Project description:To combat dental implant-associated infections, there is a need for novel materials which effectively inhibit bacterial biofilm formation. In the present study, a titanium surface functionalization based on the “slippery liquid-infused porous surfaces” (SLIPS) principle was analyzed in an oral flow chamber system. The immobilized liquid layer was stable over 13 days of continuous flow. With increasing flow rates, the surface exhibited a significant reduction in attached biofilm of both the oral initial colonizer Streptococcus oralis and an oral multi-species biofilm composed of S. oralis, Actinomyces naeslundii, Veillonella dispar and Porphyromonas gingivalis. Using single cell force spectroscopy, reduced bacterial adhesion forces on the lubricant layer could be measured. Gene expression patterns in biofilms on SLIPS, on control surfaces and planktonic cultures were also compared. For this purpose, the genome of S. oralis strain ATCC® 9811TM was sequenced using PacBio Sequel technology. Even though biofilm cells showed clear changes in gene expression compared to planktonic cells, no differences could be detected between bacteria on SLIPS and on control surfaces. Therefore, it can be concluded that the ability of liquid-infused titanium to repel biofilms is solely due to weakened bacterial adhesion to the underlying liquid interface.
Project description:Transcription profile of Escherichia coli cells in mono-species pure planktonic cultures was compared to that of E. coli cells in E. coli-Stenotrophomonas maltophilia dual-species planktonic cultures E. coli cells were separated from dual-species planktonic cultures before total RNA extraction to eliminate possible cross hybridization from S. maltophilia transcripts. The separation method was developed by combining the use of reagent RNAlater and immuno-magnetic separation. Pure E. coli planktonic cultures were processed with the same separation protocol before RNA extraction.
Project description:The aim of this work was to compare gene expression of wild type, sigG1 and rsfG mutants, to determine the SigG1-dependent genes in Streptomyces
Project description:The goal of this study was to determine how the method of pooling (combining mutants) for bacteral Tn libraries affected mutant distribution. Previously we generated a pooled version of a~6,800 Tn mutant library in Enterococcus faecalis OG1RF by plating and scraping individual mutants. Here, we combined liquid cultures grown in deep well plates. DNA from the new pooled library was extracted, and TnSeq was used to compare mutant distribution between the old (plate scraping) and new (liquid pooling) Tn library formats. This is important because it will guide best practices for handling large collections of bacterial mutants.
Project description:Comparing gene expression of wild type and lsr2 mutants, to determine the effect of Lsr2 on Streptomyces development and metabolism