1. Anjaneyulu ASR, Prakash CVS, Raju KVS, Mallavadhani UV. 1992.
Isolation of new aromatic derivatives from a marine algal species Caulerpa racemosa.
J Natural Products 55(4): 496-499.
summary: produce acetylenic sequiterpenoids, triterpenoids, nitrogenous compounds in addition to the red pigment, caulerpin.
Along with caulerpin is a colorless toxic substance; a mixture of N-acyl sphingosines and sitosterol. 5 new propane dimer compounds found -
uncommon aromatic derivatives not usually found in marine algae.
2. Faulkner, DJ. 1988. Marine Natural Products. Natural Products
Reports. 615-616 University of California, San Diego, Scripps Institute of Oceanography, La Jolla, CA 92093 USA
summary: caulerpin and its corresponding diacid show activity similar
to indoleacetic acid - six new sesquiterpenes isolated from C. ashmeadii and
found toxic to damselfish and showed antimicrobial activity.
3. Hashimoto Y. and Fusetani N. 1972. Screening of the toxic algae on coral reefs.
Proceedings of the International Seaweed Symposium 7: 569-572.
summary: caulerpicin and caulerpin, toxic substances of the genus
Caulerpa, accumulate in the food chain - found in gastropods, surgeonfish and soft corals
but found comapratively non-toxic to mammals.
4. McConnell Oliver J., Hughes Patricia A.,, Targett Nancy M, Daley
Joyce. 1982. Effects of secondary metabolites from marine algae on feeding by the sea urchin, Lytechinus variegatus.
J Chemical Ecology 8(12): 1437-1453.
summary: C. prolifera: caulerpenyne (oxygenated sesquiterpene)
C. racemosa and C. ahmaedii contained caulerpin caulerpenyne and
extract from C. prolifera redeces urchin herbivory by 50%,singificantly - even at 0.4% of fresh weight and 0.1% extract
although very high levels of caulerpin in other species, feeding not detreed in the urchin
(believed for this urchin to be a chemical attractant as it is
toxic to other animals)
5. Meinesz, Alexandre and Simberloff, Daniel. 1999. Killer Algae.
University of Chicago Press, Chicago. pp. 295-304.
summary: mainly concerns the highly problematic C. taxifolia (I'm sure
you can get plenty of information on this puppy!). Caulerpales have
specific anatomy of no internal cell walls and therefore no specialized cells.
When cut a milsky "sap" flows out with carbohydrte plug formed quickly.
Liquid occupies entire cavity of the algae. Compsoed of three elements:
stolon, fronds and rhizoids. Stolon can be over 2m in length andis branched.
Greek caulos meaning stem and erpo meaning creep. rhizoids penetrate every surface
and adapt to bottom texture (long in sand or mud, short in rock) axes can grwo up to 2cm/day,
elongteing at one end and dying at the other, no part of thallus lives more than a year.
Leads to rapdily dense colonies that then compeete with plants and sessile animals. up to 8200 frons/square meter.
When axes die, colony becomes fragmented. Each fragment, so long as it contains a
nucleus, can form a new alga and all fragments likely contain numerous
nuclei. 1cm fragment can produce 3m colony in 6 months. Reproduction
follows an unusal strategy - several days each year, nucleus joins with
chloroplast, surrounds itself with a membrane and transforms into male or female gamte,
expelled through small orfiices and the plant dies (no cell walls, so everythingis lost).
Plants are monecious (both sexxes in same plant) and gametes are about 5 micrometeres- passage from egg to palnt takes 3-6 months -
puts pretty much everything into sexual reproduction and is designed that way. Caulerpa includes nearly 100 species -
most of those we keep are both tropical and temperate (prolifera, taxifolia, racemosa, mexicana, crassifolia)
6. Littler, Diane Scullion and Littler, Mark Masterson. 2000. Caribbean
Reef Plants. OffShore Graphics Inc, Washington, D.C. pp. 356-380
summary: Caulerpa racemosa overtops and kills reef-building corals.
textbook (didnââ"šÂ¬Ã¢"žÂ¢t get the reference information) Introduction to the
Algae pp. 229-230 "the production of a deadly posion by species of Caulerpa,
referred to as caulerpicin... is known to enter marine food chains.
7. Paul, Valerie J., and Fenical, William. 1986. Chemical defense in
tropical green algae, order Caulerpales. Marine Ecology Progress Series
34: 157-169
summary - ok, this is the mother lode....
40 species of Caulerpa chemically investigated. "virtually all produce
toxic seconary metabolites of a unique and unprecedented class. These
metabolites are generally linear terpenoids, but unsual structural features
such as aldehydes and bis-enol acetate functional groups makes these compounds unqiue.
the compounds are toxic or deterrent towards microorganisms,s ea urchin larvae, and herbivorous fishes,
and when incorporated into diets at naturally occurring concentrations casue mortality in juvenile conch.
Concentrations of bioactive metabolites were found to show liittle variation in different plant parts such as baldes,
stipes, and holdfasts." Young growing tips and reproductive structures contained
higher concentartions than mature plant tissues on dry weight basis (i.e. youprune it, you get more toxins).
Qualitative and quantitative variation observed in different populations of the same species.
Highest herbivory = greatest concentrations. all of the metabolites showed antimicrobial acitivity
several toxic to sea urchin sperm at very low concentrations
all compounds toxic to sea urchin larvae within 24 hours and several
active at very low (1 x 10-7M) concentration majority were toxic to fish within 1 hour
at concentrations as low as 5micrograms/ml - compounds not direectly toxic still showed detrimental
effects (sedated beahvior, discoloration, increased respiration)
all showed significant fish feeding deterrence 50% of conchs died within 6 days feeding on Caulerpa caulerpenyne
was 0.35% dry weight (very high levels)"Of the many diverse metabolites
that we and others have isolated from a wider spectrum of marine plnts,
few show the potent activities of these green algal metabolites in these bisassays.
The compounds inhibit the growth of microorganisms, development of fertilzied urchin eggs,
and they are toxic to larval and adult stages of potential herbivores."
Caulerpenyne isolated in varying concentrations from C. taxifolia,
sertularoides, racemosa, mexicana, cuppressoides, prolifera, verticallata, paspaloides, and lanuginosa.
and shows strong toxic and feeding deterrent properties - much of the biological activity of Caulerpa owed tothis compound.
Parrotfish show low survivability when fed Caulerpales- with mortalities attributed to Caulerpa toxins.