Natural antifouling compounds

Price, R.R., Patchen, M., Rittschof, D., Clare, A.S., and Bonaventura, J., Performance enhancement of natural antifouling compounds and their analogs through microencapsulation and controlled release, Biofouling, 6, 207, 1992. 

Qian PY, Xu Y, Fusetani N (2010) Natural products as antifouling compounds recent progress and future perspectives. Biofouling 26 223-234... 

Bugula neritina) and related organisms produce substances with antibacterial, antitumor (e.g. bryostatins, didemnin B, dolastatin, girodazol, halichondrin B), anti-inflammatory (e.g. pseudopterosin E, manoalide derivatives), antifungal, antiviral, or immuno-suppressive (e.g. microcolin A and B) activity [399,400]. These compounds and/or their synthetic derivatives may be important novel bioactive pharmaceutical substances. It is also very Hkely that some new natural marine substances or their derivatives can be used as antifouling compounds, insecticides, or fungicides. 

A considerable number of organometallic species of germanium, tin and lead have been detected in the natural environment. A number of these are nonmethyl compounds which have entered the environment after manufacture and use (e.g. butyltin and phenyltin compounds by diffusion from antifouling paints on boats, and ethylleads from leaded gasoline). Only a few methyl compounds are now manufactured and used (e.g. some methyltin compounds are used as oxide film precursors on glass)1. 

In recent years organotin compounds have been increasingly used in various technological applications that would facilitate their entry into the environment 115, 116). Methyltin compounds have been found in natural waters at very low concentrations, as have butyltin compounds 117-119). The latter probably come from widespread commercial use of butyltin compounds in antifouling paints or agricultural biocades 113, 114, 118). 

When larvae fail to settle in a particular test situation, is it due to the absence of positive cues, or are there other factors that prohibit settlement, even when positive cues may be present This is a difficult question to answer because of the possibility that a negative cue may, in fact, be a neutral substance that simply makes the positive cue undetectable by a larva, rather than a substance that causes a larva to reject a potential settlement site. Much effort to demonstrate negative cues to settlement has come from the search for antifouling natural products from marine organisms (reviewed by Pawlik 3 see also Chapters 10 and 17 in this volume). However, there is little reason to believe that extracted compounds which are toxic or aversive to invertebrate larvae have any such function in nature. The best evidence to date for chemical deterrence of larval settlement comes from the work of Woodin and co-workers.212 214 Focusing on halogenated compounds released by many marine polychaete and enteropneust worms,212 they have shown inhibition of settlement of larvae of other species in the presence of the compounds.213 214... 

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