Thallusin Quantification in Marine Bacteria and Algae Cultures

Abstract

Thallusin, a highly biologically active, phytohormone-like and bacterial compound-inducing morphogenesis of the green tide-forming macroalga Ulva (Chlorophyta), was determined in bacteria and algae cultures. A sensitive and selective method was developed for quantification based on ultra-high-performance liquid chromatography coupled with electrospray ionization and a high-resolution mass spectrometer. Upon C18 solid phase extraction of the water samples, thallusin was derivatized with iodomethane to inhibit the formation of Fe–thallusin complexes interfering with the chromatographic separation. The concentration of thallusin was quantified during the relevant phases of the bacterial growth of Maribacter spp., ranging from 0.16 ± 0.01 amol cell−1 (at the peak of the exponential growth phase) to 0.86 ± 0.13 amol cell−1 (late stationary phase), indicating its accumulation in the growth medium. Finally, we directly determined the concentration of thallusin in algal culture to validate our approach for monitoring applications. Detection and quantification limits of 2.5 and 7.4 pmol L−1, respectively, were reached, which allow for quantifying ecologically relevant thallusin concentrations. Our approach will enable the surveying of thallusin in culture and in nature and will thus contribute to the chemical monitoring of aquaculture.

Enantioselective Total Synthesis of the Morphogen (−)‐Thallusin and Mediated Uptake of Fe(III) into the Green Seaweed Ulva

“…However, ee determinations of polar compounds that form metal ion complexes may be problematic. To develop a reliable HPLC‐based method for ee determination of thallusin samples, we adapted our derivatization‐based workflow for thallusin analytics [49] . A first ee determination was undertaken with (−)‐thallusin samples taken from the synthesis described before.…”

“…To develop a reliable HPLC-based method for ee determination of thallusin samples, we adapted our derivatization-based workflow for thallusin analytics. [49] A first ee determination was undertaken with (À )-thallusin samples taken from the synthesis described before. After derivatization with iodomethane, the thallusin methyl ester enantiomers were separated on a chiral amylose column with a proper resolution factor (R = 2.6, Figure 1).…”

Isolation of sulfonosphingolipids from the rosette-inducing bacterium Zobellia uliginosa and evaluation of their rosette-inducing activity

“…Intriguingly, sulfonosphingolipid concentrations were below detection levels in rosette-inducing supernatant extracts supporting our hypothesis, that other yet unknown bacterial-derived metabolites might be the actual morphogens. A targeted MS-analysis of enriched and semi-purified fractions also revealed that neither sphingolipids, capnine bases, siderophores, nor the algae morphogen thallusin 26 were detectable within the active metabolite fractions leaving the chemical nature of the morphogen elusive.…”

Enantioselective Total Synthesis of the Morphogen (‒)-Thallusin and Uptake of its Fe(III) Complex into the Green Seaweed Ulva

“…To develop a reliable HPLC-based method for ee determination of thallusin samples, we employed our recently published derivatization-based workflow. [39] A first determination was undertaken with (-)-thallusin samples from the described synthesis. After methylation with iodomethane, the thallusin ester enantiomers were separated on a chiral amylose column with a proper resolution factor (R = 2.6, Fig.…”