Diverticula in Male Lycorea halia Butterflies (Lepidoptera: Nymphalidae: Danaini: Itunina)-Support Organs for Everted Hairpencils with Unique Ultrastructure.

The involvement of the diverticula, a synapomorphy for Itunina, in protrusion and expansion of hairpencils by male Lycorea halia (Hübner, 1816) is demonstrated for the first time. They facilitate maintaining the haemolymph pressure necessary to keep the hairpencils everted. The diverticula are curved hook-like lobes, open to the body cavity and densely filled with tracheae and threads made by units of two staggered cells surrounding a central extracellular fibril bundle. Such complex structures, apparently metabolically active, have not been reported for insects previously and might indicate additional functions, but their functional role(s) remains a puzzle. When a male emerges from pupa, the diverticula are not yet formed; this happens only during the first protrusion of the hairpencils.

Pyrrolizidine alkaloids in food: a spectrum of potential health consequences.

Contamination of grain with 1,2-dehydropyrrolizidine ester alkaloids (dehydroPAs) and their N-oxides is responsible for large incidents of acute and subacute food poisoning, with high morbidity and mortality, in Africa and in central and south Asia. Herbal medicines and teas containing dehydroPAs have also caused fatalities in both developed and developing countries. There is now increasing recognition that some staple and widely consumed foods are sometimes contaminated by dehydroPAs and their N-oxides at levels that, while insufficient to cause acute poisoning, greatly exceed maximum tolerable daily intakes and/or maximum levels determined by a number of independent risk assessment authorities. This suggests that there may have been cases of disease in the past not recognised as resulting from dietary exposure to dehydroPAs. A review of the literature shows that there are a number of reports of liver disease where either exposure to dehydroPAs was suspected but no source was identified or a dehydroPA-aetiology was not considered but the symptoms and pathology suggests their involvement. DehydroPAs also cause progressive, chronic diseases such as cancer and pulmonary arterial hypertension but proof of their involvement in human cases of these chronic diseases, including sources of exposure to dehydroPAs, has generally been lacking. Growing recognition of hazardous levels of dehydroPAs in a range of common foods suggests that physicians and clinicians need to be alert to the possibility that these contaminants may, in some cases, be a possible cause of chronic diseases such as cirrhosis, pulmonary hypertension and cancer in humans.

Cognitive Performance of Patients with Epilepsy and Calcified Neurocysticercotic Lesions: A Case-Control Study.

Neuropsychological tests were applied to 20 patients with focal epilepsy related to calcified neurocysticercosis (NCC) (mean: three lesions/patient; NCC group), 22 patients with focal epilepsy without NCC (EPI group), and 29 healthy controls matched for age, sex, and educational level. The EPI and NCC groups were matched for age at onset of epilepsy, epilepsy duration, frequency of attacks, seizure semiology, interictal EEG findings, and antiepileptic drugs used. There were no differences in the digit span, word span, calculus, and Mini-Mental State examination among the three groups studied. The NCC and EPI groups showed lower scores than controls in immediate and delayed verbal memory, famous faces test, spatial recognition span, abstractions and judgment, and visuoconstructional abilities. The EPI group, but not the NCC group, also had lower scores in a praxis tests. There were no differences between the NCC and EPI groups in any of the tests applied (P > 15), except for the spatial recognition span, which was lower in the former. Cognitive impairment is a prevalent neuropsychological feature of patients with epilepsy and NCC.

The two facies of pyrrolizidine alkaloids: the role of the tertiary amine and its N-oxide in chemical defense of insects with acquired plant alkaloids.

Larvae of Creatonotos transiens (Lepidoptera, Arctiidae) and Zonocerus variegatus (Orthoptera, Pyrgomorphidae) ingest 14C-labeled senecionine and its N-oxide with the same efficiency but sequester the two tracers exclusively as N-oxide. Larvae of the non-sequestering Spodoptera littoralis eliminate efficiently the ingested alkaloids. During feeding on the two alkaloidal forms transient levels of senecionine (but not of the N-oxide) are built up in the haemolymph of S. littoralis larvae. Based on these results, senecionine [18O]N-oxide was fed to C. transiens larvae and Z. variegatus adults. The senecionine N-oxide recovered from the haemolymph of the two insects shows an almost complete loss of 18O label, indicating reduction of the orally fed N-oxide in the guts, uptake of the tertiary alkaloid and its re-N-oxidation in the haemolymph. The enzyme responsible for N-oxidation is a soluble mixed function monooxygenase. It was isolated from the haemolymph of the sequestering arctiid Tyria jacobaeae and purified to electrophoretic homogeneity. The enzyme is a flavoprotein with a native Mr of 200000 and a subunit Mr of 51000. It shows a pH optimum at 7.0, has its maximal activity at a temperature of 40-45 degrees C and an isoelectric point at pH 4.9. The reaction is strictly NADPH-dependent (Km 1.3 microM). From 20 pyrrolizidine alkaloids so far tested as substrates, the enyzme N-oxidizes only alkaloids with structural elements which are essential for hepatotoxic and genotoxic pyrrolizidine alkaloids (i.e. 1,2-double bond, esterification of the allylic hydroxyl group, presence of a second free or esterified hydroxyl group at carbon 7). A great variety of related alkaloids and xenobiotics were tested as substrate, none was accepted. The Km values of senecionine, monocrotaline and heliotrine, representing the three main types of pyrrolizidine alkaloids, are 1.3 microM, 12.5 microM and 290 microM, respectively. The novel enzyme was named senecionine N-oxygenase (SNO). The enzyme was partially purified from two other arctiids. The three SNOs show the same general substrate specificity but differ in their affinities towards the main structural types of pyrrolizidine alkaloids. The enzymes from the two generalists (Creatonotos transiens and Arctia caja) display a broader substrate affinity than the enzyme from the specialist (Tyria jacobaeae). The two molecular forms of pyrrolizidine alkaloids, the lipophilic protoxic tertiary amine and its hydrophilic nontoxic N-oxide are discussed in respect to their bioactivation and detoxification in mammals and their role as defensive chemicals in specialized insects. Pyrrolizidine-alkaloid-sequestering insects store the alkaloids as nontoxic N-oxides which are reduced in the guts of any potential insectivore. The lipophilic tertiary alkaloid is absorbed passively and then bioactivated by cytochrome P-450 oxidase.

Insect pheromone biosynthesis: stereochemical pathway of hydroxydanaidal production from alkaloidal precursors in Creatonotos transiens (Lepidoptera, Arctiidae).

The mechanism by which the moth Creatonotos transiens produces its male pheromone, (7R)-hydroxydanaidal, from heliotrine, an alkaloidal precursor of opposite (7S) stereochemistry, was investigated. Specifically deuteriated samples of heliotrine and epiheliotrine were prepared and fed to C. transiens larvae, and the steps in the biosynthetic process were monitored by gas chromatography/mass spectrometry. These analyses indicate that heliotrine is initially epimerized to (7S)-epiheliotrine by oxidation to the corresponding ketone followed by stereospecific reduction. The order of the subsequent steps is (i) aromatization of the dihydropyrrole ring, (ii) ester hydrolysis, and (iii) oxidation of the resulting primary alcohol to the final aldehyde. The ecological implications of this insect's ability (and the inability of another moth, Utetheisa ornatrix) to use representatives of two stereochemical families of alkaloids as pheromone precursors are discussed.

THE CLADISTICS OF AMAURIS BUTTERFLIES: CONGRUENCE, CONSENSUS AND TOTAL EVIDENCE.

Abstract- Two data sets for 10 species of African milkweed butterflies (Nymphalidae, Danainae: one Danaus, two Tirumala, seven Amauris) have been analysed cladistically, separately and in combination. One data set comprised 32 morphological characters, the other comprised 68 chemical compounds from male scent organs. Analysed separately, the two data sets produced six similar but non-identical minimum-length solutions. Analysed together, the combined data set of 100 characters produced a single minimum-length tree, identical to one of the three solutions for the morphological data set. The combined data produced a more informative result than congruence comparisons based on strict or combinable component consensus analysis. These results, together with re-analysis of a morphological data set for all 15 species of Amauris (which produced 12 minimum-length solutions), permit increased resolution of the existing classification of this Afrotropical genus, including the formal recognition of two subgenera, Amauris (Amauris) Hübner, and Amauris (Amaura) Geyer (stat. rev.). The fit of uniquely derived, unreversed chemical characters to the tree raises the possibility that stepwise additive evolution of semiochemicals may have occurred during cladogenesis of these mimetic butterflies. The implications for chemoecology and speciation are briefly discussed.

Lepidoptera and pyrrolizidine alkaloids Exemplification of complexity in chemical ecology.

Pyrrolizidine alkaloids (PAs) are defensive secondary metabolites found in numerous plant groups. Various insects belonging to different orders have special requirements for these compounds and sequester them from such plants for their own defense and often as pheromone precursors. The fitness of these insects depends on PAs and, in some cases, PAs even act as regulators of androconial organ development. This article discusses selected behavioral, chemical, physiological, and phylogenetic aspects of insect-PA relationships, and raises questions about the complex interactions of the variety of PA-related adaptations as they occur among a diverse array of species. Although many superficial similarities are recognized, few generalizations can yet be drawn. However, insect-PA relationships not only exemplify basic features of chemical ecology but illustrate a multiplicity of aspects and adaptations, which we should expect to find in any thorough study of insect-plant relationship.

Carboxylic acids from hairpencils of male Amauris butterflies (Lep.: Danainae).

63 Carboxylic acids were identified from the male hairpencils of four species of the genus Amauris (Lep.: Danainae), namely A. echeria (Stoll), A. hecate (Butler), A. ochlea (Boisduval) and A. albimaculata Butler. Straight chain saturated as well as unsaturated carboxylic acids, some of which containing an additional oxygen function, contribute to the species-specificity of the odour bouquets. Oxygenated fatty acids form a new class of insect volatiles, 5 of the 10 ketoacids found represent new natural products. (E)-7-Oxo-11-tetradecenoic acid is the main volatile component of the hairpencils of A. echeria, the species with the highest amount of oxygenated fatty acids (70% of the extractable volatiles). 9-Hydroxyoctadecanoic acid is a major compound in both A. ochlea and A. albimaculata while in A. hecate oxygenated carboxylic acids are present in minute amounts only.

CO2 sensitive receptors on labial palps of Rhodogastria moths (Lepidoptera: Arctiidae): physiology, fine structure and central projection.

The tips of the labial palps of Rhodogastria possess a pit housing uniform sensilla, histologically characterized by wall-pores and receptor cells with lamellated outer dendrites. The receptor cell axons project to glomeruli in the deutocerebrum which are not innervated by antennal receptors. From their histology as well as from their central projection these sense organs are identical with palpal pit organs of other Lepidoptera (Lee et al. 1985; Kent et al. 1986; Lee and Altner 1986). Physiologically, the palp-pit receptors respond uniformly; they are most excitable by stimulation with carbon dioxide while they exhibit relatively moderate responses to various odorants. The responses to CO2 show a steep dose-response characteristic. In ambient atmosphere (i.e., ca. 0.03% CO2) the cells are in an excited condition already; the seeming 'spontaneous activity' exhibited in air is decreased if the preparation is kept under N2 or O2 or CO2-free air. There is hardly any adaptation of the responses to continuous or repeated stimulation. Perhaps CO2 sensitivity is correlated with sensilla characterized by both wall-pores and lamellated dendrites. Pilot tests indicate that CO2 perception might be widespread in the Lepidoptera, but the biological significance remains obscure.

Stereochemical course of pheromone biosynthesis in the arctiid moth, Creatonotos transiens.

The biosynthetic conversion of a pyrrolizidine alkaloid (heliotrine, IV) to a male moth pheromone (hydroxydanaidal, III) is found to proceed with inversion of configuration at the remaining asymmetric center (C-7).

Scent organ development in creatonotos moths: regulation by pyrrolizidine alkaloids.

7-Hydroxy-6,7-dihydro-5H-pyrolizine-1-carboxaldehyde is the major volatile component of the scent organs in males of two species of Creatonotos (Lepidoptera, Arctiidae). The biosynthesis of this presumed pheromone depends on the presence of pyrrolizidine alkaloids in plants that are ingested by the larvae. In addition, these secondary plant substances control the morphogenesis of the scent organs. This morphogenetic effect of an alkaloid has not been observed previously.