Hiroshi Fukami

Sequestration of distasteful compounds by some pharmacophagous insects.

Several pharmacophagous insects have been shown to sequester specific kairomonal substances or their derivatives in their body tissues. Turnip sawflies,Athalia rosae, visit a plant,Clerodendron trichototmum (Verbenaceae), and feed voraciously on the leaf surface. Clerodendrins were characterized as the potent phagostimulants forA. rosae adults. The insect sequesters some of the analogs and becomes extremely bitter on its body surface. Some chrysomelid leaf beetles associated with cucurbitacins were found to store high concentrations of these bitter principles in their body. South American polyphagous beetles,Diabrotica speciosa andCerotoma arcuata, are strongly arrested by root components from the cucurbit plant,Ceratosanthes hilariana, and selectively accumulate 23,24-dihydrocucurbitacin D, effectively gaining bitterness. Similarly, four species of Asian pumpkin leaf beetles belonging to the genusAulacophora were shown to sequester the same compound in body tissue as the major bitter principle. Three phenylpropanoids closely related to methyl eugenol were found to accumulate in the rectal glands of the male Oriental fruit fly,Dacus dorsalis. One of the rectal gland components, 2-allyl-4,5-dimethoxyphenol was shown to be released in the air during courtship. In all of these cases, selectively sequestered compounds strongly deterred feeding by some predators, thus serving as allomones in this context. Kairomonal and pheromonal functions linked with allomonal sequestration by pharmacophagous feeding has also been suggested.

Accumulation of phenylpropanoids in the rectal glands of males of the Oriental fruit fly,Dacus dorsalis

Two phenylpropanoid compounds, 2-allyl-4,5-dimethoxyphenol(II) and coniferyl alcohol(III), were characterized from body tissue of wild males of the Oriental fruit fly,Dacus dorsalis. These compounds accumulated in the rectal glands only when laboratory-reared males were fed with methyl eugenol. Compound II was released into the air during dusk, which coincides with the fly courtship period. Pheromonal and allomonal effects of the phenylpropanoids were examined.

Sex Pheromone of the Almond Moth and the Indian Meal Moth: cis-9, trans-12-Tetradecadienyl Acetate

Female moths of different species but belonging to the same subfamily produce an identical compound as their sex pheromone. The sex pheromone of the almond moth, Cadra cautella (Walker), and the Indian meal moth, Plodia interpunctella (H�bner), has been isolated and identified as cis-9, trans-12-tetradecadienyl acetate.

Oviposition stimulants of aCitrus-feeding swallowtail butterfly,Papilio xuthus L

A methanolic extract ofCitrus unshiu induces oviposition by females of aCitrus-feeding swallowtail butterfly,Papilio xuthus L. The chemical factors responsible for stimulating oviposition were isolated and characterized as 5-hydroxy-Nω-methyltryptamine, adenosine, vicenin-2, narirutin, hesperidin and rutin. An artificial blend of these six components elicited significant oviposition behavior, apparently identical to that induced by contact with intactCitrus leaves.

The production of phytoalexins by oat in response to crown rust, Puccinia coronata f. sp. avenae

The antifungal compounds accumulated only in the incompatible host-parasite combinations; the time of rapid accumulation coincided with the time of the retardation of the growth of infection hyphae. Three major compounds were isolated. They are highly hydrophilic nitrogen-containing phenolics. Their antifungal activities against Puccinia coronata avenae and P. graminis tritici were demonstrated. They were regarded as phytoalexins and given the trivial names avenalumins I, II, and III. Avenalumins are the first nitrogen-containing phytoalexins found in plants and they are the first chemically-identified ones found in cereal plants in response to rust fungi.

Ecological adaptation of an Aristolochiaceae-feeding swallowtail butterfly,Atrophaneura alcinous, to aristolochic acids

Seven analogs of aristolochic acids (I, II, III, B, C, D, and E) were isolated from the leaves ofAristolochia debilis and characterized as the larval feeding stimulants of an Aristolochiaceae-feeding swallowtail butterfly,Atrophaneura alcinous. Aristolochic acids showed synergistic activity in combination with the water-soluble components in the leaf extract. Aristolochic acids were detected in the body tissues and specialized organs throughout all life stages ofA. alcinous. Larval osmeterial fluid contained aristolochic acids as high as 2% of the secretions, the compositions of which were similar to that found in the leaf extracts. In contrast, the eggs selectively contained aristolochic acids I and II. These two acids were present both in the egg yolk and egg coating material as well as in the collateral glands (glandulae sebaceae) of the adult females. The cannibalistic activity of the larvae against the eggs and pupae seemed to be triggered by aristolochic acids present on the egg surface and pupal cuticle, suggesting a possible adaptive mechanism in this species. Aristolocic acid I deterred feeding of tree sparrows, which suggested a defensive role against vertebrate predators.

Male sex pheromone of a giant danaine butterfly,Idea leuconoe

Males of a giant danaine butterfly,Idea leuconoe, display hairpencils during courtship. The females were visually attracted to and olfactorily arrested by an artificial butterfly model to which male hairpencil extracts were added. The hairpencil extracts contained a complex mixture of volatiles, including pyrrolizidine alkaloid (PA) derivatives (danaidone, viridifloric β-lactone), aromatics (phenol,p-cresol, benzoic acid), terpenoids (geranyl methyl thioether, (E,E)-farnesol), a series of γ-lactones (6-hydroxy-4-undecanolides and its homologs), hydrocarbons [(Z)-9-tricosene, etc.], and several compounds with higher molecular weight. A mixture of the major volatiles applied to a butterfly dummy strongly elicited an abdomen-curling acceptance posture in females. Viridifloric β-lactone and danaidone induced significant electroantennogram responses on the females antennae, suggesting their principal role together with other hairpencil components as a sex pheromone to seduce females.I. leuconoe males seem to acquire the precursor for both of the PA fragments from the host plant,Parsonsia laevigata (Apocynaceae), during the larval stage; thereby they do not show pharmacophagous behavior towards PA-containing plants during the adult stage. However, males are pharmacophagously attracted to and feed on a number of simple phenolic compounds in a manner similar to other danaine species towards PAs. Wild males sequester one of the phagostimulants, (−)-mellein, in the hairpencils in varying quantities. Phenolic compounds incorporated in the hairpencils may act primarily as warning odors linked with the defensive PAs present in the body tissues.

OVIPOSITION STIMULANTS OF AN ARISTOLOCHIACEAE-FEEDING SWALLOWTAIL BUTTERFLY, Atrophaneura alcinous

Oviposition stimulants of an Aristolochiaceae-feeding swallowtail butterfly,Atrophaneura alcinous, were isolated from the leaves ofAristolochla debilis and characterized as a mixture of aristolochic acids and sequoyitol. An artificial blend of these components applied to filter paper induced a significant oviposition response by the female butterflies, identical to that elicited by intact leaves of theAristolochia host plant.

Sex pheromone of the German cockroach (Blattella germanica L.) responsible for male wing-raising: 3,11-dimethyl-2-nonacosanone

Aus Cuticularwachs geschlechtsreifer Weibchen vonBlattella germanica (L.) wurde 3,11-Dimethyl-2-nonacosanon isoliert, das erwachsene Männchen der Art zum Balzverhalten anregt, wenn sie es mit ihren Antennen berühren.

γ-Glutamyl Transfer Reactions by Glutaminase from Pseudomonas nitroreducens IFO 12694 and Their Application for the Syntheses of Theanine and γ-Glutamylmethylamide.

In a mixture containing γ-glutamyl donor (donor) and γ-glutamyl acceptor (acceptor), the glutaminase of Pseudomonas nitroreducens IFO 12694 simultaneously catalyzed a γ-glutamyl transfer reaction and hydrolysis of the donor. The variation of the activities responding to the concentration of glutathione and glycylglycine indicated that the enzyme might be classified in a group of glutaminases that shows hydrolysis prior to transfer reaction. On the other hand, the results with glutamine and ethylamine or methylamine indicated that the enzyme was active in the transfer reaction with suppressed hydrolysis of glutamine, and suggested the possibility of using the reaction for producing γ-glutamylethylamide (theanine) or γ-glutamylmethylamide (γ-GMA). In fact, in a mixture containing high concentrations of substrates (0.7 M glutamine, 1.5 M ethylamine or methylamine) and 0.5 unit/ml glutaminase (borate buffer pH 11), 270 mM (47 g/L) theanine or 250 mM (38 g/L) γ-GMA was formed in 7 h of incubation at 30°C.