Increased potential for wound activated production of Prostaglandin E and related toxic compounds in non-native populations of Gracilaria vermiculophylla.

The capacity of the East Asian seaweed Gracilaria vermiculophylla ("Ogonori") for production of prostaglandin E from arachidonic acid occasionally causes food poisoning after ingestion. During the last two decades the alga has been introduced to Europe and North America. Non-native populations have been shown to be generally less palatable to marine herbivores than native populations.

Defence chemistry modulation by light and temperature shifts and the resulting effects on associated epibacteria of Fucus vesiculosus.

The goals of this study were (1) to investigate whether Fucus vesiculosus regulates the production of its antifouling defence chemicals against epibacteria in response to light limitation and temperature shifts and (2) to investigate if different surface concentrations of defence compounds shape epibacterial communities. F. vesiculosus was incubated in indoor mesocosms at five different temperature conditions (5 to 25°C) and in outdoor mesocosms under six differently reduced sunlight conditions (0 to 100%), respectively.

De novo analysis of electron impact mass spectra using fragmentation trees.

The automated fragmentation analysis of high resolution EI mass spectra based on a fragmentation tree algorithm is introduced. Fragmentation trees are constructed from EI spectra by automated signal extraction and evaluation. These trees explain relevant fragmentation reactions and assign molecular formulas to fragments.

Conserved and species-specific oxylipin pathways in the wound-activated chemical defense of the noninvasive red alga Gracilaria chilensis and the invasive Gracilaria vermiculophylla.

Chemical defense of the invasive red alga Gracilaria vermiculophylla has been studied and compared to that of the noninvasive but related Gracilaria chilensis. Both species rely on a wound-activated chemical defense that makes them less attractive to the herbivorous sea snail Echinolittorina peruviana. The chemical stress response of both species was monitored by LC-ESIMS-based metabolic profiling and revealed commonalities and differences.

Metabolomic assessment of induced and activated chemical defence in the invasive red alga Gracilaria vermiculophylla.

In comparison with terrestrial plants the mechanistic knowledge of chemical defences is poor for marine macroalgae. This restricts our understanding in the chemically mediated interactions that take place between algae and other organisms. Technical advances such as metabolomics, however, enable new approaches towards the characterisation of the chemically mediated interactions of organisms with their environment.

Survey of volatile oxylipins and their biosynthetic precursors in bryophytes.

Oxylipins are metabolites which are derived from the oxidative fragmentation of polyunsaturated fatty acids. These metabolites play central roles in plant hormonal regulation and defense. Here we survey the production of volatile oxylipins in bryophytes and report the production of a high structural variety of C5, C6, C8 and C9 volatiles of mosses.