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Title: Changes in the Structure of the Microbial Community Associated with Nannochloropsis salina following Treatments with Antibiotics and Bioactive Compounds

Open microalgae cultures host a myriad of bacteria, creating a complex system of interacting species that influence algal growth and health. Many algal microbiota studies have been conducted to determine the relative importance of bacterial taxa to algal culture health and physiological states, but these studies have not characterized the interspecies relationships in the microbial communities. Here we subjected Nanochroloropsis salina cultures to multiple chemical treatments (antibiotics and quorum sensing compounds) and obtained dense time-series data on changes to the microbial community using 16S gene amplicon metagenomic sequencing (21,029,577 reads for 23 samples) to measure microbial taxa-taxa abundance correlations. Short-term treatment with antibiotics resulted in substantially larger shifts in the microbiota structure compared to changes observed following treatment with signaling compounds and glucose. We also calculated operational taxonomic unit (OTU) associations and generated OTU correlation networks to provide an overview of possible bacterial OTU interactions. This analysis identified five major cohesive modules of microbiota with similar co-abundance profiles across different chemical treatments. The Eigengenes of OTU modules were examined for correlation with different external treatment factors. This correlation-based analysis revealed that culture age (time) and treatment types have primary effects on forming network modules and shaping the community structure. Additionalmore » network analysis detected Alteromonadeles and Alphaproteobacteria as having the highest centrality, suggesting these species are “keystone” OTUs in the microbial community. Furthermore, we illustrated that the chemical tropodithietic acid, which is secreted by several species in the Alphaproteobacteria taxon, is able to drastically change the structure of the microbiota within 3 h. Lastly, taken together, these results provide valuable insights into the structure of the microbiota associated with N. salina cultures and how these structures change in response to chemical perturbations.« less
 [1] ;  [2] ;  [1] ;  [2] ;  [3]
  1. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Dept. of Systems Biology
  2. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Dept. of Biomass Science and Conversion Technology
  3. Sandia National Lab. (SNL-CA), Livermore, CA (United States). Dept. of Systems Biology; Univ. of the Philippines Diliman, Quezon City (Philippines). Inst. of Chemistry
Publication Date:
OSTI Identifier:
Report Number(s):
Journal ID: ISSN 1664-302X; 646174
Grant/Contract Number:
AC04-94AL85000; SCW1039
Accepted Manuscript
Journal Name:
Frontiers in Microbiology
Additional Journal Information:
Journal Volume: 7; Journal ID: ISSN 1664-302X
Frontiers Research Foundation
Research Org:
Sandia National Laboratories (SNL-CA), Livermore, CA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
59 BASIC BIOLOGICAL SCIENCES correlation network; microbiota; algae