Molluscs chemical defenses

Becerro MA, Starmer JA, PaulVJ, Chemical defenses of cryptic and aposematic gastropterid molluscs feeding on their host sponge dysidea gtznuXosz., Journal of Chemical Ecology 52 (7) l491—1500, 2006. 

Becerro MA, Starmer JA, Paul VJ (2006) Chemical Defenses of Cryptic and Aposematic Gastropterid Molluscs Feeding on Their Host Sponge Dysidea granulosa. J Chem Ecol 32 1491... 

Faulkner, D. J., Chemical defense of marine molluscs, in Ecological Roles of Marine Natural Products, Paul, V. J., Ed., Cornell University Press, Ithaca, NY, 1992, 119. 

Cimino, G. and Ghiselin, M. T., Chemical defense and evolution in the Sacoglossa (Molluscs Gastropoda Opistobranchia), Chemoecology, 8, 51, 1998. 

Cimino, G., De Rosa, S., De Stefano, S., Morrone, R., and Sodano, G., The chemical defense of nudibranch molluscs. Structure, biosynthetic origin and defensive properties of terpenoids from the dorid nudibranch Dendrodoris grandiflora, Tetrahedron, 41, 1093, 1985. 

Avila, C. and Durfort, M., Histology of epithelia and mantle glands of selected species of doridacean molluscs with chemical defensive strategies, Veliger, 39, 148, 1996. 

McClintock, J. B., Baker, B. J., Slattery, M., Heine, J. N., Bryan, P. J., Yoshida, W., Davies-Coleman, M. T., and Faulkner, D. J., Chemical defense of common Antarctic shallow-water nudibranch Tri-toniella belli Eliot (Molluscs Tritonidae) and its prey Clavularia frankliniana Rouel (Cnidaria Octocorallia), J. Chem. Ecol., 20, 3361, 1994. 

Bathydoris hodgsoni can be found in the deep waters of the Weddell Sea. This nudibranch elaborates the drimane sesquiterpene hodgsonal (Structure 7.78) and sequesters it in its mantle tissues.50 164The nudibranch Tritoniella belli collected from McMurdo Sound is the only documented example of an Antarctic mollusc sequestering defensive chemistry from its diet.44 Among the glyceride esters (Structures 7.79-7.81) isolated from this species, chimyl alcohol (Structure 7.79) can also be found in one of its prey items, the stoloniferan coral Clavularia frankliniana. Sequestration of these defensive chemicals is opportunistic, however, and other, still undescribed metabolites are more commonly associated with defense in this mollusc.49... 

In the bright yellow lamellarian Marseniopsis mollis, soft mantle tissue covers a reduced shell, which makes this species, similar to opisthobranchs, susceptible to predation. In the first demonstration of chemical defense in a prosobranch mollusc, ecologically relevant concentrations of homarine, which is present in high concentrations in the tissues of Marseniopsis mollis, caused... 

Wink, M. 1984. Chemical defense of lupins. Mollusc-repellent properties of quinolizidine alkaloids. Z. Naturforsch. 39c, 553-558... 

D. J. Faulkner, Chemical Defenses of Marine Molluscs. In Ecological Roles of Marine Natural Products V. J. Paul, Ed. Cornell University Press Ithaca, 1992 pp 119-163. 

Marine dinoflagellates produce a number of toxins, such as saxitoxin, surugatoxin, tetrodotoxin, and gonyautoxin, that affect ion channels (Table IV). These algae are eaten by some copepods, fish, and molluscs that also store these neurotoxins 4,17,28,29,494,495). As a consequence, these animals have acquired chemical defense compounds, which they can use against predators. 

Marine pulmonates of the genus Siphonaria are air breathing molluscs that resemble limpets with which they co-occur in the intertidal zone. Nearly all specimens examined contained polypropionate metabolites that are believed to be employed in chemical defense against predators. Siphonaria diemenensis collected intertidally in southeastern Australia contained two antibiotics, diemenensin-A ( 2) and -B (883)... 

CiMiNO, G., S. DE Rosa, S. de Stefano, R. Morrone, and G. Sodano The Chemical Defense of Nudibranch Molluscs. Structure, Biosynthetic Origin, and Defensive Properties of Terpenoids from the Dorid Nudibranch Dendrodoris grandiflora. Tetrahedron 41, 1093 (1985). 

An illuminating example of a community consequence of plant defensive metabolites, and of a grazer s adaptation to exploit its host plant, is the ability of some herbivores to sequester plant-derived secondary metabolites for their own defenses (e.g., Avila 1995 Marin and Ros 2004). In terrestrial systems, several specialist insects can sequester defensive chemicals from their host plants (e.g., Nishida 2002), but in aquatic plant-herbivore systems with a prevalence of generalist herbivores this is less common. However, sea hares (Anaspidea) and some other herbivorous opisthobranch molluscs are known to be able to sequester defenses from their algal foods (Avila 1995 Marin and Ros 2004). For the opisthobranch species that are known to obtain metabolites from their food, algae were the... 

Many species of marine molluscs are physically defended from predation by the presence of a hard shell or by the ingestion of undischarged nematocysts. The need for soft shelled or soft bodied molluscs to have an alternative, chemically-based defensive mechanism was first explored by Faulkner and Ghiselin.230 When molested, many species of mollusc secrete a mucus that is deterrent to predators and which has been shown to be toxic 131 180 231 232 many mollusc extracts are toxic.233... 

Molluscs can be divided into two biosynthetic categories based on the chemistry they exhibit relative to their diet those that are dependent on dietary sources express chemistry that reflects their choice of diet. In some instances, molluscs have been shown to chemically modify the ingested compounds. These transformations may either enhance the deterrent nature of the metabolite or alternatively represent a detoxification mechanism examples of both are documented below. The second category of molluscs are those which have the ability to biosynthesize metabolites de novo and, hence, may sometimes express a preference for a diet lacking secondary metabolites. The expense of maintaining secondary metabolic function is balanced against the lack of dietary constraints. Molluscs that can produce their own defensive allomones are likely to have an advantage over those dependent on a dietary source of metabolites. 

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