https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

Fatty acids have been used as qualitative markers to trace or confirm predator-prey relationships in the marine environment for more than thirty years. More recently, they have also been used to identify key processes impacting the dynamics of some of the world's major ecosystems. The fatty acid trophic marker (FATM) concept is based on the observation that marine primary producers lay down certain fatty acid patterns that may be transferred conservatively to, and hence can be recognized in, primary consumers. To identify these fatty acid patterns the literature was surveyed and a partial least squares (PLS) regression analysis of the data was performed, validating the specificity of particular microalgal FATM. Microalgal group specific FATM have been traced in various primary consumers, particularly in herbivorous calanoid copepods, which accumulate large lipid reserves, and which dominate the zooplankton biomass in high latitude ecosystems. At higher trophic levels these markers of herbivory are obscured as the degree of carnivory increases, and as the fatty acids originate from a variety of dietary sources. Such differences are highlighted in a PLS regression analysis of fatty acid and fatty alcohol compositional data (the components of wax esters accumulated by many marine organisms) of key Arctic and Antarctic herbivorous, omnivorous and carnivorous copepod species. The analysis emphasizes how calanoid copepods separate from other copepods not only by their content of microalgal group specific FATM, but also by their large content of long-chain monounsaturated fatty acids and alcohols. These monounsaturates have been used to trace and resolve food web relationships in, for example, hyperiid amphipods, euphausiids and fish, which may consume large numbers of calanoid copepods. Results like these are extremely valuable for enabling the discrimination of specific prey species utilized by higher trophic level omnivores and carnivores without the employment of invasive techniques, and thereby for identifying the sources of energetic reserves. A conceptual model of the spatial and temporal dominance of group-specific primary producers, and hence the basic fatty acid patterns available to higher trophic levels is presented. The model is based on stratification, which acts on phytoplankton group dominance through the availability of light and nutrients. It predicts the seasonal and ecosystem specific contribution of diatom and flagellate/microbial loop FATM to food webs as a function of water column stability. Future prospects for the application of FATM in resolving dynamic ecosystem processes are assessed.

Fatty acid trophic markers in the pelagic marine environment.

(2002). The Effects of Harmful Algal Blooms on Aquatic Organisms. Reviews in Fisheries Science: Vol. 10, No. 2, pp. 113-390.

The Effects of Harmful Algal Blooms on Aquatic Organisms

Calyculin A and okadaic acid: inhibitors of protein phosphatase activity

Chemical Synthesis of Natural Product Peptides: Coupling Methods for the Incorporation of Noncoded Amino Acids into Peptides.

Bioactive marine metabolites. Part 16. Calyculin A. A novel antitumor metabolite from the marine sponge Discodermia calyx

Vibrio sp. isolated from a xanthid crab, Atergatis floridus, was cultured, and tetrodotoxin (TTX) and anhydroTTX were indicated to be present in several fractions of the cell extract and the culture medium by reverse phase HPLC. The presence of the C9-base in alkaline hydrolyzates of these fractions was confirmed by GC-MS and UV spectrometry. These results showed the production of TTX and anhydroTTX in the Vibrio sp., thus indicating one of the origins of TTX in nature.

Occurrence of tetrodotoxin and anhydrotetrodotoxin in Vibrio sp. isolated from the intestines of a xanthid crab, Atergatis floridus.

To clarify the mechanism of toxification in animals contaminated with tetrodotoxin, the intestinal contents of the puffer Fugu vermicularis vermicularis were examined for bacterial flora in 1985. Twenty-six out of 33 strains belonged to the genus Vibrio. These bacteria were classified into Groups I to VII, based on biological and biochemical characters. High performance liquid chromatography and gas chromatography-mass spectrometry, together with mouse bioassay for toxicity, clearly demonstrated that Group I produced tetrodotoxin and anhydrotetrodotoxin under cultivation with a medium composed of Phytone peptone (BBL) and NaCl. Some other groups also produced this toxin and/or related substances to some extent. Strains of Group I were all identified as Vibrio alginolyticus. Two strains among four produced a detectable amount of tetrodotoxin and/or anhydrotetrodotoxin, as measured by all instrumental analyses applied. Our findings suggest that some strains of V. alginolyticus are closely related to the toxification of the puffer, and probably of other species.

Kanehisa Hashimoto

Papers

Bioactive marine metabolites. Part 16. Calyculin A. A novel antitumor metabolite from the marine sponge Discodermia calyx

Occurrence of tetrodotoxin and anhydrotetrodotoxin in Vibrio sp. isolated from the intestines of a xanthid crab, Atergatis floridus.

Vibrio alginolyticus, a tetrodotoxin-producing bacterium, in the intestines of the fish Fugu vermicularis vermicularis

Theonellamide F: a novel antifungal bicyclic peptide from a marine sponge Theonella sp.

Kabiramide C, a novel antifungal macrolide from nudibranch eggmasses