Chemical cues induce consumer-specific defenses in a bloom-forming marine phytoplankton.

Blooms of the phytoplankton Phaeocystis can comprise 85% of total production and generate major biogeochemical signals across broad oceanic regions. The success of Phaeocystis may result from its ability to change size by many orders of magnitude when it shifts from small cells of 4-6 microm to large colonies of up to 30,000 microm in diameter. Single cells are consumed by ciliates but not copepods, whereas colonies are consumed by copepods but not ciliates.

The Bogorol family of antibiotics: template-based structure elucidation and a new approach to positioning enantiomeric pairs of amino acids.

The sequence positions of d and l Leu and Lys residues in bogorol A (1) have been defined by a simple and novel approach that utilizes small amounts of sample and focuses on detecting the order in which amino acids are liberated from the parent peptide during acid-catalyzed hydrolysis. This technique builds on a previously established relationship between the steric and electronic features of amino acids and their predilection for acidic liberation from polypeptides via dipeptides. The results, which complete the structure of bogorol A, have been confirmed by traditional degradation experiments.

Drug discovery and sea hares: bigger is better.

Traditionally, small molecules (<1kDa) have dominated the study of the chemistry and chemical ecology of marine natural products. However, as reported in a recent publication, Yang and co-workers have isolated a 60-kDa antibacterial protein from the defensive secretions of the sea hare Aplysia californica. This protein, escapin, has been characterized as an l-amino acid oxidase with bacteriostatic and bacteriocidal activities.

Isolation and structure elucidation of feeding deterrent diterpenoids from the sea pansy, Renilla reniformis.

Four new briarane diterpenoids, renillins A-D (1-4), and the known compound renillafoulin C (5) were isolated from the sea pansy, Renilla reniformis. The structures and relative stereochemistry were elucidated by the interpretation of spectroscopic data. Using laboratory feeding assays, all compounds tested at natural concentrations significantly deterred feeding by the predatory lesser blue crab, Callinectes similis, while renillins C (3) and D (4) also deterred feeding by the predatory mummichog fish, Fundulus heteroclitus.

Defensive 2-alkylpyrrole sulfamates from the marine annelid Cirriformia tentaculata.

Three novel 2-alkylpyrrole sulfamates (1-3) were isolated from the marine worm Cirriformia tentaculata. The structures were elucidated by the interpretation of spectral data obtained on inseparable mixtures of the unstable compounds. This suite of metabolites deterred feeding by the generalist predatory fish Thalassoma bifasciatum.

Tupuseleiamides and basiliskamides, new acyldipeptides and antifungal polyketides produced in culture by a Bacillus laterosporus isolate obtained from a tropical marine habitat.

Laboratory cultures of PNG 276, a Bacillus laterosporus isolate obtained from coastal waters off Papua New Guinea, have been shown to produce the novel metabolites basiliskamide A (1), basiliskamide B (2), tupuseleiamide A (3), and tupusleiamide B (4). The structures of 1 to 4 were elucidated by analysis of spectroscopic data and chemical degradation. Basiliskamides A (1) and B (2) show potent in vitro anti-Candida activity.