nobuhiro shimizu

Although adult sycamore lace bugs Corythucha ciliata (Say) show no sign of aggregation, nymphs at all developing stages are gregarious. When an individual nymph in the center of a colony was squashed with a needlepoint, proximate nymphs showed evasive behavior. The same evasive reaction was produced by exposing aggregated nymphs to nymph hexane extract. The active component, E-3,7-dimethyl-2,6-octadien-1-ol, geraniol, was responsible for the evasive behavior, and identified as the alarm pheromone. One nanogram of the alarm pheromone elicited activity similar to that in a third instar nymph. Presence of 2-acylcyclohexane-1,3-diones and their 4-hydroxy analogues are reconfirmed as nymph-specific components, though their biological significance remains unknown.

A total of fifteen saturated fatty acid esters were newly identified from the secretions of an unidentified Anaulaciulus sp. (Julida: Julidae). The fatty acid components of the esters were composed of normal chain acids (from C(10) to C(14)) and of branched chain acids (from iso-C(12) to iso-C(15) and anteiso-C(15)). The alcohol moieties were all composed of normal chain alcohols varying from n-butanol to n-octanol. The most abundant component found in the total esters was n-hexyl laurate (64.7%). Novel compounds identified from the millipede secretion extracts include six branched iso- and anteiso-fatty esters, an odd-numbered C(11)-fatty acid ester, a C(13)-fatty acid ester, and a C(7)-alcohol ester, all of which were previously undescribed natural products. In addition, a characteristic mixture of benzoquinones, such as 2-methyl-1,4-benzoquinone, 2-methoxy-3-methyl-1,4-benzoquinone, 2,3-dimethoxy-1,4-benzoquinone, 2-methoxy-6-methyl-1,4-benzoquinone, and 2,3-dimethoxy-5-methyl-1,4-benzoquinone were identified from the secretions, together with trace amounts of 1,4-benzoquinone.

The opisthonotal gland secretion of the acarid mite, Caloglyphus polyphyllae, contained two new monoterpenes, (E)-2-(2-hydroxyethylidene)-6-methyl-5-heptenal (1) and (E)-2-(2-hydroxyethyl)-6-methyl-2,5-heptadienal (2), to which we have given the trivial names alpha- and beta-acariolal in relation to alpha- and beta-acaridial (3 and 4), respectively. Elucidation of the structure of 1 was established mainly from 1H-NMR and GC/MS spectral data after partial purification, together with the fact that 1 was recovered in the more-polar fraction from a silica gel column than alpha- and beta-acaridial (3 and 4) present in the secretion. Compound 2 was obtained in the same fraction as a mixture with 1. Based on the facts that 2 had the same molecular weight by GC/MS and the same polarity as that of 1, compound 2 was assumed to be a structural analog of 1. The structures of compounds 1 and 2 were confirmed by their synthesis in nine and ten respective steps starting from alpha-bromo-gamma-butyrolactone.

The concise synthesis of 5,6-dihydrovaltrate (2), the bioisostere of valtrate (1) showing anti-HIV activity by inhibition for nuclear export of Rev, has been achieved from the commercially available iridoid genipin (3). Analysis of steric influence of the substituents linked to the three hydroxyl groups was conducted by the synthesized three analogs (2a-2c). Consequently, attenuation of steric hindrance around the epoxy portion was revealed to enhance inhibitory potency for Rev-export. In addition to this finding, 1-acetoxy analog 2b was disclosed as the promising Rev-export inhibitor superior to 1.

Significance Aliphatic formates are commonly detected in astigmatid mite secretions and have been considered for roles in pheromone communication. Despite the natural occurrence of aliphatic formates, details surrounding the biosynthetic pathways remain unclear. To probe the biosynthetic mechanism, we performed 13 C-incorporation experiments targeting two different chain-like aliphatic formates by feeding with suitable labeled precursors. Results support a mechanism whereby formates are generated via the Baeyer–Villiger oxidation of aldehydes as direct precursors. The enzyme that catalyzes this reaction has yet to be identified in animals, microbes, and plants. Results from the labeling studies inform approaches to identify the specific gene and encoded enzyme responsible for aliphatic formate biosynthesis, which will enable a facile dehomologation method in the field of organic synthesis.