The Isolation of Biologically Active Secondary Metabolites from New Zealand Marine Organisms

<p>An improved protocol for the screening of marine sponges using cyclic loading, PSDVB, and both 1D and 2D NMR spectroscopy is described. Using this new methodology, 51 sponges were screened. Further investigations were carried out on seven of the 51 organisms, resulting in the isolation of several known and eight novel compounds. Clathriols A (32) and B (33) are novel sterols isolated from the sponge Clathria lissosclera. Both 32 and 33 possess the rare 14 Beta stereochemistry, a feature only naturally occurring in marine sponges. Both are also moderate anti-inflammatory compounds. Ten spongian diterpenes were isolated from the New Zealand, sponge Chelonaplysilla violacea, six of which are novel. Cadlinolides C (138) and D (139) are similar to several previously reported compounds while pourewic acid A (140), 15-methoxypourewic acid B (141), methylpourewate B (142) and pourewanone (143) have unique structural features and are of biogenetic significance. Pourewanone (143) is the first example of a formate isolated from the marine environment. Several of the novel diterpenes exhibit moderate anti-inflammatory activity. A potent dinoflagellate toxin was partially purified from cultures of the producing organism, Karenia brevisulcata. K. brevisulcata is a new dinoflagellate species implicated in a large toxic algal bloom in Wellington Harbour, New Zealand, which formed during the summer of 1997/1998. Although the toxin could not be identified, some of the functionality present, and several possible substructures, is proposed. The biological activity of the toxin is also described.</p>

The Isolation of Biologically Active Secondary Metabolites from New Zealand Marine Organisms

<p>An improved protocol for the screening of marine sponges using cyclic loading, PSDVB, and both 1D and 2D NMR spectroscopy is described. Using this new methodology, 51 sponges were screened. Further investigations were carried out on seven of the 51 organisms, resulting in the isolation of several known and eight novel compounds. Clathriols A (32) and B (33) are novel sterols isolated from the sponge Clathria lissosclera. Both 32 and 33 possess the rare 14 Beta stereochemistry, a feature only naturally occurring in marine sponges. Both are also moderate anti-inflammatory compounds. Ten spongian diterpenes were isolated from the New Zealand, sponge Chelonaplysilla violacea, six of which are novel. Cadlinolides C (138) and D (139) are similar to several previously reported compounds while pourewic acid A (140), 15-methoxypourewic acid B (141), methylpourewate B (142) and pourewanone (143) have unique structural features and are of biogenetic significance. Pourewanone (143) is the first example of a formate isolated from the marine environment. Several of the novel diterpenes exhibit moderate anti-inflammatory activity. A potent dinoflagellate toxin was partially purified from cultures of the producing organism, Karenia brevisulcata. K. brevisulcata is a new dinoflagellate species implicated in a large toxic algal bloom in Wellington Harbour, New Zealand, which formed during the summer of 1997/1998. Although the toxin could not be identified, some of the functionality present, and several possible substructures, is proposed. The biological activity of the toxin is also described.</p>

The importance of making testable predictions: A cautionary tale

We found a startling correlation (Pearson ρ > 0.97) between a single event in daily sea surface temperatures each spring, and peak fish egg abundance measurements the following summer, in 7 years of approximately weekly fish egg abundance data collected at Scripps Pier in La Jolla California. Even more surprising was that this event-based result persisted despite the large and variable number of fish species involved (up to 46), and the large and variable time interval between trigger and response (up to ~3 months). To mitigate potential over-fitting, we made an out-of-sample prediction beyond the publication process for the peak summer egg abundance observed at Scripps Pier in 2020 (available on bioRxiv). During peer-review, the prediction failed, and while it would be tempting to explain this away as a result of the record-breaking toxic algal bloom that occurred during the spring (9x higher concentration of dinoflagellates than ever previously recorded), a re-examination of our methodology revealed a potential source of over-fitting that had not been evaluated for robustness. This cautionary tale highlights the importance of testable true out-of-sample predictions of future values that cannot (even accidentally) be used in model fitting, and that can therefore catch model assumptions that may otherwise escape notice. We believe that this example can benefit the current push towards ecology as a predictive science and support the notion that predictions should live and die in the public domain, along with the models that made them.