PNNL

Abstract

Bacteria-produced quorum sensing signals N-acyl homoserine lactones (AHLs) are found to play an important role in the development of diatom-biofilm (Cylindrotheca sp.) in this study. AHLs promote the growth of diatom and the secretion of extracellular polymeric substances (EPS) as the main biofilm components. Our new results show that AHLs facilitate the diatom-biofilm formation and their effects depend on the length of carbon chains, combining with the analysis of alcian blue staining and scanning electron microscopy (SEM). Confocal laser scanning microscopy (CLSM) demonstrates that AHLs alter the three-dimensional (3D) structures of the diatom-biofilm, increasing the biofilm thickness and the fluorescence intensity. Further, time-of-flight secondary ion mass spectrometry (ToF-SIMS) imaging verifies that EPS contents in the diatom-biofilm increase as a result of exposure to AHLs. This study provides a collection of new experimental evidence of the interaction between bacteria and microalgae in fouling biofilms.