Project description:Interactions between human keratinocytes and secreted factors from Staphylococcus aureus biofilm and planktonic cultures were investigated using microarray analysis. Relative to planktonic secreted factors, biofilm secreted factors up regulated cytokine and chemokine genes in keratinocytes. Genes associated with DNA damage and oxidative stress were also induced in keratinocytes treated with secreted factors from S. aureus biofilm. Here we show that secreted factors from S. aureus planktonic (PCM) and biofilm (BCM) cultures differentially impact several aspects of wound healing processes.
Project description:Interactions between human keratinocytes and secreted factors from Staphylococcus aureus biofilm and planktonic cultures were investigated using microarray analysis. Relative to planktonic secreted factors, biofilm secreted factors up regulated cytokine and chemokine genes in keratinocytes. Genes associated with DNA damage and oxidative stress were also induced in keratinocytes treated with secreted factors from S. aureus biofilm. Here we show that secreted factors from S. aureus planktonic (PCM) and biofilm (BCM) cultures differentially impact several aspects of wound healing processes. Secreted factors from S. aureus biofilm and planktonic cultures with equivalent population sizes were placed in contact with human foreskin keratinocytes for 4 hours. Keratinocytes were grown to ~90% confluency between passages 4-10.
Project description:Interactions between human keratinocytes and secreted factors from Staphylococcus aureus biofilm were investigated using microarray analysis. Relative to control cells, biofilm-secreted factors upregulated cytokine and chemokine genes in keratinocytes. Genes associated with DNA damage and oxidative stress were also induced in keratinocytes treated with secreted factors from S. aureus. Here we show that secreted factors from S. aureus biofilm cultures differentially impact several aspects of wound healing processes.
Project description:Interactions between human keratinocytes and secreted factors from Staphylococcus aureus biofilm were investigated using microarray analysis. Relative to control cells, biofilm-secreted factors upregulated cytokine and chemokine genes in keratinocytes. Genes associated with DNA damage and oxidative stress were also induced in keratinocytes treated with secreted factors from S. aureus. Here we show that secreted factors from S. aureus biofilm cultures differentially impact several aspects of wound healing processes. Human keratinocytes were grown in co-culture with mature S. aureus biofilms for 24 hours. Keratinocytes exposed to S. aureus biofilm were analyzed in quadruplicate. Control cells were also analyzed in quadruplicate. Dye-swaps were performed.
Project description:Staphylococcus aureus produces the cyclic dipeptides tyrvalin and phevalin (aureusimine A and B, respectively). A previous study reported that S. aureus mutants not capable of producing these compounds were less virulent in vivo through the deranged regulation of virulence factor genes. These findings, however, have been questioned as an unknown mutation in an operon that regulates virulence was discovered in the mutant strain. Here, we report that S. aureus biofilms produce greater amounts of phevalin than their planktonic counterparts. When administered to human keratinocytes, phevalin had no substantial effect on gene expression. Phevalin had no obvious impact on the extracellular metabolome of S. aureus. However, conditioned medium from S. aureus spiked with phevalin resulted in significant differences in keratinocyte gene expression compared to conditioned medium alone. A role for phevalin in manipulating host responses is apparent. Additionally, phevalin is a potential biomarker and/or therapeutic target for chronic, biofilm-based infections. Secreted factors from S. aureus biofilm and planktonic cultures with equivalent population sizes were placed in contact with human HaCaT keratinocytes for 4 hours. Keratinocytes were grown to ~90% confluency.
Project description:In planktonic and biofilm mimicking environments, the staphyloccocal transcriptome in t111+t13595 co-cultures showed significant upregulation of genes related to virulence factors contrary to those co-cultures with B. thuringiesis and K. oxytoca. In the biofilm polymicrobial environment, S. aureus transcriptome shows extensive downregulation of gene expression. The animal model co-infection with S. aureus and K. oxytoca proved to be less virulent than when infected only with S. aureus alone, or K. oxytoca alone where higher infection and mortality rates were observed.
Project description:Purpose: Study transcriptome differences between biofilm, planktonic and stationary cultures. Methods: Total mRNA from in vitro cultures was extracted and sequenced using Ion Torrent PGM sequencer. Results: Characteristic transcriptomic profile was observed for biofilm, planktonic and stationary cultures. Biofilm and planktonic were similar biological states. Conclusions: Results suggest that H. parasuis F9 has more active metabolism during biofilm or planktonic growth when compared to stationary culture. Some identified membrane-related genes could play an important role in biofilm life.
Project description:In this work we have demonstrated increased mutability of Staphylococcus aureus and S. epidermidis in biofilms and have explored the mechanisms underlying the enhanced mutability. A novel static biofilm model, utilising cellulose filter disks, was developed to support the formation of mature biofilms with sufficiently high cell densities to permit determination of mutation frequencies. The mutability of biofilm cultures increased up to 60 fold and 4 fold for S. aureus and S. epidermidis, respectively, compared with planktonic cultures. Incorporation of antioxidants into S. aureus biofilms reduced mutation frequencies, indicating that increased oxidative stress underlies increased mutability in the biofilm. Transcriptional profiling revealed upregulation of the superoxide dismutase gene, sodA, in early biofilm cultures, also suggesting enhanced oxidative stress in these cultures. However, loss of the genes encoding superoxide dismutases or peroxidases did not specifically exacerabate biofilm mutability. In S. aureus SH1000, hydrogen peroxide was found to contribute to biofilm mutability. Three growth conditions (18 hr planktonic growth, 48 hr biofilm growth and 144 biofilm growth) of which there are three biological replicates of each
Project description:In this work we have demonstrated increased mutability of Staphylococcus aureus and S. epidermidis in biofilms and have explored the mechanisms underlying the enhanced mutability. A novel static biofilm model, utilising cellulose filter disks, was developed to support the formation of mature biofilms with sufficiently high cell densities to permit determination of mutation frequencies. The mutability of biofilm cultures increased up to 60 fold and 4 fold for S. aureus and S. epidermidis, respectively, compared with planktonic cultures. Incorporation of antioxidants into S. aureus biofilms reduced mutation frequencies, indicating that increased oxidative stress underlies increased mutability in the biofilm. Transcriptional profiling revealed upregulation of the superoxide dismutase gene, sodA, in early biofilm cultures, also suggesting enhanced oxidative stress in these cultures. However, loss of the genes encoding superoxide dismutases or peroxidases did not specifically exacerabate biofilm mutability. In S. aureus SH1000, hydrogen peroxide was found to contribute to biofilm mutability.