Project description:Insights into the bacterial biofilm community of the Mediterranean seagrass Posidonia oceanica and description of novel Planctomycetes - Genome sequencing and assembly
Project description:Transcription profile of Escherichia coli cells in mono-species pure biofilms was compared to that of E. coli cells in E. coli-Stenotrophomonas maltophilia dual-species biofilms. E. coli cells were separated from dual-species biofilms 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 biofilms were processed with the same separation protocol before RNA extraction.
Project description:Transcription profile of Escherichia coli cells in mono-species pure biofilms was compared to that of E. coli cells in E. coli-Stenotrophomonas maltophilia dual-species biofilms. E. coli cells were separated from dual-species biofilms 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 biofilms were processed with the same separation protocol before RNA extraction. Two condition experiments: E. coli mono-species biofilm vs E. coli in mixed-species biofilm. Two biological replicates with independently grown and harvested biofilms. Each biological replicate has two or three technical replicates of hybridization on microarray slides. Each slide has three built-in replicates for each probe.
Project description:To explain enhanced biofilm formation and increased dissemination of S. epidermidis in mixed-species biofilms, microarrays were used to explore differential gene expression of S. epidermidis in mixed-species biofilms. One sample from single species biofilm (S1) and mixed-species biofilm (SC2) were excluded from analyses for outliers. We observed upregulation (2.7%) and down regulation (6%) of S. epidermidis genes in mixed-species biofilms. Autolysis repressors lrgA and lrgB were down regulated 36-fold and 27-fold respectively and was associated with increased eDNA possibly due to enhanced autolysis in mixed-species biofilms. These data suggest that bacterial autolysis and release of eDNA in the biofilm matrix may be responsible for enhancement and dissemination of mixed-species biofilms of S. epidermidis and C. albicans. Staphylococcal gene expression in mixed-species biofilms with Candida and in single species biofilms of S. epidermidis were analyzed. The experiment was repeated thrice on 3 different days (3 biological replicates each for single species biofilms of S. epidermidis and mixed-species biofilms). Only 2 biological replicates were analyzed and one biological replicate was not analyzed (S1 and SC1 - raw data files are provided on the Series record). Single species biofilms of S. epidermidis (strain 1457) and C. albicans (strain 32354) and mixed-species biofilms were formed on 6-well tissue culture plates. Five ml of organism suspensions (O.D. 0.3, S. epidermidis 107 CFU/ml or C. albicans 105 CFU/ml) or 2.5 ml each for mixed-species biofilms for 24 hr. RNA was harvested from single species and mixed-species biofilms.
Project description:We examined the differential gene expression of Staphylococcus epidermidis and Staphylococcus epidermidis in dual species biofilms. Therefore, we performed RNA-Seq on single and dual species biofilms and we compared the gene expression levels in dual species biofilms to those in single species biofilms.
Project description:To explain enhanced biofilm formation and increased dissemination of S. epidermidis in mixed-species biofilms, microarrays were used to explore differential gene expression of S. epidermidis in mixed-species biofilms. One sample from single species biofilm (S1) and mixed-species biofilm (SC2) were excluded from analyses for outliers. We observed upregulation (2.7%) and down regulation (6%) of S. epidermidis genes in mixed-species biofilms. Autolysis repressors lrgA and lrgB were down regulated 36-fold and 27-fold respectively and was associated with increased eDNA possibly due to enhanced autolysis in mixed-species biofilms. These data suggest that bacterial autolysis and release of eDNA in the biofilm matrix may be responsible for enhancement and dissemination of mixed-species biofilms of S. epidermidis and C. albicans.
Project description:Polymicrobial biofilms are of large medical importance, but little is known about their physiology and the underlying interspecies interactions. Here we studied two human pathogens, the opportunistic fungus Candida albicans and the caries promoting bacterium Streptococcus mutans. Both species formed biofilms in monoculture, with C. albicans growing mainly in the virulence-associated hyphae form, and S. mutans forming a thick layer of extracellular polymeric substances (EPS). Biofilm growth was enhanced in dual-species biofilms, which reached twice the biomass of monospecies biofilms and higher cell numbers of both S. mutans and C. albicans. EPS production by S. mutans was strongly suppressed in dual-species biofilms. Virulence traits of S. mutans, e.g. genetic competence, biofilm formation and bacteriocin synthesis are controlled by quorum sensing through activation of the alternative sigma factor SigX. SigX is induced by the pheromones CSP (competence stimulating factor) or XIP (sigX inducing peptide). Strong induction of sigX was observed in dual species biofilms indicated by fluorescence of a reporter strain for the sigX promoter, S. mutans PcomX-gfp, as well as by qRT-PCR of comX. The peak of sigX expression occurred after 10 h of biofilm growth. Conditioned media from mixed biofilms but not from C. albicans or S. mutans cultivated alone activated sigX in the reporter strain. Deletion mutants for the comC and comS genes encoding the precursors of CSP and XIP, respectively, were constructed. Conditioned media from mixed biofilms with S. mutans DcomS were unable to induce sigX in the reporter strain, while deletion of comC had no effect. These data show that synthesis of XIP was induced in S. mutans by coculture with C. albicans. Transcriptome analysis of S. mutans in single and mixed biofilms confirmed strong induction of comS, sigX, and the downstream late competence genes in dual-species biofilms. Among the late competence genes, fratricins were discovered for the first time. The comCDE operon and bacteriocin related genes were also induced, but much weaker. Genes related to oxidative stress, chaperones and glycosyltransferase genes required for EPS synthesis from sucrose were down-regulated, while glycogen synthesis genes were up-regulated, indicating that S. mutans was protected from oxidative stress and provided with excess sugar for storage polymer synthesis in mixed biofilms. The data show that in dual-species biofilms, C. albicans improves growth of S. mutans, suppresses its EPS formation and induces the complete quorum sensing signalling system, thus fundamentally changing the virulence properties of the caries pathogen, including its potential interactions with other members of the polymicrobial dental plaque community. Dual-species biofilms of S. mutans and C. albicans and single-species biofilms of S. mutans were cultivated in 24-well microtitre plates in YNBB medium. Transcriptional profiles of S. mutans in single- and dual-species biofilms were analysed at early (6 h) and late (10 h) logarithmic phase of the biofilm growth, as well as after 24 h when biofilms entered stationary phase. Transcriptional profiles of S. mutans grown in the dual-species biofilms were compared to profiles obtained for single-species biofilm from the same time point. Three biological and one to two technical replicas were used in the microarray study. RNA samples were labeled with Cy3 or Cy5 using the ULS fluorescent labeling kit (Kreatech, Germany). Seven hundred nanograms of Cy3 or Cy5 labeled RNA after fragmentation were hybridized to the microarray at 65M-BM-0C for 17 h using the Agilent hybridization chamber according to the manufacturer's instructions. The arrays were scanned using the Agilent DNA microarray scanner and the raw data were extracted using Agilent Feature Extraction software (v. 10.7).