Dora K. Hayes

Identification of a neuropeptide hormone that regulates sex pheromone production in female moths

A pheromone biosynthesis activating neuropeptide (PBAN) hormone that controls sex pheromone production in female moths was identified from the brain-subesophageal ganglion complexes of the adult corn earworm, Heliothis zea. PBAN has 33 amino acid residues and a molecular weight of 3900. Its amino acid sequence has no significant homology with any of the fully characterized peptide hormones. The synthetic peptide, at a dose of between 2 and 4 picomoles, induced production of a normal quantity of sex pheromone in ligated H. zea females. The peptide also induced pheromone production in six other species of moths, thus indicating that this or similar peptides may be responsible for the regulation of pheromone production in moths.

Isolation and primary structure of a peptide from the corpora cardiaca of Heliothis zea with adipokinetic activity

An adipokinetic hormone was isolated from the corpora cardiaca of the corn ear worm moth, Heliothis zea, and purified by reversed phase high performance liquid chromatography. The primary structure, pGlu-Leu-Thr-Phe-Thr-Ser-Ser-Trp-Gly-NH2, was determined by automated gas-phase Edman degradation of the peptide deblocked with pyroglutamic aminopeptidase, and by fast atom bombardment mass spectrometry. The hormone was synthesized and the natural and synthetic material had identical chromatographic, spectroscopic, and biological properties. The peptide was found to have lipid mobilizing activity in H. zea adults.

Isolation and primary structure of a neuropeptide hormone from Heliothis zea with hypertrehalosemic and adipokinetic activities

A neuropeptide was isolated from the corpora cardiaca of the corn earworm moth Heliothis zea, and purified by sequential gradient elution in three reversed phase-high performance liquid chromatographic steps. The primary structure, pGlu-Leu-Thr-Phe-Ser-Ser-Gly-Trp-Gly-Asn-NH2 was determined by automated gas-phase Edman degradation of the peptide deblocked with pyroglutamate aminopeptidase, and confirmed by fast atom bombardment mass spectrometry. The hormone was synthesized and the natural and synthetic peptides had identical chromatographic and spectroscopic properties. Both natural and synthetic hormones caused the elevation of trehalose and lipid levels in the hemolymph of adult H. zea males.

Critical periods for the brain and prothoracic glands of 5th instars of the European corn borer, Ostrinia nubilalis hubner☆

1. 1. Classical ligation techniques were used to determine the critical periods for the head and the prothoracic glands in the larval-pupal molt of the European corn borer. 2. 2. Most larvae reared under LD 16:8 and 30°C released sufficient PTTH between lights on + 13 hr and lights on — 3 hr to stimulate the prothoracic glands to produce ecdysone. 3. 3. Ecdysone was first released just before lights on, with almost all larvae having produced sufficient ecdysone to elicit a molt by lights on + 6 hr. 4. 4. Critical periods for the brain and prothoracic glands of Ostrinia are compared with those of other lepidopterans.

Isolation of two neuropeptides in the AKH/RPCH-family from horseflies (diptera)

Two neuropeptides (DCCI and DCCII) in the adipokinetic/red pigment concentrating hormone-family have been isolated and purified from the corpora cardiaca of horseflies (Diptera : Tabanidae). Both peptides were purified by a sequence of three reversed phase-high performance liquid chromatographic steps. Amino acid analysis of the purified peptides indicated the following composition for DCCI: Glx(l), Gly(1), Leu(1), Phe(1), Pro(1), Thr(2) and for DCCII: Glx(1), Gly(2), Leu(1), Phe(1), Pro(1), Thr(2), and Tyr(1). Photodiode array ultraviolet spectroscopy indicated the presence of tryptophan in both DCCI and II. Both DCCI and II had red pigment concentrating hormone activity in the crab, Uca pugilator.

HPLC Isolation and Purification of Pheromone Biosynthesis Activating Neuropeptide of Heliothis Zea

A pheromone biosynthesis activating neuropeptide hormone (PBAN) of Heliothis Zea has been recently reported by Raina and Klun (1984). This paper reports the isolation and purification of PBAN in addition to data on recovery of biological activity from various workups, molecular weight and amino acid analysis.

Partial Purification of a Receptor for the Adipokinetic Hormones from Musca Autumnalis Face Flies

Partial purification of the receptors for the neurohormones, diptera corpora cardiaca factors 1 and 2 (DCC1 and DCC2) was achieved. Receptor proteins were obtained from the abdomens of face fly, Musca autumnalis De Geer. Purification methods included detergent solubilization, affinity chromatography, and polyacrylamide gel electrophoresis. Analysis by gel electrophoresis has identified two proteins from this partial purification with relative molecular weights of 45 and 90 kD. A crude receptor preparation was used to develop a ligand binding assay with radiolabeled (tritiated and iodinated) DCC1. Ligand binding was inhibited by 90% when excess unlabeled DCC1 was added to the assay mixture. Ligand binding was optimum at pH 7.5. Binding saturation occurred at approximately 12 picomole radiolabeled ligand concentration. Because DCC1 and DCC2 have been shown to effect the lipid and trehalose levels in the insect an understanding of the neuropeptide-receptor interaction is important for the development of new methods of control of dairy and poultry muscoid flies.

Implantable Systems for Delivery of Insect Growth Regulators to Livestock.II

During the past several years, our laboratories have been investigating the application of controlled-release technology to the control of arthropod pests of livestock.1 As a result we have developed methods whereby an active ingredient can be delivered at a controlled rate into the circulatory system of a host animal via implanted pellets or microcapsules to affect feeding parasitic insects or ticks. Our initial experiments involved the preparation and bioevaluation of injectable microcapsules of the systemic pesticide famphur (O-[p-(dimethylsulfamoyl)phenyl]O, O-dimethyl phosphorothioate) in biodegradable polymers.2 Subcutaneous injections of a suspension of these microcapsules into guinea pigs killed feeding ticks over an extended period by continuously releasing active ingredient into the host’s circulatory system. However, large injections were required because of the relatively low activity of famphur and the volume of sesame oil used to suspend the microcapsules. Thus, this treatment was impractical for cattle. We therefore sought to avoid these problems by developing controlled-release implants of systemic insect growth regulators (IGR’s).

Cyclic 3′,5′-AMP phosphodiesterase activity in head extracts of the five larval instars of the European corn borer, Ostrinia nubilalis (Hüber), and in extracts of brains of the fifth instar

Abstract 1. Cyclic 3′,5′-AMP phosphodiesterase activity in homogenates of heads of the 5 instars of the European corn borer, Ostrinia nubilalis (Hubner), was determined after the insect larvae had been exposed to light regimens of LD 16:8 (16 hr light, hr dark) or LD 10:14. 2. Larval head capsule width was determined for each of the 5 instars and it was found to vary from an average of 0.29 mm in the first instar to an average of 1.9 mm in the 5th instar. 3. Enzyme activity of larvae reared under both light regimens increased during instars 1, 2 and 3, reached a peak in instar 3 or 4, and decreased to undetectable levels during instar 4. 4. Enzyme activity in heads of 3rd-instar larvae held in LD 16:8 was higher than in heads of 3rd-instar larvae held in LD 10:14. 5. Enzyme activity was undetectable in diapausing insects, but it peaked again in the prepupa. 6. The results provide additional evidence that cAMP-ase is significant in insect metamorphosis and also suggest that this enzyme may be involved in insect photoperiodism. 7. Although cAMP-ase activity was determined in as few as 2 brains from 5th-instar larvae, total phosphodiesterase activity of the larval brains was the same whether insects were reared in LD 16:8 or in LD 10:14 and whether the insects were in diapause.

Circadian rhythm of trehalose in the face fly Musca autumnalis De Geer.

Trehalose levels were determined over two 24 hr spans in groups of face fly adults 3-4 days after emergence from the puparium. Face fly pupae were placed in rearing chambers at 27 degrees C in a staggered light-dark regimen, LD 16:8, so that at a given clock hour, samples could be obtained at several different hours after lights on (HALO). Trehalose was determined in hemolymph collected from a puncture in the intersegmental membrane of the abdomen. Treated hemolymph samples were passed through a Bio-Rad Amino 5-S disaccharide column and a Waters 410 refractive index detector was used to differentiate among sugars. The circadian acrophase derived by cosinor analysis in hemolymph trehalose (when the values were 25.49 and 26.86 micrograms/microliters on the first and second days respectively) occurred at -226 degrees (ca 15 HALO) and the bathyphase at 24 HALO. The mesor = 11.82 micrograms/microliters trehalose, the amplitude = 8.57 micrograms/microliters trehalose and the P-value for presence of a rhythm was 0.003. Based on these data, differences between control and test flies in a bioassay of hypertrehalosemic activity would be most easily observed at 0-8 HALO, while exogenous hypotrehalosemic activity would be best assayed at 12-20 HALO.