RESUMO
Wehave identified, cloned, and characterized two odorant binding proteins from the pale brown chafer, Phyllopertha diversa. One of the proteins (OBP1, 116 amino acids long) showed high amino acid identity (>90%) to two previously identified PBPs from scarab beetles. The second protein (OBP2) showed limited sequence similarity to lepidopteran and dipteran OBPs, but contained only 133 amino acids. Both proteins showed the occurrence of six highly conserved cysteines; electrospray mass spectral data suggested they are all bound in three disulfide bonds. During purification, OBP2 separated into several isoforms; N-terminal amino acid sequencing and electrospray ionization mass spectrometry demonstrated that they are different conformations of the same protein. In the native gel electrophoresis binding experiments, none of the OBPs bound 1, 3-dimethyl-2,4-(1H,3H)-quinazolinedione but different isoforms showed different binding affinities for (R)-japonilure, a pheromone from related scarab beetles, and bombykol, the pheromone from the silkworm moth, Bombyx mori. OBP1 also bound (R)-japonilure.
Assuntos
Besouros/fisiologia , Odorantes , Receptores Odorantes/química , Receptores Odorantes/genética , Sequência de Aminoácidos , Animais , Clonagem Molecular , Besouros/genética , Dados de Sequência Molecular , Peso Molecular , Receptores Odorantes/isolamento & purificação , Proteínas Recombinantes/biossíntese , Proteínas Recombinantes/isolamento & purificação , Alinhamento de Sequência , Homologia de Sequência de AminoácidosRESUMO
Four compounds have been identified as sex pheromone constituents of the scarab beetleAnomala albopilosa albopilosa, namely (R, Z)-5-(-)-(oct-1-enyl)oxacyclopentan-2-one (buibuilactone), 2-(E)-nonenol, 2-(E)-nonenal, and methyl benzoate (in the ratio 10:3:3:1). The diel rhythm of pheromone release inA. a. albopilosa showed a peak at the beginning of the scotophase, which is also a peak of mating activity. On the other hand, the similar speciesA. cuprea utilizes a two-constituent sex pheromone, having a common major component, but the pheromone is released both during scoto-and photophase. Temporal difference in mating activity and pheromone release along with chemical diversity seem to form the basis for maintaining species specificity in pheromonal communication betweenA. a. albopilosa andA. cuprea.
RESUMO
The alarm pheromone system ofLeptoglossus zonatus (Dallas) adults was shown to be composed of hexyl acetate, hexanol, hexanal, and hexanoic acid. Single components tested in the field elicited dispersive behavior of over 70% of adults. 2-(E)-Hexenal, found in the secretion of nymphs, but not in the exudates of adults, was also active against adults. In addition, first-instar nymphs responded to the four components of the alarm pheromone of adults as well as to 2-(E)-hexenal, a component of their own alarm pheromone system. Adults and nymphs possess different alarm pheromone systems, which are not specific to their own life stage. That hemipteran alarm pheromone systems are not species-specific was supported by the fact that both adult and nymphL. zonatus responded to butanoic acid, an alarm pheromone of Alydidae, which was not found in this Coreidae species.