RESUMEN

The mating hormones α1 and α2 induce sexual reproduction of the phytopathogenic genus Phytophthora. To demonstrate the structural elements responsible to hormonal activity, 17 derivatives of α1 and α2 were synthesized and their hormonal activity (oospore-inducing activity) was evaluated. The terminal ester derivatives of α1 (diacetate and dibenzoate) retained the hormonal activity, whereas a dicarbamate derivative completely suppressed the activity. Even monocarbamates showed weak activities; among them the 1-O-carbamate was less active than 16-O-carbamate, suggesting that the 1-OH group is a little more important than 16-OH. Dihydro, dehydro, and demethyl derivatives exhibited the minimum level of activity. Surviving activity of 15-epi-α1 suggested a less importance of this stereochemistry. Contrary to α1, not only the terminal diacetate derivative but also monoacetates of α2 exhibited no or little activity. Among the monoacetates, 1-O-acetyl-α2 exhibited little yet relatively better activity than the others. No activity was observed for mono- and dicarbamoyl derivatives of α2. Dihydro α2 with the saturated double bond lost most of the activity. These findings suggest that both the mating hormones α1 and α2 require most of the functional (hydroxyl, keto, and olefinic) groups they possess in their natural form for inducing the sexual reproduction of Phytophthora.

Asunto(s)

Diterpenos/química , Phytophthora/metabolismo , Carbamatos/química , Diterpenos/síntesis química , Diterpenos/farmacología , Phytophthora/efectos de los fármacos , Estereoisomerismo , Relación Estructura-Actividad

RESUMEN

Four stereoisomers of roseoside (vomifoliol glucosides) were synthesized using glucose as a chiral resolving reagent. The four synthetic stereoisomers exhibited inhibitory activity on leukotriene release from mouse bone marrow-derived cultured mast cells (BMCMC). The (6S)-isomers of roseoside were about twice as active as (6R)-isomers.

Asunto(s)

Glucósidos/síntesis química , Leucotrienos/metabolismo , Norisoprenoides/síntesis química , Animales , Médula Ósea , Glucosa , Glucósidos/farmacología , Mastocitos , Ratones , Norisoprenoides/farmacología , Estereoisomerismo , Relación Estructura-Actividad

RESUMEN

The four stereoisomers of small bacteriocin, an autoinducer of the symbiotic nitrogen-fixing bacterium Rhizobium leguminosarum, were synthesized via a versatile methodology for 3'-hydroxyacyl homoserine lactones based on the Nagao asymmetric aldol reaction. The synthetic isomers were much less effective at inhibiting the growth of R. leguminosarum RBL5523 than the natural isomer, showing the importance of stereochemistry for activity.

Asunto(s)

4-Butirolactona/análogos & derivados , Bacteriocinas/química , Bacteriocinas/síntesis química , Nitrógeno/química , Rhizobium leguminosarum/química , 4-Butirolactona/síntesis química , 4-Butirolactona/química , 4-Butirolactona/farmacología , Bacteriocinas/farmacología , Pruebas de Sensibilidad Microbiana , Estructura Molecular , Rhizobium leguminosarum/efectos de los fármacos , Estereoisomerismo

RESUMEN

An important biological event in phytopathogens of the genus Phytophthora is sexual reproduction, which is conducted by two mating types, A1 and A2. A factor known as hormone alpha1 is secreted by the A1 mating type and induces the formation of sexual spores (oospores) in the A2 mating type. Here we describe the asymmetric synthesis and assignment of the absolute configuration of hormone alpha1 by oospore-inducing assays of the synthesized isomers.

Asunto(s)

Diterpenos/química , Diterpenos/síntesis química , Proteínas Fúngicas/química , Proteínas Fúngicas/síntesis química , Phytophthora/química , Espectroscopía de Resonancia Magnética/métodos , Conformación Molecular , Tamaño de la Partícula , Estereoisomerismo

RESUMEN

An asymmetric total synthesis of ent-sandaracopimaradiene, a biosynthetic intermediate of oryzalexins, via B-alkyl Suzuki-Miyaura coupling and Lewis acid-mediated B-ring formation as key steps was achieved.

Asunto(s)

Diterpenos/síntesis química , Terpenos/síntesis química , Sesquiterpenos , Estereoisomerismo , Fitoalexinas

RESUMEN

An efficient and stereoselective synthesis of three stereoisomers of the sex pheromone of the cowpea weevil, Callosobruchus maculatus, is reported.

Asunto(s)

Ácidos Carboxílicos/síntesis química , Atractivos Sexuales/síntesis química , Gorgojos/metabolismo , Monoterpenos Acíclicos , Animales , Ácidos Carboxílicos/química , Ácidos Dicarboxílicos/síntesis química , Ácidos Dicarboxílicos/química , Atractivos Sexuales/química , Estereoisomerismo

RESUMEN

The stereoisomeric composition of the copulation release pheromone of the azuki bean weevil, Callosobruchus chinensis L., was determined to be R:S=3.3-3.4:1 by the 2D-Ohrui-Akasaka method.

Asunto(s)

Copulación , Atractivos Sexuales/química , Conducta Sexual Animal , Gorgojos/fisiología , Animales , Cromatografía Líquida de Alta Presión , Espectrometría de Fluorescencia , Estereoisomerismo

RESUMEN

A diastereomeric mixture and the four stereoisomers of 2,6-dimethyloctane-1,8-dioic acid (2), a copulation release pheromone of the cowpea weevil, Callosobruchus maculatus, were synthesized. The stereoisomeric purities of the four synthetic isomers of 2 were determined by the HPLC analyses of their bis-2-(2,3-anthracenedicarboximide)-1-cyclohexyl esters.

Asunto(s)

Ácidos Dicarboxílicos/síntesis química , Atractivos Sexuales/síntesis química , Gorgojos/química , Monoterpenos Acíclicos , Cromatografía Líquida de Alta Presión , Ácidos Dicarboxílicos/química , Indicadores y Reactivos , Espectroscopía de Resonancia Magnética , Conformación Molecular , Oxidación-Reducción , Atractivos Sexuales/química , Espectrofotometría Infrarroja , Estereoisomerismo , Relación Estructura-Actividad

RESUMEN

We have isolated and characterized a cDNA encoding a novel diterpene cyclase, OsDTC1, from suspension-cultured rice cells treated with a chitin elicitor. OsDTC1 functions as ent-cassa-12,15-diene synthase, which is considered to play a key role in the biosynthesis of (-)-phytocassanes recently isolated as rice diterpenoid phytoalexins. The expression of OsDTC1 mRNA was also confirmed in ultraviolet (UV)-irradiated rice leaves. In addition, we identified ent-cassa-12,15-diene, a putative diterpene hydrocarbon precursor of (-)-phytocassanes, as an endogenous compound in the chitin-elicited suspension-cultured rice cells and the UV-irradiated rice leaves. The OsDTC1 cDNA isolated here will be a useful tool to investigate the regulatory mechanisms of the biosynthesis of (-)-phytocassanes in rice.

Asunto(s)

Diterpenos/metabolismo , Isomerasas/genética , Oligosacáridos/farmacología , Oryza/genética , Extractos Vegetales/biosíntesis , Proteínas de Plantas/genética , Secuencia de Aminoácidos , Células Cultivadas , Quitina/análogos & derivados , Quitina/farmacología , Clonación Molecular , ADN Complementario/química , ADN Complementario/genética , Escherichia coli/genética , Escherichia coli/metabolismo , Regulación Enzimológica de la Expresión Génica , Regulación de la Expresión Génica de las Plantas , Isomerasas/metabolismo , Datos de Secuencia Molecular , Oryza/enzimología , Oryza/metabolismo , Hojas de la Planta/enzimología , Hojas de la Planta/genética , Hojas de la Planta/efectos de la radiación , Proteínas de Plantas/metabolismo , ARN Mensajero/genética , ARN Mensajero/metabolismo , Análisis de Secuencia de ADN , Homología de Secuencia de Aminoácido , Sesquiterpenos , Terpenos , Rayos Ultravioleta , Fitoalexinas