatalysts required. Suitable substrates covering alkyl and aryl terminal alkynes, enynes, internal alkynes, and propargylic alcohols, including enantiopure forms, are cleanly transformed to the corresponding ketones in nearly quantitative yields. Acid-labile groups present in the substrates are preserved. The catalytic activity strongly depends on both the nature of the phosphine coordinated to the gold (I) center and the softness of the counteranion, the complex AuSPhosNTf(2) showing the better activity. A plausible mechanism for the hydration of alkynes through ketal intermediates is proposed on the basis of kinetic studies. The described catalytic system should provide an efficient alternative to mercury-based methodologies and be useful in synthetic programs.
Assuntos
Aldeídos/síntese química , Alcinos/química , Cetonas/síntese química , Compostos Organoáuricos/química , Temperatura , Aldeídos/química , Catálise , Cetonas/química , Ligantes , Estrutura Molecular , Estereoisomerismo , Água/químicaRESUMO
Plants have evolved numerous adaptive developmental and metabolic responses to cope with growth in conditions of limited phosphate (Pi). Regulation of these Pi starvation responses (PSR) at the organism level involves not only cellular Pi perception in different organs, but also inter-organ communication of Pi levels via systemic signaling. Here we summarize recent discoveries on Pi starvation sensing and signaling, with special emphasis on structure-function studies that showed a role for inositol polyphosphates (InsP) as intracellular Pi signals, and on genomic studies that identified a large number of mRNAs with inter-organ mobility, which provide an immense source of potential systemic signals in the control of PSR and other responses.
Assuntos
Fósforo/metabolismo , Plantas/metabolismo , Transdução de Sinais , Fosfatos de Inositol/metabolismoRESUMO
RESUMEN Fundamento: José Martí, Héroe Nacional de Cuba, consideraba que la medicina era como el derecho, profesión de lucha, y que se necesitaba un alma bien templada para desempeñar con éxito ese sacerdocio. Objetivo: diseñar un sistema de aplicaciones interactivas para segundo año de la carrera de Medicina con vistas a profundizar en la relación que tuvo José Martí con las ciencias médicas. Métodos: se realizó una investigación de desarrollo en el periodo septiembre-diciembre de 2018 en la Facultad de Ciencias Médicas de Bayamo, Cuba. Se utilizaron métodos teóricos y empíricos: revisión documental y cuestionario a estudiantes. Resultados: se confeccionó una herramienta efectiva para el conocimiento sobre José Martí y su relación con las ciencias médicas; antes de aplicar el sistema, la mayoría de los estudiantes del grupo control reflejaron un bajo nivel de conocimientos y poca motivación sobre esta temática; resultado que fue revertido después de aplicarlo, cuando la mayoría de los alumnos del grupo experimental alcanzó buenas calificaciones y se sintieron motivados por este tema. Conclusiones: el sistema de aplicaciones interactivas sobre los aspectos relacionados con José Martí y la medicina obtuvo valoraciones muy positivas por los expertos e influyó en el incremento del conocimiento y la motivación en los estudiantes, quienes mostraron una aceptación excelente por esta innovación tecnológica.
ABSTRACT Background: José Martí, National Hero of Cuba, considered that medicine was like law, a fighting profession, and that a well-tempered soul was needed to carry out this priesthood successfully. Objective: to design a system of interactive applications for the second year of Medicine with a view to deepening the relationship that José Martí had with medical sciences. Methods: a development research was carried out from September to December 2018 at the Faculty of Medical Sciences of Bayamo, Cuba. Theoretical and empirical methods were used: documentary review and student questionnaire. Results: an effective tool for knowledge about José Martí and his relationship with medical sciences was created; Before applying the system, most of the students in the control group reflected a low level of knowledge and little motivation on this subject; a result that was reversed after applying it, when most of the students in the experimental group achieved good grades and felt motivated by this topic. Conclusions: the system of interactive applications on aspects related to José Martí and medicine obtained very positive evaluations by the experts and influenced the increase of knowledge and motivation in the students, who showed an excellent acceptance for this technological innovation.
Assuntos
Estudantes de Medicina , Aplicações da Informática Médica , Projetos de Tecnologias de Informação e Comunicação , Educação MédicaRESUMO
An insoluble Merrifield type resin having 4-aminopyridine units is a suitable and reusable heterogeneous catalyst for the Baylis-Hillman coupling of aromatic aldehydes and alpha,beta-unsaturated ketones.
RESUMO
A preformed oxime-carbapalladacycle complex covalently anchored onto mercaptopropyl modified silica is highly active (> 99%) for the Suzuki reaction of p-chloroacetophenone and phenylboronic acid in water; no leaching occurs and the same catalyst sample was reused eight times without decreased activity.
RESUMO
The enormous amount of environmental arsenic was a major factor in determining the biochemistry of incipient life forms early in the Earth's history. The most abundant chemical form in the reducing atmosphere was arsenite, which forced organisms to evolve strategies to manage this chemical species. Following the great oxygenation event, arsenite oxidized to arsenate and the action of arsenate reductases became a central survival requirement. The identity of a biologically relevant arsenate reductase in plants nonetheless continues to be debated. Here we identify a quantitative trait locus that encodes a novel arsenate reductase critical for arsenic tolerance in plants. Functional analyses indicate that several non-additive polymorphisms affect protein structure and account for the natural variation in arsenate reductase activity in Arabidopsis thaliana accessions. This study shows that arsenate reductases are an essential component for natural plant variation in As(V) tolerance.
Assuntos
Proteínas de Arabidopsis/metabolismo , Arabidopsis/enzimologia , Arseniato Redutases/metabolismo , Arsênio/química , Regulação da Expressão Gênica de Plantas , Alelos , Sequência de Aminoácidos , Arabidopsis/efeitos dos fármacos , Arsenitos/química , Mapeamento Cromossômico , Escherichia coli/metabolismo , Teste de Complementação Genética , Modelos Moleculares , Conformação Molecular , Dados de Sequência Molecular , Mutação , Oxigênio/química , Fenótipo , Polimorfismo Genético , Locos de Características Quantitativas , Homologia de Sequência de Aminoácidos , Tiossulfato Sulfurtransferase/químicaRESUMO
Abstract The advanced GaAs:Cr material for radiation detection is in the scope of many scientific and technological institutions in the world, as a result of its proved superior properties and economic advantages. The energy calibration of a hybrid GaAs:Cr-based Timepix detector with alpha particles performed in the Dzhelepov Laboratory of Nuclear Problems at Joint Institute for Nuclear Research confirms that the device is able to register these particles in energy range from 3140 to 7687 keV. The mathematical simulation was used to calculate the transmitted energy, making possible the experimental calibration with the use of Mylar as absorbent. By calibrating the detector with characteristic X rays of some target materials and using a two steps fitting procedure was determined the relationship between the photon energies and the registered by the detector TOT counts. The energy calibration with alpha particles was performed according to a linear function and verified with the measurement of the 218Po line of radon in air.
Resumen El GaAs:Cr como material de avanzada para la detección de las radiaciones se encuentra en la mira de muchas instituciones científicas y tecnológicas en el mundo, como consecuencia de sus superiores propiedades y ventajas económicas. Los experimentos hechos en el Laboratorio de Problemas Nucleares Dzhelepov del Instituto Unificado de Investigaciones Nucleares para la calibración energética de un detector hibrido Timepix basado en GaAs:Cr con partículas alfa confirma que este dispositivo es capaz de registrar partículas en el rango energético de 3410 a 7687 keV. Se utilizó la simulación matemática para calcular la energía transmitida, haciendo posible la calibración experimental con el uso de Mylar como absorbente. Utilizando la calibración del detector hecha con los rayos X característicos de algunos materiales blanco y empleando un procedimiento de ajuste en dos pasos fue determinada la relación entre la energía de los fotones y los conteos TOT registrados por el detector. Se realizó la calibración energética con partículas alfa de acuerdo con una función lineal y se verificó con la medición de la línea del 218Po del radón en aire.
RESUMO
In plants, developmental programs and tropisms are modulated by the phytohormone auxin. Auxin reconfigures the actin cytoskeleton, which controls polar localization of auxin transporters such as PIN2 and thus determines cell-type-specific responses. In conjunction with a second growth-promoting phytohormone, brassinosteroid (BR), auxin synergistically enhances growth and gene transcription. We show that BR alters actin configuration and PIN2 localization in a manner similar to that of auxin. We describe a BR constitutive-response mutant that bears an allele of the ACTIN2 gene and shows altered actin configuration, PIN2 delocalization, and a broad array of phenotypes that recapitulate BR-treated plants. Moreover, we show that actin filament reconfiguration is sufficient to activate BR signaling, which leads to an enhanced auxin response. Our results demonstrate that the actin cytoskeleton functions as an integration node for the BR signaling pathway and auxin responsiveness.
Assuntos
Citoesqueleto de Actina/metabolismo , Brassinosteroides/metabolismo , Ácidos Indolacéticos/metabolismo , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica de Plantas , Mutação , Transdução de SinaisRESUMO
The first convergent total synthesis of isobongkrekic acid is reported involving three different stereospecific palladium cross-couplings for the formation of the diene units. Access to bongkrekic acid by this route is also demonstrated. These syntheses involve the formation of several potentially general building blocks.
Assuntos
Apoptose/efeitos dos fármacos , Ácido Bongcréquico/análogos & derivados , Ácido Bongcréquico/síntese química , Ácido Bongcréquico/farmacologia , Conformação Molecular , EstereoisomerismoRESUMO
Alkynes are preferentially hydroborated in the presence of alkenes when using gold catalysts; the active species involves a borane-gold interaction.