Environmental effects on arsenosugars and arsenolipids in Ectocarpus (Phaeophyta)
Seaweeds have recently been shown to contain a significant proportion of arsenic in the form of arsenolipids (AsLp) Three strains of the filamentous brown alga Ectocarpus species were grown in the laboratory with different simulationsofenvironmentalstress:controlconditions(1/2Provasoli enrichedseawater),lownitrate(30%oftheamount ofnitratesinthecontrol),lowphosphate(30%ofthe amountofphosphateinthecontrol)andunderoxidativestresslevels (2 mM H2O2) Generally, the major AsLp was an arsenic containing hydrocarbon, AsHC360 (50 80% but additionally, several arsenic containing phospholipids (AsPL) were identified and quantified using high performance liquid chroma tography inductivelycoupledplasmamassspectrometryandelectrosprayionisationmassspectrometry(HPLC ICP MS/ ESI MS).TheAsLpsincultureswerecomparedwithAsLpsinEctocarpusfoundinitsnaturalhabitataswellaswithother brown filamentous algae. The AsLp and arsenosugar profiles differed depending on the experimental conditions. Under low phosphate conditions, a significant reduction of phosphorus containing arsenosugars was noticed, and a significant increaseofphosphate containingAsLpswasfoundwhencomparedwiththecontrols.Strainsgrownunderoxidativestress showed a significant increase in AsLps as well as clear physiological changes. Additional keywords: chloroplasts, cultures, HPLC ESIMS, HPLC ICP MS, lipid soluble arsenic, speciation. Received 25 October 2014, accepted 2 March 2015, published online 28 July 2015