Thallusin Quantification in Marine Bacteria and Algae Cultures.

Area of Science:

• Marine Biology
• Environmental Chemistry
• Analytical Chemistry

Background:

• Thallusin is a biologically active compound produced by bacteria that induces morphogenesis in the macroalga Ulva.
• Understanding thallusin's role is crucial for managing green tides and optimizing aquaculture.
• Accurate quantification methods are needed to study thallusin's environmental impact and distribution.

Purpose of the Study:

• To develop a sensitive and selective method for quantifying thallusin in bacterial and algal cultures.
• To determine thallusin concentrations during different bacterial growth phases.
• To validate the method for monitoring thallusin in aquaculture settings.

Main Methods:

• Ultra-high-performance liquid chromatography coupled with electrospray ionization and high-resolution mass spectrometry (UHPLC-ESI-HRMS).
• C18 solid-phase extraction for sample preparation.
• Derivatization with iodomethane to prevent interference from Fe-thallusin complexes.

Main Results:

• Thallusin concentration in Maribacter spp. cultures ranged from 0.16 ± 0.01 amol cell−1 to 0.86 ± 0.13 amol cell−1.
• Thallusin was observed to accumulate in the bacterial growth medium.
• Detection and quantification limits of 2.5 and 7.4 pmol L−1 were achieved, enabling the measurement of ecologically relevant concentrations.

Conclusions:

• The developed UHPLC-ESI-HRMS method is sensitive and selective for thallusin quantification.
• The study provides insights into thallusin production dynamics during bacterial growth.
• This approach facilitates thallusin surveying in cultures and natural environments, supporting chemical monitoring in aquaculture.