Novel verrucosins from the skin of the Mediterranean nudibranch Doris verrucosa

Gavagnin, Margherita; Ungur, Nicon; Castelluccio, Francesco; Cimino, Guido

doi:10.1016/s0040-4020(96)01083-6

Cited by 31 publications

(23 citation statements)

References 12 publications

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“…Extensive 2D NMR studies (Ή-Ή COSY, Ή-Ή TOCSY, HMQC, HMBC), along with homonuclear decoupling experiments, allowed complete NMR assignments (Table II), which were in good agreement with those reported in the literature for terpenoid models containing either the same functionalized ring A (O' Mathuna & Doskotch, 1994) or the same rings Β and C (Gavagnin et al, 1999c). The absolute configuration of 2 was suggested by comparing the CD profile with those of a series of isocopalane and eni-isocopalane diterpenoids, the absolute stereochemistries of which have been secured by synthesis (Ungur et al, 1996;Fontana et al, 1997b;Gavagnin et al 1997Gavagnin et al , 1999c.…”

Section: Austrodoris Kerguelenensissupporting

confidence: 84%

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Chemical studies on Antarctic nudibranch molluscs

Gavagnin¹,

Fontana²,

Ciavatta³

et al. 2000

Italian Journal of Zoology

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Two opisthobranchs, Austrodoris kerguelenensis and Bathydoris hodgsoni, collected from Antarctica in the framework of Spanish and German expeditions, were chemically investigated in order to identify the skin secondary metabolites, probably involved in the chemical defense of these molluscs. Some new terpenoid molecules were isolated from the mantle and their structures were established by spectroscopic methods, mainly by Nuclear Magnetic Resonance techniques. The absolute configuration at C-2' of the glyceryl moiety of diterpenoid 1,3-glyceryl esters from A. kerguelenensis was determined to be R by applying the modified Mosher method. Surprisingly, this configuration is the opposite of that of all marine terpenoid diacylglycerols so far reported. Other results described here were derived from synthetic studies on optically active terpenoid diacylglycerols, structurally related to the compounds isolated from A. kerguelenensis.

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Section: Austrodoris Kerguelenensissupporting

confidence: 84%

“…In the course of this investigation, we prepared a series of linear and cyclic optically active terpenoid glyceryl esters (Ungur et al, 1996, 1999, 2000, Fontana et al 1997bGavagnin et al, 1997Gavagnin et al, , 1999c.…”

Section: Synthesis Of Terpenoid Diacyl Glycerolsmentioning

confidence: 99%

Chemical studies on Antarctic nudibranch molluscs

Gavagnin¹,

Fontana²,

Ciavatta³

et al. 2000

Italian Journal of Zoology

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“…The characteristic metabolites of Doris 6errucosa are verrucosins, which are diacyl glycerols (Cimino et al 1988c;Avila et al 1990;Gavagnin et al 1990Gavagnin et al , 1997De Petrocellis et al 1996). These metabolites do not occur in the digestive gland, indicating de no6o synthesis, although experiments with labeled mevalonic acid gave poor incorporation, indicating that synthesis is slow.…”

Section: Nudibranchia: Dendronotacea and Arminaceamentioning

confidence: 99%

Chemical defense and evolutionary trends in biosynthetic capacity among dorid nudibranchs (Mollusca: Gastropoda: Opisthobranchia)

Cimino¹,

Ghiselin²

1999

Chemoecology

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119

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An evolutionary scenario incorporating recent advances in phylogenetic research begins with an opisthobranch-pulmonate common ancestor that was herbivorous and had some diet-derived chemical defense. The Nudibranchia and their closest relatives, the Notaspidea, form a lineage the ancestors of which had switched to feeding upon sponges and deriving protection from metabolites contained in them. Subsequently there have been repeated shifts in food and defensive metabolites, and trends are evident in the ability to detoxify, sequester and utilize metabolites from food, as well as to synthesize defensive compounds de no6o. The Notaspidea display a minor adaptive radiation that foreshadows a more extensive one in the various lineages of nudibranchs. This review emphasizes changes that have occurred within the Holohepatica, or dorid nudibranchs (order Doridacea). Their sister-group, the Cladohepatica, consists of three other orders, Dendronotacea, Arminacea, and Aeolidiacea, in which there has been a shift from sponges to Cnidaria as food. The Dendronotacea often feed upon Octocorallia, which combine spicules, chemical defense, and stinging capsules and thereby suggest a transition from feeding on sponges. A previous diet of Octocorallia is suggested by the defensive use of prostaglandins in the dendronotacean Tethys fimbria, which eats crustaceans. A shift to bryozoans in some Arminacea is accompanied by use of different metabolites. Dorid nudibranchs evidently began as sponge-feeders, but some lineages have shifted to a variety of other food organisms, and others have specialized in the kind of sponges they feed on and how they do it. There have been shifts to bryozoans (Ectoprocta) and ascidians (Chordata: Urochordata) that track metabolites rather than the taxonomy of the food. There is a crude correlation between the genealogy and the defensive metabolites of the sponge-feeding dorids.De no6o synthesis is well documented in this order and the metabolites are appropriately positioned so as to have an adaptive effect. The hypothesis that the capacity for de no6o synthesis was acquired by gene transfer across lineages is rejected, partly on the basis of different chirality of metabolites in the nudibranchs and their food organisms. Instead it is proposed that there has been a preadaptive phase followed by evolution in a retrosynthetic mode, with selection favoring enzymes that enhance the yield of end products that are already present in the food.

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“…Many dorid molluscs are chemically protected by some glycerides esterified at position 1-sn or 2-sn with terpenoid acids and acetate (Andersen and Sum, 1980;Gustafson and Andersen, 1985;Cimino et al, 1988Davies-Coleman and Faulkner, 1991;Soriente et al, 1993;Zubia et al, 1993;Gavagnin et al, 1995Gavagnin et al, , 1997Gavagnin et al, , 1999aKrug et al, 1995). The origin of these metabolites has been matter of discussion for long time.…”

Section: Biosynthesis In Nudibranchiamentioning

confidence: 99%

“…This mollusc is apparently well protected by both the mechanical defense of crystalline needles, named spicules, in the mantle and by the effective camouflage in the marine habitat. In addition, D. verrucosa contains in its mantles highly toxic glycerides (46-58) (Gavagnin et al, 1997). It has been reported that D. verrucosa possesses the ability to biosynthesize sterols (Avila et al, 1990) and xylosyl-methylthioadenosine (59) (Porcelli et al, 1989), an analogue of MTA that is very abundant (Cimino et al, 1986) in the hermaphrodite glands and in the egg-masses of the mollusc.…”

Section: Biosynthesis In Nudibranchiamentioning

confidence: 99%

Biosynthesis in opisthobranch molluscs: General outline in the light of recent use of stable isotopes

et al. 2004

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The use of stable isotopes has been recently introduced in the biosynthetic studies of metabolites produced by opisthobranch molluscs. This methodology offers numerous advantages since it avoids the complex and tedious manipulations of potentially dangerous radioactive compounds and gives unequivocal evidence for the incorporation. In these studies, high field NMR spectroscopy is a particularly useful tool to localize the labeled atoms in the molecule. This chapter updates the biosynthetic studies on opisthobranch molluscs with particular attention to the recent experiments with precursors labeled with stable isotopes. Opisthobranchs are able to biosynthesize de novo a wide array of chemical skeletons including polyketides, polypropionates, acetogenins, and terpenoids. The studies regarding this latter class is proposed in the light of the recent debate about classical and independent mevalonate pathway.

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Novel verrucosins from the skin of the Mediterranean nudibranch Doris verrucosa

Cited by 31 publications

References 12 publications

Chemical studies on Antarctic nudibranch molluscs

Chemical studies on Antarctic nudibranch molluscs

Chemical defense and evolutionary trends in biosynthetic capacity among dorid nudibranchs (Mollusca: Gastropoda: Opisthobranchia)

Biosynthesis in opisthobranch molluscs: General outline in the light of recent use of stable isotopes

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