Bacterial 'cell-cell talk' in complex microbial communities: identifying diverse and novel quorum sensing signals in extreme environments
EMSL Project ID
51876
Abstract
Microbes communicate using quorum sensing (QS), a type of cell-cell signaling that occurs within and among species of microbes, and even between kingdoms, to synchronize their gene expression and adaptive responses to stress. The best studied form of QS is based on the signaling molecule N-acyl homoserine lactone (AHL), a neutral lipid, containing a lactone ring, various carbon-length chains, and R-groups. To date, there are ~ 24 AHL molecules that have been identified from cultured isolates, but a handful of recent studies using high resolution mass spectrometry (MS) methods have found 20+ AHLs being produced by just a single isolate, with several new AHL molecules identified. In addition, AHL-QS systems have now been identified in microbes from open oceans, symbionts of marine sponges, soils, and N-fixing bacteria associated with root nodulation. This suggests that AHL-QS is widespread, and that microbial communities may function more as consortia in natural systems. However, AHL-QS is not well studied in natural systems nor from complex, natural microbial communities. Standard methods used to identify AHLs are limited, and have usually focused on targeted procedures requiring AHL standards. We propose to utilize EMSL's unique lipidomic and metabolic capabilities to identify and characterize novel AHLs and AHL-QS systems from an active steam vent environment, an extreme environment where AHL-QS has not been studied. This microbial community survives in extreme temperatures (41-52 degrees), is exposed to high levels of CO2 and other volcanic gases and contains a high level of deep branching phyla (Archaea, Chlorobi, Chloroflexi) that are relavent to bioenergy-related studies. In combination with transcriptomic and metagenomic data already gathered from these samples, we will: (A) use a combination of EMSL tools to develop and employ a high resolution mass spectrometry methods to discover novel-AHLs from these natural systems, (B) understand how AHL-QS systems of complex microbial communities with deep branching phyla change under environmental stress, and (C) begin to address the present knowledge gap of AHL-QS in complex natural microbial systems and extreme environments. This proposal is relevant to the DOE BER overall mission, under Biological Systems Science Division, which seeks to "understand intra- and inter-cellular microbial (archaeal, bacterial, fungal) systems, and their functioning within the immediate surrounding environment using molecular, genomic and other -omic approaches...". The unique capabilities at EMSL are required to determine potentially novel AHLs, and how their relative concentrations change to environmental stressors. Although lipids cannot be fully integrated with transcriptomic data yet, data from these multi-omic sources can be used to identify AHL-QS systems that are active in these unique communities. Working with Jennifer Kyle (EMSL), nine of these samples were evaluated for lipidomic profiles previously, and we detected at least 10 different potentially novel AHLs present through identification of lactone ring diagnostic m/z ratio.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2021-10-01
End Date
2023-10-01
Status
Closed
Released Data Link
Team
Principal Investigator
Co-Investigator(s)