Global metabolome analysis of Dunaliella tertiolecta, Phaeobacter italicus R11 Co-cultures using thermal desorption - Comprehensive two-dimensional gas chromatography - Time-of-flight mass spectrometry (TD-GC×GC-TOFMS)

Dunaliella tertiolecta is a marine microalgae that has been studied extensively as a potential carbon-neutral biofuel source (Tang et al., 2011). Microalgae oil contains high quantities of energy-rich fatty acids and lipids, but is not yet commercially viable as an alternative fuel. Carefully optimised growth conditions, and more recently, algal-bacterial co-cultures have been explored as a way of improving the yield of D. tertiolecta microalgae oils. The relationship between the host microalgae and bacterial co-cultures is currently poorly understood. Here, a complete workflow is proposed to analyse the global metabolomic profile of co-cultured D. tertiolectra and Phaeobacter italicus R11, which will enable researchers to explore the chemical nature of this relationship in more detail. To the best of the authors' knowledge this study is one of the first of its kind, in which a pipeline for an entirely untargeted analysis of the algal metabolome is proposed using a practical sample preparation, introduction, and data analysis routine.

Unravelling the polydopamine mystery: is the end in sight?

Mass spectroscopic studies using deuterium-labeling reveal a novel structure for polydopamine, deriving from dopaminochrome and uncyclized dopamine.

Uptake and biotransformation of 6,7-dimethylquinoline and 6,8-dimethylquinoline by rainbow trout (Salmo gairdneri)

1. 6,7-Dimethylquinoline (6,7-DMQ) is readily taken up by rainbow trout and bioconcentrated in tissue after exposure to ca 1 mg/l for 7.5 h. Mean bioconcentration factors (from water) were 21, 18, 6 and 14 for bile, liver, muscle and carcass respectively. Mean tissue concentrations after 69-96 h depuration were ND, ND, 0.54 and 0.48 micrograms/g for bile, liver, muscle and carcass respectively. 2. Major metabolites, following exposure to 6,7-DMQ, were conjugates (glucuronide or sulphate) of 7-hydroxymethyl-6-methylquinoline and 6-hydroxymethyl-7-methylquinoline. Mean concentration of metabolites in the bile were 500 micrograms/g after 7.5 h exposure to ca 1 mg/l and 1367 micrograms/g after 9.5 h exposure to ca 1 mg/l and 69 h depuration. 3. 6,8-Dimethylquinoline (6,8-DMQ) is also readily bioconcentrated in fish tissue after exposure to ca 1 mg/l. Mean bioconcentration factors (from water) were 23, 20, 13 and 25 for bile, liver, muscle and carcass respectively. Mean tissue concentrations after 7 h exposure to ca 1 mg/l and 63 h depuration were 4.0, 0.67, 0.49, and 3.2 micrograms/g respectively for bile, liver, muscle and carcass. 4. Major metabolites, following exposure to 6,8-DMQ were conjugates (glucuronide or sulphate) of 6,8-dimethyl-5-hydroxyquinoline, 6,8-dimethyl-7-hydroxyquinoline, 6,8-dimethyl-3-hydroxyquinoline and 6-hydroxymethyl-8-methylquinoline. Mean concentration of metabolites in the bile were 1278 micrograms/g after exposure to ca 1 mg/l for 8 h and 1031 micrograms/g after exposure to ca 1 mg/l for 7 h and 63 h depuration.