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Sinularia polydactyla, a dioecious, abundant soft coral in the South Pacific, exhibits biochemical phenotypic plasticity in secondary metabolite production in relation to predation intensity. However, it is unclear to what extent changes in secondary metabolites, such as 11β- acetoxypukalide, may result from specific, induced pathway activities at the level of gene expression. To investigate both chemical changes and differences in mRNA diversity in response to predation stress, artificial predation experiments were conducted in situ on colonies of S. polydactyla. Multivariate statistical analyses of coral biochemical metabolites and our kinetic transcriptome profiling technique indicate that that the induction of 11γ-acetoxypukalide by predation stress likely results from the upregulation of either one dominant transcript or a very small set of transcripts, indicative of a targeted upregulation rather than a generalized, genetic stress response. Overall, this work establishes a routine method for integrating high-throughput transcriptome and metabolome data sets to allow for the identification of metabolites whose intracellular concentrations can be readily linked to gene expression events in response to specific treatments in non-model organisms. [ABSTRACT FROM AUTHOR]

Horseshoe crabs, Limulus polyphemus, are the preferred bait in the eel and conch fisheries along the east coast of the United States. However, recent management measures have restricted the availability of horseshoe crabs to commercial fisheries, creating the need for sustainable, alternative bait sources. In this study, we examined the chemistry underlying the predator-prey attraction to determine if specific, isolable attractant metabolites from the horseshoe crab could be identified and characterized for incorporation into an artificial bait. Initial assays with the mud snail, Ilyanassa obsoleta, suggested that the chemoattractants were concentrated in L. polyphemus eggs. Chemical analyses and biological assays of the egg extract indicated the primary cue was a heat-stable, proteinaceous compound (>10 kDa). A carbohydrate-rich fraction of low molecular mass (< 10 kDa) also enhanced mud snail chemotaxis. Analysis of egg digests with SDS-PAGE confirmed the presence of glycoproteins or carbohydrate-binding proteins in the horseshoe crab egg extract. Because the attractant appears to be a complex protein or glycoprotein, conventional chemical synthesis is unlikely. However, the tools of modern biotechnology offer the potential to produce this attractant in a system independent of the horseshoe crab. Such an attractant could be incorporated into an artificial bait, providing an ecologically sound alternative for commercial eel and whelk fisheries. [ABSTRACT FROM AUTHOR]

Since chemical ecology emerged as a field of marine science, it has been strongly influenced by studies of chemically mediated interactions in landbased systems. Marine chemical ecologists, like their terrestrial counterparts, initially focused on identifying natural products and evaluating the potential ecological roles of these products as defenses, attractants, or other cues. Now, like our land-based colleagues, we must increase our focus on the physiological and biochemical mechanisms that underlie the chemical interactions, paying particular attention to regulation of biosynthetic pathways, within-plant and betweenplant signaling cues, and comparative and functional genomics. Here, we review the current state of knowledge regarding a heterogenous group of macrophyte natural products, the marine tannins and simple phenolics, to illustrate how such information is critical to future attempts to predict their ecological roles. [ABSTRACT FROM AUTHOR]

The plant growth regulators jasmonic acid and methyl jasmonate (MeJA) have recently been identified in a variety of marine algae; however, their role in these organisms is currently unknown. Here we report that exposure to MeJA, during periods of tidal emergence causes the induction of polyphenolic chemical defenses (the phlorotannins) in two populations of the common rockweed Fucus vesiculosus (Linnaeus). Phlorotannin concentrations were up to 1.6 times higher in the growing apices of F. vesiculosus from both Avery Point (Connecticut, USA) and Roosevelt Inlet (Delaware, USA) within 10–14 days after a single brief exposure to airborne MeJA at concentrations ranging from 5.42 to 542 nM. The timing and magnitude of this induced increase in phlorotannin concentration are similar to that caused by real and simulated herbivory, raising the question of whether jasmonates, or their oxylipin relatives, are natural elements of antiherbivore responses in Fucus, as they are in vascular plants. [ABSTRACT FROM AUTHOR]

Focuses on the chemical characteristics, functions, variability and potential cost in both temperate and tropical marine systems of phlorotannins, polyphenolic brown algal secondary metabolites that can function as herbivore deterrents, digestive inhibitors and antibacterial agents. Classes of polyphenolics; Categories of phlorotannins based on the type of structural linkages that result from the polymerization process and on the number of hydroxyl groups.

Two bioassays (fish mortality and fish erythrocyte hemolysis) were used to survey for the presence of toxic principles in aqueous extracts of 19 species of marine macroalgae found in south Florida coastal waters. Extracts from six species (Chlorophyta -- Anadyomene stellata (Wulfen) C. Ag., Caulerpa prolifera (Forsskaål) Lamour.,. Penicillus capitatus Lamarck: Rhodophyta --Centrocer-as clavulatum (C. Ag.) Montagne, Laurencia papillosa (Forsskaål) Grev., L. poitel (Lamour.) Howe) showed lethal toxicity to the spotfin majarra. Euconistomus argenteus Baird & Girard. Extracts from three species (Chlorophyta -- A. stellata: Phacophyta -- Dictyota dichotoma (Hudson) Lamour Rhodophyta -- Wrangelia penicillata C. Ag.) lysed erythrocytes of sea bream, Archosargus rhomboidalis (L.). [ABSTRACT FROM AUTHOR]

Studies the effects of polyphenolic compounds on the digestion and assimilation of fish herbivores Xiphister mucosus. Reduction of assimilation efficiency; Effects of phlorotannin molecular size; Ecological relevance of the finding; Completion of phlorotannin molecular size profiles; Bioactivity of polyphenolics.

Studies the responses of Strombus gigas larvae to chemical cues, with focus on biology. Concentration dependency and optimal exposure time of aqueous extracts of Laurencia poitei; Behavioral and gross morphological changes occurring in conch larvae; Effects of molecular weight compounds on conch larvae metamorphosis; Importance of chemical cues.