RESUMEN
Germacrene A, the elusive biogenetic "parent" of many sesquiterpenes, has been isolated from the spotted alfalfa aphid and identified as a new intrageneric aphid alarm pheromone.
Asunto(s)
Áfidos/fisiología , Miedo/fisiología , Feromonas , Sesquiterpenos , Animales , Áfidos/análisis , Espectroscopía de Resonancia Magnética , Feromonas/aislamiento & purificación , Feromonas/fisiología , Sesquiterpenos/aislamiento & purificación , Espectrofotometría InfrarrojaAsunto(s)
Áfidos/análisis , Triglicéridos/análisis , Animales , Femenino , Masculino , Estaciones del AñoRESUMEN
The nucleotide sequence of 5S rRNA from the elder aphid. Acyrthosiphon magnoliae was determined by using postlabeling sequencing techniques. The aphid 5S rRNA consists of 120 nucleotides and the sequence differs from those of Bombyx and Drosophila 5S rRNAs in 14 and 16 positions, respectively. A secondary structure model based on the sequence has two distinctive features : the helix I is shorter and the total free energy lower. Judging from the thermal profile, the aphid 5S rRNA likely assumes a conformation somewhat different from those of the other two insects.
Asunto(s)
Áfidos/análisis , ARN Ribosómico , Animales , Secuencia de Bases , Bombyx/análisis , Drosophila melanogaster/análisis , Peso Molecular , Conformación de Ácido Nucleico , Desnaturalización de Ácido Nucleico , Especificidad de la Especie , TemperaturaRESUMEN
If RNA is extracted from the ribosomes which had been isolated from frozen-thawed tissue of Galleria mellonella, the 28 S RNA, when heated or treated with urea, dissociates into seven different species of polynucleotide fragments. They were designated as R1, R2, R3, R4, R5, R6, and R7, whose molecular weights were estimated to be 1.15x10-6, 0.75x10-6, 0.55x10-6, 0.40x10-6, 0.30x10-6, 0.25x10-6, 0.20x10-6 daltons, respectively. It is likely that R1 and R5 arise from a single nick in original 38 S rRNA. Experiments with isolated R1 suggest that it is made up of a hydrogen-bonded complex of R2 and R4. R5 is a complex of R6 and an unidentified species, X. It is suggested that these fragments result from nicks which are introduced, secondarily, in the phosphodiester bonds by an endogenous endonuclease(s). Since the secondary nicks are limited in number and located in specific points of the molecule, it appears that the reaction is quite specific. It was also shown that the 28 S aphid RNA, which apparently lacks the primary nick, is susceptible to nicking.