Abstract:Urinary tract infection (UTI) is one the common infections caused by the recalcitrant nature of biofilms, developed after the pathogen has adhered to the inner lining of the urinary tract. Although significant research has been made in recent years to control these types of infection, but as of yet, no approach has sufficiently been able to reduce the prevalence of UTIs. The main objective of this study was to prevent UTIs through targeting the fimH gene, which is the major virulent factor responsible for biof… Show more
“…The reduction of the tetrazolium salts (XTT) from pale or light-colored to a brightly colored product known as formazans is the basis of the cell viability assay [30]. The XTT reduction data showed that 76.7% cells of InvF1 and 92% cells of InvF2 are viable in bolA knockdown cells which suggests that most of the bol-KD cells are viable and metabolically active [31]. A model has been proposed to show the functioning of bolA gene downregulation which affects the curli fibers, fimbriae and biofilm formation (Fig.…”
Background: Biofilm formation is a complex phenomenon of bacterial cells, involved in several human infections. Its formation is regulated and controlled by several protein factors. The BolA-like proteins (bolA gene) are conserved in both prokaryotes and eukaryotes. The BolA protein is a transcription factor involved in bacterial cell motility and biofilm formation. This study was initiated to elucidate the role of the bolA gene in the curli biogenesis and amyloid production as well as to observe changes in the expression of fimH, a fimbriae gene. Methods: Knockdown mutants of Escherichia coli MG1655 bolA gene (bolA-KD) were generated using CRISPR interference. The results obtained, were validated through gene expression using RT-PCR, microscopic analysis and different biofilm and amyloid assays. Results: The bolA knockdown mutants showed a decrement in curli amyloid fibers, in fimbriae production and biofilm formation. We have also observed a reduction in EPS formation, eDNA production and extracellular protein content. Gene expression data showed that bolA downregulation caused the suppression of csgA and csgD of curli that led to the reduction in curli fiber and the amyloid formation and also the suppression of fimH, leading to the loss of fimbriae. Conclusions: Curli fibers and fimbriae are found to be involved in biofilm formation leading to the pathogenicity of the bacterial cell. BolA is a conserved protein and is found to play a significant role in curli and fimbriae formation in E. coli. This study further proved that CRISPRi mediated suppression of the bolA gene leads to inhibition of biofilm formation through curli and fimbriae inhibition. Hence, it may be proposed as a possible target for intervention of biofilm mediated infections.
“…The reduction of the tetrazolium salts (XTT) from pale or light-colored to a brightly colored product known as formazans is the basis of the cell viability assay [30]. The XTT reduction data showed that 76.7% cells of InvF1 and 92% cells of InvF2 are viable in bolA knockdown cells which suggests that most of the bol-KD cells are viable and metabolically active [31]. A model has been proposed to show the functioning of bolA gene downregulation which affects the curli fibers, fimbriae and biofilm formation (Fig.…”
Background: Biofilm formation is a complex phenomenon of bacterial cells, involved in several human infections. Its formation is regulated and controlled by several protein factors. The BolA-like proteins (bolA gene) are conserved in both prokaryotes and eukaryotes. The BolA protein is a transcription factor involved in bacterial cell motility and biofilm formation. This study was initiated to elucidate the role of the bolA gene in the curli biogenesis and amyloid production as well as to observe changes in the expression of fimH, a fimbriae gene. Methods: Knockdown mutants of Escherichia coli MG1655 bolA gene (bolA-KD) were generated using CRISPR interference. The results obtained, were validated through gene expression using RT-PCR, microscopic analysis and different biofilm and amyloid assays. Results: The bolA knockdown mutants showed a decrement in curli amyloid fibers, in fimbriae production and biofilm formation. We have also observed a reduction in EPS formation, eDNA production and extracellular protein content. Gene expression data showed that bolA downregulation caused the suppression of csgA and csgD of curli that led to the reduction in curli fiber and the amyloid formation and also the suppression of fimH, leading to the loss of fimbriae. Conclusions: Curli fibers and fimbriae are found to be involved in biofilm formation leading to the pathogenicity of the bacterial cell. BolA is a conserved protein and is found to play a significant role in curli and fimbriae formation in E. coli. This study further proved that CRISPRi mediated suppression of the bolA gene leads to inhibition of biofilm formation through curli and fimbriae inhibition. Hence, it may be proposed as a possible target for intervention of biofilm mediated infections.
“…Therefore to overcome the drug resistance of bacterial biofilm communities; alternative strategies (Fig. 2) and novel antibiofilm agents have been studied earlier [9, 48–50, 54, 63, 64, 69, 74, 86–88, 92, 128, 131, 148, 153, 154]. Fig.…”
Section: Introductionmentioning
confidence: 99%
“…Signalling molecule nitric oxide (NO) disperse the biofilms in P. aeruginosa and enhances the activity of antimicrobial compounds via stimulation of c-di-GMP-degrading phosphodiesterases, which induce a switch to planktonic growth [12]. Most recently our group used the CRISPRi technology to knockdown the luxS gene of QS signalling and fimbriae associated gene (fimH) for controlling the biofilm mediated infections [153, 154].…”
Biofilm is a complex structure of microbiome having different bacterial colonies or single type of cells in a group; adhere to the surface. These cells are embedded in extracellular polymeric substances, a matrix which is generally composed of eDNA, proteins and polysaccharides, showed high resistance to antibiotics. It is one of the major causes of infection persistence especially in nosocomial settings through indwelling devices. Quorum sensing plays an important role in regulating the biofilm formation. There are many approaches being used to control infections by suppressing its formation but CRISPR-CAS (gene editing technique) and photo dynamic therapy (PDT) are proposed to be used as therapeutic approaches to subside bacterial biofim infections, especially caused by deadly drug resistant bad bugs.
“…For instance, type 3 fimbriae were found to strongly promote biofilm formation for Klebsiella pneumoniae [17][18][19][20]. Bak et al [21], Zuberi et al [22], and Lasaro et al [23] showed that biofilm formation in Escherichia coli is inhibited when type 1 fimbriae are suppressed. Rodrigues and Elimelech [24] and Wang et al [25] examined role of type 1 fimbriae for biofilm formation of E. coli, with fimbriaed, non-fimbriaed and wild bacteria.…”
Gram-negative bacteria, as well as some Gram-positive bacteria, possess hair-like appendages known as fimbriae, which play an important role in adhesion of the bacteria to surfaces or to other bacteria. Unlike the sex pili or flagellum, the fimbriae are quite numerous, with of order 1000 fimbriae appendages per bacterial cell. In this paper, a recently developed hybrid model for bacterial biofilms is used to examine the role of fimbriae tension force on the mechanics of bacterial biofilms. Each bacterial cell is represented in this model by a spherocylindrical particle, which interact with each other through collision, adhesion, lubrication force, and fimbrial force. The bacterial cells absorb water and nutrients and produce extracellular polymeric substance (EPS). The flow of water and EPS, and nutrient diffusion within these substances, is computed using a continuum model that accounts for important effects such as osmotic pressure gradient, drag force on the bacterial cells, and viscous shear. The fimbrial force is modeled using an outer spherocylinder capsule around each cell, which can transmit tensile forces to neighboring cells with which the fimbriae capsule collides. We find that the biofilm structure during the growth process is dominated by a balance between outward drag force on the cells due to the EPS flow away from the bacterial colony and the inward tensile fimbrial force acting on chains of cells connected by adhesive fimbriae appendages. The fimbrial force also introduces a large rotational motion of the cells and disrupts cell alignment caused by viscous torque imposed by the EPS flow. The current paper characterizes the competing effects of EPS drag and fimbrial force using a series of computations with different values of the ratio of EPS to bacterial cell production rate and different numbers of fimbriae per cell.
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