Project description:We previously developed a directed evolution model that passaged biofilm populations of in S. Typhimurium under antibiotic stress, which identified trade-offs between biofilm formation and antibiotic resistance, conferred by increased efflux activity (Trampari et al., 2021). We applied this same model to expose biofilm populations of S. Typhimurium to RND efflux inhibitor PAβN or non-antibiotic efflux substrate acriflavine. The aim was to identify mutations responsible for restoring biofilm formation in populations exposed to PAβN and to identify how cells in the biofilm can upregulate efflux in the presence of acriflavine. We hypothesised that comparing the mutations selected in both conditions would identify intersecting regulatory relationships between efflux activity and biofilm formation. Parallel linages of S. Typhimurium were grown on glass beads and in planktonic culture in the presence of a subinhibitory concentration of PAβN or acriflavine (or an untreated control) and passaged into new treated media every 48-72 hours. After one, five and ten passages (corresponding to 2, 17 and 35 days of continuous exposure), the populations were stored, DNA was extracted and sequenced to determine mutations selected in these conditions. We compared mutations from conditions treated with efflux substrates to untreated controls in planktonic and biofilm conditions. To explore phenotypic heterogeneity in these populations, we streaked biofilm populations from passages five and ten onto LB agar and picked three single colonies at random to sequence alongside the populations.
Project description:Pseudomonas aeruginosa is an opportunistic pathogen that can cause severe infections in immunocompromised individuals, such as patients with cystic fibrosis where it commonly forms biofilms. Ciprofloxacin is used extensively to treat P. aeruginosa infections, but its effectiveness can be significantly reduced due to biofilm formation. Although many individual genes associated with biofilm formation have been characterised, the genetic basis of P. aeruginosa biofilm fitness related to antibiotics challenge remain unexplored. In this study we employed a high-density TraDIS-Xpress library of P. aeruginosa PAO1 to assay the impact of gene disruptions or altered gene expression on biofilm formation at different concentrations of ciprofloxacin. Gene fitness was analysed by comparing the biofilm samples to planktonic samples harvested at 12h, 24h and 48h with and without ciprofloxacin. Gene determinants of survival for biofilms at different stages of maturity in the presence and absence of ciprofloxacin were identified.
Project description:To identify novel genes modulating Candida albicans biofilm formation, a screen of 2451 overexpression strains allowed us to identify 16 genes whose overexpression significantly reduced biofilm formation. Genome-wide expression and binding analyses were conducted upon overexpression of ZCF15 and ZCF26 and wild type planktonic and biofilm cells were performed. A ChIP assays was performed. Briefly, untagged strain (CEC4665) and two replicates each of ZCF15 (CEC5929 and CEC5930) and ZCF26 (CEC5931 and CEC5932) strain were grown in biofilm condition for 18 h and cells were cross-linked with 1% final concentration of formaldehyde for 25 min at 30°C.The DNA was immunoprecipitated with anti-protein A antibodies (Sigma Aldrich Cat. No. P3775). The immunoprecipitated (IP) DNA were used to determine the binding of Zcf15 and Zcf26 across the genome by ChIP-sequencing
Project description:Enterococcus faecalis is a common commensal organism and a prolific nosocomial pathogen that causes biofilm-associated infections. Numerous E. faecalis OG1RF genes required for biofilm formation have been identified, but few studies have compared genetic determinants of biofilm formation and biofilm morphology across multiple conditions. Here, we cultured transposon (Tn) libraries in CDC biofilm reactors in two different media and used Tn sequencing (TnSeq) to identify core and accessory biofilm determinants, including many genes that are poorly characterized or annotated as hypothetical. Multiple secondary assays (96-well plates, submerged Aclar, and MultiRep biofilm reactors) were used to validate phenotypes of new biofilm determinants.
Project description:This study is aimed to isolate marine actinomycetes from sediments from Andaman and the Gulf of Thailand. All 101 marine actinomycetes were screened for anti-biofilm activity. Streptomyces sp. GKU223 showed significantly inhibited biofilm formation of S. aureus. The evaluation of supernatants of anti-biofilm activity produced by Streptomyces sp. GKU223 has been performed. Since the interaction between marine actinomycetes and biofilm forming bacteria has never been investigated, proteomic analysis has been used to identify whole cell proteins involved in anti–biofilm activity. Understanding the interaction at molecular level will lead to sustainably use for anti-biofilm producing marine actinomycetes in pharmaceutical and medicinal applications in the future.
| PXD010815 | JPOST Repository
Project description:The fate and behavior mechanism of antibiotic resistance genes and microbial communities in flocs, aerobic granular and biofilm sludge under chloroxylenol pressure
| PRJNA816701 | ENA
Project description:The fate and behavior mechanism of antibiotic resistance genes and microbial communities in flocs, aerobic granular and biofilm sludge under chloroxylenol pressure
| PRJNA816694 | ENA
Project description:Nitrospira dominant pin-point flocs show granule-like settleability