The authors have shown that twitching motility, a pilus-mediated form of bacterial surface moveme... more The authors have shown that twitching motility, a pilus-mediated form of bacterial surface movement, is required for Pseudomonas aeruginosa virulence in a murine model of keratitis.
Pseudomonas aeruginosa can invade corneal epithelial cells and translocates multilayered corneal ... more Pseudomonas aeruginosa can invade corneal epithelial cells and translocates multilayered corneal epithelia in vitro, but it does not penetrate the intact corneal epithelium in vivo. In healthy corneas, the epithelium is separated from the underlying stroma by a basement membrane containing extracellular matrix proteins and pores smaller than bacteria. Here we used in vivo and in vitro models to investigate the potential of the basement membrane to defend against P. aeruginosa. Transmission electron microscopy of infected mouse corneas in vivo showed penetration of the stroma by P. aeruginosa only where the basement membrane was visibly disrupted by scratch injury, suggesting that the intact basement membrane prevented penetration. This hypothesis was explored using an in vitro Matrigel Transwell model to mimic the corneal basement membrane.
In Vitro Cellular & Developmental Biology - Animal, 2002
To catalog factors that may contribute to the completion of myogenesis, we have been looking for ... more To catalog factors that may contribute to the completion of myogenesis, we have been looking for molecular differences between BC3HI and C2C12 cells. Cells of the BC3H1 tumor line, though myogenic, are nonfusing, and withdraw from the cell cycle only reversibly, whereas cells of the C2C12 nine fuse, differentiate terminally, and express several muscle-specific gene products that BC3H1 cells do not. Relative to C2C12 cells, BC3H1 ceils underaccumulated cyclin-dependent kinase inhibitor p21 and underaccumulated transcripts for p21, GADD45, CDO, decorin, osteopontin, H19, fibronectin, and thrombospondin-1 (tsp-1). Levels of accumulation of H19, tsp-1, and larger isoforms of fibronectin messenger ribonucleic acid (mRNA) were found to increase in response to expression of myogenic regulatory factors as shown by their accumulation in differentiated myogenically converted lOT1/2 cells but not in 10T1/2 fibroblasts. BC3Hls accumulated a temperature-insensitive, geldanamycin-sensitive, misfolded form of p53 incapable of transactivating a p53 responsive reporter, consistent with underexpression of p21, GADD45, and tsp-1. BC3H1 and C2C12 cells were similar with respect to upregulation of p27 protein, downregulation of mitogen-activated protein kinase phosphatase-1 (MKP-1) protein, upregulation of retinoblastoma (Rb) mRNA, and nuclear localization of hypophosphorylated Rb. Cells of both lines expressed the muscle-specific lb isoform of MEF2D. Although nonfusing in the short term, after more than 18 d in differentiation medium, some cultures of BC3H1 cells formed viable muhinucleated cells in which the nuclei did not reinitiate synthesis of DNA in response to serum. Our findings suggest participation of tsp-1 and specific isoforms of fibronectin in myogenesis and suggest additional avenues of research in myogenesis and oncogenesis.
The authors have shown that twitching motility, a pilus-mediated form of bacterial surface moveme... more The authors have shown that twitching motility, a pilus-mediated form of bacterial surface movement, is required for Pseudomonas aeruginosa virulence in a murine model of keratitis.
Pseudomonas aeruginosa can invade corneal epithelial cells and translocates multilayered corneal ... more Pseudomonas aeruginosa can invade corneal epithelial cells and translocates multilayered corneal epithelia in vitro, but it does not penetrate the intact corneal epithelium in vivo. In healthy corneas, the epithelium is separated from the underlying stroma by a basement membrane containing extracellular matrix proteins and pores smaller than bacteria. Here we used in vivo and in vitro models to investigate the potential of the basement membrane to defend against P. aeruginosa. Transmission electron microscopy of infected mouse corneas in vivo showed penetration of the stroma by P. aeruginosa only where the basement membrane was visibly disrupted by scratch injury, suggesting that the intact basement membrane prevented penetration. This hypothesis was explored using an in vitro Matrigel Transwell model to mimic the corneal basement membrane.
In Vitro Cellular & Developmental Biology - Animal, 2002
To catalog factors that may contribute to the completion of myogenesis, we have been looking for ... more To catalog factors that may contribute to the completion of myogenesis, we have been looking for molecular differences between BC3HI and C2C12 cells. Cells of the BC3H1 tumor line, though myogenic, are nonfusing, and withdraw from the cell cycle only reversibly, whereas cells of the C2C12 nine fuse, differentiate terminally, and express several muscle-specific gene products that BC3H1 cells do not. Relative to C2C12 cells, BC3H1 ceils underaccumulated cyclin-dependent kinase inhibitor p21 and underaccumulated transcripts for p21, GADD45, CDO, decorin, osteopontin, H19, fibronectin, and thrombospondin-1 (tsp-1). Levels of accumulation of H19, tsp-1, and larger isoforms of fibronectin messenger ribonucleic acid (mRNA) were found to increase in response to expression of myogenic regulatory factors as shown by their accumulation in differentiated myogenically converted lOT1/2 cells but not in 10T1/2 fibroblasts. BC3Hls accumulated a temperature-insensitive, geldanamycin-sensitive, misfolded form of p53 incapable of transactivating a p53 responsive reporter, consistent with underexpression of p21, GADD45, and tsp-1. BC3H1 and C2C12 cells were similar with respect to upregulation of p27 protein, downregulation of mitogen-activated protein kinase phosphatase-1 (MKP-1) protein, upregulation of retinoblastoma (Rb) mRNA, and nuclear localization of hypophosphorylated Rb. Cells of both lines expressed the muscle-specific lb isoform of MEF2D. Although nonfusing in the short term, after more than 18 d in differentiation medium, some cultures of BC3H1 cells formed viable muhinucleated cells in which the nuclei did not reinitiate synthesis of DNA in response to serum. Our findings suggest participation of tsp-1 and specific isoforms of fibronectin in myogenesis and suggest additional avenues of research in myogenesis and oncogenesis.
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