© 2000 by The Society for Integrative and Comparative Biology
Book Reviews
1 Department of Biological Sciences, Universtiy of Iowa, Iowa City, Iowa 52242
Eicosanoids in Invertebrate Signal Transduction Systems. DAVID W. STANLEY. Princeton University Press, Princeton, New Jersey, 2000. 277 pp., species and subject indexes, $47.50 (ISBN 0-69100660-1 cloth).
This flawed volume pulls together scattered data and usefully sums up what is known about the occurrence, metabolism and physiological effects of eicosanoids in invertebrate animals. Eicosanoids are biologically active metabolites of 20-carbon polyunsaturated fatty acids such as, especially, arachidonic acid. They are of extraordinary current interest to physiologists and the pharmaceutical industry since they include the prostaglandins, lipoxins, and leukotrienes, known in mammalian systems to regulate a host of physiologies including, vasomotor action, reproduction, hormone secretion, inflammatory processes and the immune system. The book explains eicosanoid chemistry and biosynthesis, although the arcane symbolic shorthand used for the fatty acids and derivatives is not interpreted for us. There follow several chapters, grouped as eicosanoids in invertebrate reproduction, immunity, ion transport, temperature preference, development, and "ecology." The last includes predator avoidance and parasite–host interactions. Eicosanoids have been identified, often rigorously, in virtually all major invertebrate taxa. The evidence is strong, although mostly indirect, that eicosanoids mediate some extraordinary physiologies. Among the more well-documented is the transfer of enzyme activity by male crickets to female reproductive tracts which then biosynthesize prostaglandins that in turn induce egg-laying; certain corals contain the highest known concentrations of prostaglandins, apparently an adaptive predator-avoidance strategy; several eicosanoids synthesized by endoparasites apparently blunt host immune reactions. Critical assessment and syntheses are attempted, but the whole is marred by the author's insistence upon reciting the entire history of a given laboratory's contributions, regardless of whether findings and conclusions are progressively modified with new data that supersede the old. This is accompanied by dreary detailing of methods that are standard, trivial or have no important bearing on the message.
The rest of the book can safely be ignored, starting with the title. (Incidentally, in Acknowledgments, the names of two of the readers are misspelled.) Of course I was attracted by "signal transduction." Keep in mind that this expression refers mainly to the energy transfer that occurs between a receptor (occupied by a specific ligand) and a transducing protein that ends in activating a membrane-bound enzyme or nuclear protein. The result usually is generation of one or more signaling compounds (second messengers) that regulate the cell, ultimately via the nucleus. Turning instantly to a concluding section entitled, "How eicosanoids work," I was informed that essentially nothing is known about mechanisms of action of eicosanoids in invertebrates. There are two reports of evidence that eicosanoids are receptor ligands, and that is the extent of it. In short, this book has nothing to do with signal transduction in invertebrates. (Other fashionable terms inappropriately used: "up-down-regulate," "probe," "model.") The only studies I could find that indicate eicosanoid metabolites act intracellularly as downstream signals were those of Piomelli et al.; these metabolites were shown to mediate synaptic modulation in Aplysia (species not indexed). This evidence was simply mentioned in a sentence and not discussed.
The author routinely gets into trouble when he departs from straight reporting. Investigators are warned repeatedly not to expect that physiological systems in invertebrates vis-a-vis eicosanoids are the same as those in the mammalian "model"! A "theory" by the author (the "biological paradigm") urges in essence that we reverse the usual approach in understanding physiological processes in favor of a fishing expedition in which we first look for eicosanoids and then find out what they do. The obvious is belabored with depressing frequency; the following passage illustrates this and other problems:
"Compared to our understanding of eicosanoids in invertebrates, the published literature on the operative picture of eicosanoid actions in mammals is far ahead. To be sure, the first research on eicosanoids in mammals predates work on invertebrates by almost four decades, and a substantial head start would rather naturally put the work on mammals somewhat ahead of other work. The lengthy lead, however, is not so long as it seems. For many of these forty years, technical barriers, such as the very limited availability of chemicals, slowed all progress. It seems to me that something else is responsible for the tremendous gap between progress in our understanding of eicosanoids in mammals and progress in invertebrate systems.–"
Dr. Stanley goes on to conclude that progress was faster in mammals because of interest in human biology and medicine! This work should never have been published without serious editorial scrutiny. In that event, it would have been reduced to at least half its volume and would more suitably have been published as a journal review.
CiteULike 
Connotea 
Del.icio.us What's this?
| ||||||||||||||||||||||||||||||||||||||||||||||