title: Unisex pheromone detectors and pheromone-binding proteins in scarab beetles.
abstract: Olfaction was studied in two species of scarab beetle, Anomala octiescostata and Anomala cuprea (Coleoptera: Scarabaeidae: Rutelinae), which are temporarily isolated and use the same sex pheromone compounds, (R)-buibuilactone and (R)-japonilure. Single sensillum recordings in A. octiescostata revealed highly sensitive olfactory receptor neurons (ORNs) (threshold <1 pg) that were tuned to the detection of the green leaf volatile compound (Z)-3-hexenyl acetate. As opposed to similar ORNs in another scarab species, Phyllopertha diversa, in A. octiescostata a diazo analogue elicited much lower neuronal responses than the natural ligand. Detectors for other floral and leaf compounds were also characterized. Extremely stereoselective ORNs tuned to sex pheromone were identified in male and female antennae. Biochemical investigations showed that, in A. octiescostata and A. cuprea, the pheromone-binding proteins (PBPs) isolated from male antennae were identical to PBPs obtained from female antennae. AoctPBP and AcupPBP had seven different amino acid residues. Binding of AoctPBP to (R)-japonilure is shown. PdivOBP1, which is also known to bind to (R)-japonilure, differed from AcupPBP in only two amino acid residues, one at the N-terminus and the other near the C-terminus. The structural features of the Bombyx mori PBP are compared with the sequences of eight known scarab odorant-binding proteins.
authors.affiliation: Laboratory of Chemical Prospecting, National Institute of Agrobiological Sciences, 1-2 Ohwashi, Tsukuba 305-8634, Japan.
authors.forename: Alexander Alexeevich
authors.initials: AA
authors.lastname: Nikonov
authors.forename: Guihong
authors.initials: G
authors.lastname: Peng
authors.forename: Galina
authors.initials: G
authors.lastname: Tsurupa
authors.forename: Walter Soares
authors.initials: WS
authors.lastname: Leal
mesh_terms: D000085:Acetates / Q000494:pharmacology; D000595:Amino Acid Sequence; D000818:Animals; D012831:Bombyx / Q000737:chemistry; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D001517:Coleoptera / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D004591:Electrophoresis, Polyacrylamide Gel / Q000379:methods; D005260:Female; D019476:Insect Proteins; D008297:Male; D013058:Mass Spectrometry; D008969:Molecular Sequence Data; D018034:Olfactory Receptor Neurons / Q000187:drug effects / Q000502:physiology*; D010675:Pheromones / Q000737:chemistry / Q000378:metabolism*; D018515:Plant Leaves / Q000737:chemistry; D017386:Sequence Homology, Amino Acid; D012903:Smell / Q000502:physiology*; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000085:Acetates; D002352:Carrier Proteins; D019476:Insect Proteins; D010675:Pheromones; C403713:pheromone binding protein, insect; C425828:3-hexenylacetate