Orville L. Chapman

Sex pheromone chemistry of the female tobacco budworm moth, Heliothis virescens.

Abstract(Z)-11 -Hexadecenal (77–91%), (Z)-7-hexadecenal (0.1–2%), (Z)-9-hexadecenal (0.3–2%), hexadecanal (3–19%), (Z)-11-hexadecen-1-ol (1–5%), tetradecanal (1–3%), and (Z)-9-tetradecenal (1–3%) were identified from the heptane washes of the ovipositor of femaleHeliothis virescens (F.) females. In field bioassays, a 152-μg mixture of these seven compounds deployed in an insect trap exceeded the attractiveness of 4 virgin femaleH. virescens for males and was 5–6 times more attractive than a mixture of (Z)-1 1-hexadecenal and (Z)-9-tetradecenal (virelure) that was previously reported as the sex pheromone of the species. Four of the seven compounds produced byH. virescens females are also produced byH. zea (Boddie). Specificity of pheromonal signals among the two species is ostensibly dependent upon one or more of the three additional compounds [tetradecanal, (Z)-9-tetradecenal, and (Z)-1 1-hexadecen-1-ol] produced by femaleH. virescens.

Sex pheromone chemistry of female corn earworm moth, Heliothis zea.

Glass open-tubular capillary Chromatographic and combined glass open-tubular capillary chromatographic-mass spectrometric analyses of ovipositor washes of femaleHeliothis zea, chemical characterization, chemical synthesis, and laboratory and field bioassays showed that the ovipositor wash of the species is made up of 90–95% (Z)-11-hexadecenal, 1–2% (Z)-9-hexadecenal, 0.4–2% (Z)-7-hexadecenal, and 2–7% hexadecanal. Stimuli containing a binary mixture of (Z)-11-hexadecenal and (Z)-9-hexadecenal or the binary mixture in combination with any of the other aldehydes identified from the females elicited intense attraction and close-range precopulatory reactions fromH. zea males.

Trace chemicals: the essence of sexual communication systems in heliothis species.

Analysis of heptane-soluble compounds from ovipositors of Heliothis zea and Heliothis virescens shows that both species produce relatively large amounts of (Z)-11-hexadecenal, with traces of (Z)-9-hexadecenal, (Z)-7-hexadecenal, and hexadecanal. Heliothis virescens females differ from Heliothis zea in that they also produce trace amounts of tetradecanal, (Z)-9-tetradecenal, and (Z)-11-hexadecen-1-ol. In both species, trace compounds are essential to pheromonal activity and specificity of chemical signals.

Chemoreceptors in Lepidoptera: Stereochemical Differentiation of Dual Receptors for an Achiral Pheromone

The racemate and optically pure enantiomers of 9-(2-cyclopenten-1yl)nonyl acetate have been synthesized and shown to mimic certain biological properties of (Z)-11-tetradecenyl acetate. European corn borers and red-banded leaf rollers respond differently to the racemate and to the enantiomers in precopulatory behavior bioassay. The responses demonstrate the presence of two stereospecific chemoreceptors, show the chiral character of these receptors, and define the conformation of carbon atoms 10 to 14 of (Z)-11-tetradecenyl acetate in these receptors.

Chirality and stereochemical recognition in DNA-phytohormone interactions: A model approach

Space-filling molecular models of selected phytohormones and DNA, employed as described herein, illustrate possiblein vivo stereochemical recognition between nucleic acids and intercalated phytohormones. In this regard, the absolute chirality of certain phytohormones, and that of DNA may be essential for the recognition process. It is speculated further that the specific interactions shown by molecular models have significance in the evolution of plant regulatory mechanisms.

Suppression of male European corn borer sex attraction and precopulatory reactions with (E)-9-tetradecenyl acetate

Abstract(E)-9-Tetradecenyl acetate had previously been shown to be present in extracts of the female European corn borer,Ostrinia nubilalis (Hübner), along with (E)-11-tetradecenyl acetate, (Z)-11-tetradecenyl acetate, and tetradecyl acetate. In field and laboratory assays (E)-9-tetradecenyl acetate suppressed male attraction and precopulatory behavior, but tetradecyl acetate had no influence. The bioassay data indicate that (E)-9-tetradecenyl acetate and the isomeric 11-tetradecenyl acetates are perceived through separate sensory channels. A blend of (E)-9-tetradecenyl acetate and the 11-tetradecenyl acetates might be useful as a disrupter of mating efficiency of this pest species in the field.

Learning Science Involves Language, Experience, and Modeling

As we consider science learning, we must ask a fundamental question: What is science? The varying answers to this question traditionally have contributed to the gulf between physical science on the one hand and education and cognitive science on the other. Dialogue among practitioners must always make clear what we consider science to be. A catalogue of facts and a litany of big words usually define science instruction. But science is not a compendium of facts and big words. Science is a process for answering questions about nature. This paper presents learning science as involving three components, language, experience, and models, and discusses how information technology has an important role in each component.

Synthesis and x-ray crystal structures of poly-adamantane molecular rods

Abstract End-functionalized molecular rods composed of apically repeating adamantane units linked by double bonds are easily prepared in one step by a mixed McMurry coupling

Improvements in the synthesis of adamantane-2,6-dione and preparation of the novel adamantane-2,6-dione mono-ketal

Abstract A facile seven-step synthesis of adamantane-2,6-dione is presented that involves minimal purification, provides multigram quantities of product, and proceeds in an overall yield of 21%. The mono -ketal of adamantane-2,6-dione is obtained in 18% overall yield.

Stereochemical Evidence of Dual Chemoreceptors for an Achiral Sex Pheromone in Lepidoptera

Abstract The racemate and optically pure enantiomers of 9-(cyclopent-2-en-l-yl)nonyl acetate have been synthesized and found to mimic certain biological properties of a natural sex pheromone, Z -11-tetradecenyl acetate, European corn borer and redbanded leaf rollers respond differently to the racemate and to the enantiomers in precopulatory-behavior bioassay. The bioassay results demonstrate the resence of two stereospedfic chemoreceptors for the achiral pheromone, the chiral character of these chemoreceptors, and define the conformation of carbon atoms 10–14 of Z -ll-tetradecenyl acetate in each receptor. Specificity in communication is the adaptive advantage the insect gains by using two stereospedfic chemoreceptors with different conformational requirements for the achiral pheromone. The methodology described provides a new tool for neurochemical investigation of chemical sensing. A correlation of specific rotation and molecular weight is demonstrated for 3-subst1tuted cyclopentenes.