Project description:Early and mature biofilm formation in the extremely halophilic euryarchaeon Halobacterium salinarum strain R1 was characterized by SWATH-LC/MS/MS. Using a simple surfactant-assisted protein solubilization protocol and one-dimensional ultrahigh performance nanoflow chromatography on the front end, 63.2% and 58.6% of the predicted Hbt. salinarum R1 proteome could be detected and quantified, respectively. Analysis of biophysical protein properties, functional analysis and pathway mapping indicate that we achieved a comprehensive characterization of the proteome. 60.8% of quantified proteins (or 34.5% of the predicted proteome) exhibited significant abundance changes between planktonic and biofilm states, demonstrating that haloarchaeal biofilm formation represents a profound “lifestyle change” on the molecular level. Taken together our results and analysis constitute the first comprehensive study to track the molecular changes from planktonic cells to initial and mature archaeal biofilms on the proteome level. Proteins exemplifying different protein expression level profiles were selected, and their corresponding gene transcripts targeted by qRT-PCR to test the feasibility of establishing rapid PCR-based assays for archaeal biofilm formation.
Project description:Halobacterium salinarum NRC-1 was grown in CM media, at 37oC in a waterbath with agitation of 125 rpm under constant light. Analysis of transcriptional changes during growth, in addition to mapping of transcriptome structure under the same conditions, provided interesting insights about regulatory logic within prokaryotic coding regions.
Project description:Halobacterium salinarum R1 is an extremely halophilic archaeon capable of adhesion and biofilm formation. We have recently shown that living in biofilms facilitates higher cell survival under heavy metal ion stress in this species, while specific rearrangements of the biofilm architecture were observed upon Ni2+ and Cu2+ exposition, respectively. In this study, quantitative analyses were performed by SWATH-LC-MS/MS to determine the respective proteomes under the influences of Ni2+ and Cu2+ in planktonic and biofilm cells. Quantitative data for 1180 proteins were gained, corresponding to 46% of the predicted proteome. In planktonic cells, 234 proteins showed significant abundance changes after metal ion treatment, of which 47% occurred combined in Cu2+ and Ni2+ treated samples. Regarding biofilms, significant changes were detected for 52 proteins. Only three proteins changed under both conditions, suggesting metal-specific stress responses in biofilms.
