J. David Warthen

Immune-depression in Rhodnius prolixus induced by the growth inhibitor, azadirachtin

Abstract Azadirachtin (1.0 μg/ml) if fed to last-instar larvae of Rhodnius prolixus through a blood meal, affects the immune reactivity as shown by (i) a significant reduction in numbers of haemocytes and nodule formation following challenge with Enterobacter cloacae B12 (ii) a reduction in ability to produce antibacterial and lysozyme activities in the haemolymph when inoculated with bacteria, (iii) a decreased ability of azadirachtin-treated insects to destroy the primary infection caused by inoculation of E. cloacae cells. However, the present experiments, unlike other immune reactions, fail to demonstrate any interference of azadirachtin with the prophenoloxidase-activating system since the melanin production was not reduced when this system was stimulated by trypsin or by the presence of bacteria in the haemolymph. It is suggested that the immune response is deficient in the azadirachtin-treated insects. The significance of these results is discussed in relation to the general mode of azadirachtin action in insects.

Deterrence coding by a larval Manduca chemosensory neurone mediating rejection of a non-host plant, Canna generalis L.

Abstract. The physiological basis of phagodeterrence was studied electrophy‐siologically and behaviourally in the phytophagous caterpillars Manduca sexta and Manduca quinquemaculata. The model unacceptable non‐host plant was the canna lily, Canna generalis.

Furanosesquiterpenoids from Commiphora myrrh oil

Abstract High-performance liquid chromatography has made possible the separation of furanosesquiterpenoids in Commiphora myrrh oil. Combined application of NMR, UV, and MS techniques have revealed that oil from C. myrrh gum resins contains isofuranogermacrene (1), lindestrene (2), furanoeudesma-1,3-diene (3), and furanodiene (4).

6-d-glucopyranosyl fatty acid esters from Brassica napus pollen

6-d-Glucopyranosyl esters of palmitic, oleic, linoleic and linolenic acids were identified in Brassica napus (rape) pollen. These esters are inactive as plant growth promoters in the bean second-internode bioassay.

Capillary gas chromatography method for the analysis of the trans isomers of ceralure, a medfly attractant

Abstract A capillary GC method has been developed to analyze laboratory or commercial samples of the medfly attractant ceralure [ethyl 4- (and 5-)iodo-trans-2-methylcyclohexane-1-carboxylate]. The method utilizes a specially prepared fused-silica column with a bonded phenyl-methyl polysiloxane liquid phase. Baseline separation was achieved for three of the four trans-ceralure isomers. Difficulties encountered with other columns investigated are also discussed.

The Occurrence of Dibutyl Phthalate in American Cockroaches

Abstract The presence of dibutyl phthalate in the American cockroach, Periplaneta americana (L.), was determined by means of gas chromatography-mass spectrometry. Each roach contained approximately 1.75 ppm of this compound. Since no source could be found in the rearing laboratories and since steps were taken to prevent contamination during laboratory processing, dibutyl phthalate apparently occurs naturally in the American cockroach.

Separation of cis and trans isomers from a mosquito repellent, CIC-4, via semi-preparative high-performance liquid chromatography and the repellent effect of each☆

Abstract CIC-4 (1,1,4,5,6,7,8,8a-octahydro-3H-2-benzopyran-3-one) is a fused bicyclic lactone which acts as a non-contact insect repellent for Aedes aegypti at 1% concentration in 95% aqueous ethanol when applied topically to rhesus monkeys. Chromatographic and spectroscopic analyses of a synthetic sample indicated the presence of cis-and trans-fused isomers. To supply each isomer for the assessment of mosquito repellent efficacy on humans, we developed a semi-preparative high-performance liquid chromatographic separation technique for the isomer separation. A column of 5-μm silica was used for isolating milligram quantities of each isomer. By this method, each isomer was obtained in > 95% gas-liquid chromatographic (GLC)-purity for biological evaluation. Supporting GLC and electron impact and chemical ionization gas chromatography-mass spectrometric data are also presented for each isomer. Biological evaluation on the human arm using Anopheles quadrimaculatus, Aedes aegypti, and Anopheles albimanus as the test species was effective in determining relative repellency to the standard N,N-diethyl-3-methyl-benzamide