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A new sesquiterpene lactone, furodysinin lactone, has been isolated from the sponge Dysidea etheria, along with the known furodysinin. The lactone was identified by detailed analysis of spectral data and by chemical correlation with furodysinin. The relative configuration of the newly discovered lactone was determined by lanthanide-induced chemical shift studies.Subsequent examination of the nudibranch Hypselodoris zebra, a predator of D. etheria, revealed the presence of high concentrations of several furanosesquiterpenes, including the known furodysinin and euryfuran, along with 5-acetoxy-and 5-hydroxy-nakafuran-8, both found previously in the Dysidea extracts. The feeding-deterrent properties of these compounds are discussed.Interest in chemical communication in the marine biosphere has increased markedly over the past few years. Recent reports (1-4) have concentrated principally on the relationships between sponges and nudibranches, frequent predators of sponges. As part of our continuing study of invertebrates from Bermudian waters (5-7), we have examined the chemical constituents of the sponge Dysidea etheria de Laubenfels and its predator, the nudibranch Hypselodoris zebra Heilprin. Described in this report are sesquiterpenes found in both organisms.Dysidea is a large genus widely distributed in tropical and subtropical waters around the world; D. etheria is a soft-bodied, bright blue sponge conspicuous in the low-light zones of the reef systems in Bermuda and the Caribbean. The nudibranch H. zebra was frequently observed grazing on D. etheria in Bermudian waters. When a single specimen of H. zebra was dissected and offered in separate portions to Abudefduf saxatilis, an omnivorous scavenger fish common on Bermuda's reefs, only the gonads were consumed. The digestive tract and outer skin were categorically rejected by the fish.Chromatography of the CH2C12 soluble extracts of D. etheria on Florisil gave 15 fractions. The most nonpolar fraction consisted primarily of one furanosesquiterpene; gel permeation and flash chromatography of this material gave a colorless oil that solidified in the cold. Mass spectral analysis revealed a molecular formula of C15H20O, and the fragmentation pattern, together with the 'H-nmr and inverse gated 13C-nmr data, left no doubt that this compound was the rearranged sesquiterpene furodysinin (1) (8).Gel permeation chromatography and subsequent reversed phase hplc of relatively polar fractions eluted with EtOAc and small percentages of MeOH in EtOAc yielded small quantities of a colorless solid, subsequently shown to be the sesquiterpene lactone 2.Inspection of the 13C-nmr spectral data for 2 revealed the presence of one carbonyl, two olefinic linkages, a quaternary sp3 carbon substituted by two heteroatoms ( 'Contribution #910 from the Bermuda Biological Station.

Male Galerucella calmariensis and Galerucella pusilla (Coleoptera: Chrysomelidae) emit an aggregation pheromone while feeding on host foliage. Isolation of the compound from collected volatiles was guided by comparisons of gas chromatograms of extracts from males and females and by gas chromatography-electroantennographic detection. The compound was identified by a combination of spectrometric methods and microchemical tests as the novel dimethylfuran lactone, 12,13-dimethyl-5,14-dioxabicyclo[9.2.1]tetradeca-1(13),11-dien-4-one. The structure was confirmed by synthesis, and the synthetic compound attracted males and females of both species in field bioassays. These beetles were previously introduced into North America as biological control agents for the invasive wetland weed, purple loosestrife Lythrum salicaria, and the pheromone could become a tool for monitoring populations. A new method is described for distinguishing the two species based on the tibial spurs of the males.

U-102408 has been isolated from S. arginensis cultures and fully characterized by NMR and MS. These studies indicate that U-102408 is identical with sulfomycin, and this data confirm the structure of sulfomycin which was assigned by chemical degradation and limited NMR studies. The biosynthetic origins of all U-102408 structural features have been elucidated through isotopic labeling experiments with primarily 13C but also using 14C, deuterium or tritium. Of particular interest, the 4-hydroxy-2-amino-2-pentenoic acid moiety was determined to originate from threonine and a one carbon unit derived from the two position of glycine or the S-methyl of methionine. The biosynthetic pathway for U-102408 differs from that for nosiheptide, thiostrepton, and berninamycin in that cysteine and serine do not cross label sites in U-102408, while this has been observed for the other thiopeptides. In U-102408 cysteine and serine are each incorporated into unique sites within the molecule. This indicates that the interconversion of cysteine and serine is not an active pathway for S. arginensis. In fact for fermentations in defined medium the addition of cysteine was found to be necessary to achieve higher antibiotic titer. Unlike the other thiopeptides that have been studied, threonine was incorporated into sites labeled by serine though serine did not incorporate into sites labeled by threonine within U-102408. No cross labeling of threonine and serine has been observed in studies of nosiheptide, thiostrepton, or berninamycin. In the current study glycine is investigated as a precursor for U-102408. The interconversion of glycine to serine is a very facile pathway in S. arginensis; glycine labels all sites labeled by serine. This data suggests glycine as a possible precursor for nosiheptide, thiostrepton, and berninamycin which has not been investigated for these other thiopeptides. Incorporation of label from 3-2H-serine is facile for thiostrepton and nosiheptide and was used to probe the mechanism of formation of the pyridine ring. However, no incorporation from 3-2H-serine or 3-3H-serine was observable for U-102408. While the lack of incorporation may be due to washout of the label from the precursor, it also may be due to the interconversion of serine and glycine causing loss of the label from the serine pool.

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