Thesis
An infrared chemical analysis of EPS produced during growth of cyanobacterial-heterotroph multi-species biofilms
Washington State University
Master of Science (MS), Washington State University
2017
Handle:
https://hdl.handle.net/2376/101795
Abstract
Multiple stable unicyanobacterial consortia (UCC) containing one phototrophic bacteria and multiple heterotrophic bacteria have been isolated from a saline (epsomitic) microbial mat. In the UCCs, the phototrophic cyanobacteria provide the only source of fixed carbon. Two UCCs are the focus of studies to identify mechanisms that control the flow of energy and materials through microbial communities. We hypothesize that components of the extracellular polymeric substance (EPS) produced by the cyanobacteria provide fixed carbon to the heterotrophic community members and thus EPS is a key regulator of phototroph-heterotroph interactions. To test this, we developed an extraction protocol to remove two operational fractions of UCC EPS (bound- and loosely associated- EPS [bEPS and laEPS, respectively]) and simplified one UCC to a community of a single phototroph and three heterotrophs. A 28-day temporal study of EPS was collected from both UCCs to determine changes in EPS composition during biofilm assembly and succession. The chemical components of the purified EPS fractions were evaluated using attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy analysis to determine the relative abundances of lipids, protein, sugars, and nucleic acids in EPS fractions across all time points. Temporal changes in the amounts of proteins and lipids were observed in EPS fractions as the UCCs matured. Interestingly, the relative abundances of sugars in the EPS fractions remained stable during the temporal study, possibly suggesting that nascent polysaccharides were quickly consumed. Comparison of a UCC to the simplified UCC reveals specific polysaccharide and lipid peaks attributed to either the phototroph or heterotroph. Principle component analysis (PCA) was used to reveal the biological molecules showing changes across samples from the two UCC cultures and resolve temporal- and EPS fraction-dependent chemical differences, furthering our understanding of how the EPS matrix influences phototroph-heterotroph interactions in a microbial mat community.
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Details
- Title
- An infrared chemical analysis of EPS produced during growth of cyanobacterial-heterotroph multi-species biofilms
- Creators
- Abigail Elizabeth Tucker
- Contributors
- Allan S. Felsot (Degree Supervisor)
- Awarding Institution
- Washington State University
- Academic Unit
- Environment, School of the (CAHNRS)
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Identifiers
- 99900525194601842
- Language
- English
- Resource Type
- Thesis