RESUMEN
Animals increase their feeding motivation under starved conditions. Here the authors test if the starvation-induced increase of feeding motivation is different among wild-derived strains of Drosophila melanogaster. In behavioral experiments comparing the feeding behaviors of the strains Mel6 and TW1, only TW1 exhibited a decreased feeding threshold to sucrose following a 24-h starvation period. Starved TW1 preferably ingested a low concentration of sucrose. Starved TW1 also exhibited significant elevation of taste responsiveness to low concentrations of sucrose and enhanced expression of the Gr64a sucrose sugar receptor gene. TW1 survived longer than Mel6 when provided a less nutritious food (10 mM sucrose). Thus, the starvation-induced decrease in the behavioral and the sensory thresholds could be an advantage in searching for and utilizing less nutritious foods. These results show that the starvation-induced functional change in the taste sensory system is a possible strategy for survival during starvation or suboptimal nutrient periods.
Asunto(s)
Proteínas de Drosophila/metabolismo , Drosophila melanogaster/fisiología , Preferencias Alimentarias/fisiología , Regulación de la Expresión Génica/fisiología , Receptores de Superficie Celular/metabolismo , Inanición/fisiopatología , Animales , Conducta Animal , Carbohidratos/farmacología , Relación Dosis-Respuesta a Droga , Proteínas de Drosophila/genética , Proteínas de Drosophila/fisiología , Drosophila melanogaster/genética , Conducta Alimentaria/efectos de los fármacos , Conducta Alimentaria/fisiología , Femenino , Preferencias Alimentarias/efectos de los fármacos , Regulación de la Expresión Génica/efectos de los fármacos , ARN Mensajero/metabolismo , Receptores de Superficie Celular/genética , Células Receptoras Sensoriales/efectos de los fármacos , Células Receptoras Sensoriales/fisiología , Especificidad de la Especie , Inanición/mortalidad , Sacarosa/administración & dosificación , Azúcares Ácidos , Análisis de Supervivencia , Edulcorantes/administración & dosificaciónRESUMEN
[reaction: see text] The intermolecular alkyl radical addition to imine derivatives was studied in aqueous media by using indium as a single-electron-transfer radical initiator. The one-pot reaction based on radical addition to glyoxylic hydrazone provided a convenient method for preparing the alpha-amino acids. The indium-mediated radical addition to an electron-deficient C=C bond also proceeded effectively to provide the new carbon-carbon bond-forming method in aqueous media.
RESUMEN
[reaction: see text] Tandem carbon-carbon bond-forming reactions were studied by using indium as a single-electron-transfer radical initiator. The radical addition-cyclization-trap reaction of a substrate having a vinyl sulfonamide group and an olefin moiety proceeded smoothly in aqueous media. The radical addition-cyclization reaction of hydrazone gave the functionalized cyclic products.
RESUMEN
The indium-mediated allylation and alkylation reactions of the Oppolzer camphorsultam derivative of glyoxylic oxime ether proceeded with excellent diastereoselectivity in aqueous media, providing a variety of enantiomerically pure alpha-amino acids.
RESUMEN
Starvation is a common experience under fluctuating food conditions in nature, and response to it is vital for many organisms. Many studies have investigated the response at physiological and behavioral level, whereas the studies on starvation-induced transcriptional changes in the brain and the surrounding tissues are still limited. We here investigated global changes in transcript abundance in the head after 24 h starvation by microarray expression profiling of 2 wild-derived inbred strains of Drosophila melanogaster, and identified a core set of 65 up-regulated and 48 down-regulated genes upon starvation. Among these up-regulated genes, 22 genes were circadian oscillating genes previously identified in the head of Drosophila. Interestingly, most (86%) of these circadian genes show their expression peak in a narrow time range of ZT7.0-12.0, when flies are relatively restless and less feeding in the normal condition. Among the down-regulated genes, 2 genes with highest fold-differences, fit and CG8147, are known to have female-biased expression in the head, and 1 gene, Obp99b, is known to be male-biased. Together with the realtime qPCR experiments on female and male transcripts, our data suggest that these sex-specific genes are candidate genes mediating a possible trade-off between starvation resistance and reproduction. Eleven down-regulated genes are known to be involved in the immune response. These changes in head transcriptome upon starvation reflect modulation of expression in some normally oscillating rhythmic genes and reduction in the resource allocation toward sexual activity and immunity.
Asunto(s)
Drosophila melanogaster/genética , Genes de Insecto , Inanición/genética , Animales , Ritmo Circadiano/genética , Regulación hacia Abajo , Drosophila melanogaster/fisiología , Femenino , Perfilación de la Expresión Génica , Cabeza , Masculino , ARN Mensajero/genética , ARN Mensajero/metabolismo , Reproducción/genética , Caracteres Sexuales , Especificidad de la Especie , Regulación hacia ArribaRESUMEN
The novel tandem radical addition-cyclization of oxime ethers and hydrazones intramolecularly connected with the alpha,beta-unsaturated carbonyl group is described. The radical reaction of oxime ethers 1, 2, and 4 connected with acryloyl and methacryloyl moieties proceeded smoothly to give the heterocycles via a tandem C-C bond-forming process. The tandem reaction of hydrazone 5 took place in the presence of Zn(OTf)(2) as a Lewis acid to give the trans-cyclic product 17 without the formation of the cis-isomer. The diastereoselective radical addition-cyclization reaction of chiral oxime ether 19 was also studied. The tandem reaction of 19 proceeded smoothly even in aqueous media, providing the novel method for asymmetric synthesis of gamma-butyrolactones and beta-amino acid derivatives.