Biofilm formation in the thermoacidophilic crenarchaea Sulfolobus spp.

In this study, the first analysis of crenarchaeal biofilm was performed. Furthermore, this work represents the first in-depth investigation of archaeal biofilm at all. Methods for the analysis of hyperthermophilic biofilm were developed, for instance, microtiter assay, CLSM, and detection of biofilm...

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Bibliographic Details
Main Author: Koerdt, Andrea
Contributors: Albers, Sonja V. (Dr.) (Thesis advisor)
Format: Doctoral Thesis
Language:English
Published: Philipps-Universität Marburg 2011
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Summary:In this study, the first analysis of crenarchaeal biofilm was performed. Furthermore, this work represents the first in-depth investigation of archaeal biofilm at all. Methods for the analysis of hyperthermophilic biofilm were developed, for instance, microtiter assay, CLSM, and detection of biofilm by fluorescent probes. Furthermore, it was shown that the three related strains S. solfataricus, S. acidocaldarius and S. tokodaii exhibit a high number of differences related to the architecture (carpet-like ranging to tower-like structures), protein and expression pattern, and the requirement of surface appendages. It was revealed that the matrix of biofilm contains a high amount of sugars (mannose, glucose, N-acetyl-D-glucosamine and galactosyl residues), while it is still unclear if these sugars are present in the exopolysaccharides, glycosylated proteins or both. Furthermore, the matrix included low levels eDNA which are not important for the stability and structure of the biofilm. Remarkable was the fact that the strains showed different reactions when they were exposed to stressful conditions (temperature, pH, and iron). Commonly required genes/proteins in all three Sulfolobus ssp. included Lrs14-like transcriptional regulators and FabG, which could be involved in a novel-archaea quorum sensing system. Another interesting aspect considered the impact of surface appendages to attachment and biofilm formation. S. solfataricus requires the flagella and the Ups-pili for surface attachment, but they seemed to be less important for biofilm formation. In contrast, S. acidocaldarius exhibited differences in surface attachment dependent on the presence of surface structures, while at least two appendages needed to be deleted before a significant reduction of attachment could be observed. The exception was the mutant which exhibited just the Aap-pili and had a higher affinity to the surface (150% increased). Additionally, the architecture of the biofilm changed in dependency on the appendages as well (three distinct phenotypes were observed). Furthermore, it was also possible to adapt a GFP usable for the study of biofilm formation in S. acidocaldarius. Finally, in vivo analyses of the expression of Ssα-man discovered the involvement in the sugar modification of the EPS in S. solfataricus. The result of this study indicated the possibility that glycan trimming might be existent in Sulfolobus spp.
DOI:10.17192/z2011.0647