AIM: To investigate the resistance to bacterial adhesion of materials used in oculoplastic surgery, particularly materials used in the manufacture of orbital implants.METHODS: Seven organisms of conjunctival flora(two...AIM: To investigate the resistance to bacterial adhesion of materials used in oculoplastic surgery, particularly materials used in the manufacture of orbital implants.METHODS: Seven organisms of conjunctival flora(two strains of Staphylococcus epidermidis and one strain each of Staphylococcus aureus, Staphylococcus hominis, Corynebacterium amycolatum, Acinetobacter calcoaceticus, and Serratia marcescens) were selected. A lactic acid bacterium(Lactobacillus rhamnosus) was also included as positive control because of its well-known adhesion ability. Eight materials used to make oculoplastic prostheses were selected(glass, steel, polytetrafluoroethylene, polymethylmethacrylate, silicone from orbital implants, commercial silicone, porous polyethylene, and semismooth polyethylene). Materials surfaces and biofilms developed by strains were observed by scanning electron microscopy. Kinetics of growth and adhesion of bacterial strains were determined by spectrophotometry. Each strain was incubated in contact with plates of the different materials. After growth, attached bacteria were re-suspended and colony-forming units(CFUs) were counted. The number of CFUs per square millimetre of material was statistically analyzed.RESULTS: A mature biofilm was observed in studied strains except Staphylococcus hominis, which simply produced a microcolony. Materials showed a smooth surface on the microbial scale, although steel exhibited 1.0-μm-diameter grooves. Most organisms showed significant differences in adhesion according to the material. There were also significant differences in thetotal number of CFUs per square millimetre from each material(P=0.044). CFU counts were significantly higher in porous polyethylene than in silicone from orbital implants(P=0.038).CONCLUSION: Silicone orbital implants can resist microbial colonization better than porous polyethylene implants.展开更多
Biological and synthetic surfactants were compared in terms of their ability to reduce interfacial tension, change the thermodynamic characteristics of a pre-conditioned surface, and to modify the rheological properti...Biological and synthetic surfactants were compared in terms of their ability to reduce interfacial tension, change the thermodynamic characteristics of a pre-conditioned surface, and to modify the rheological properties of their respective formulations at two different temperatures. Both classes of suffactants were able to reduce the inteffacial tension of their formulations to a similar level. However, the biosurfactants were more effective than the synthetics surfactants. Biosurfactants also altered the surface properties of stainless steel, rendering it hydrophilic. Microbial adhesion to stainless steel conditioned with biosurfactants was found to be thermodynamically unfavorable for all microbial strains tested. A linear relationship between shear stress and shear rate was obtained across a range of experimental conditions for all surfactant mixtures, indicating that all formulations behaved as Newtonian fluids.展开更多
The study links targeted cell surface characterization to the quantified capacity of cellulose degrading Pseudomonas fluorescens cells to colonize a (similarly characterized) cellulosic carrier. The experiments were c...The study links targeted cell surface characterization to the quantified capacity of cellulose degrading Pseudomonas fluorescens cells to colonize a (similarly characterized) cellulosic carrier. The experiments were conducted to clarify the effect of cultivation conditions on the achieved state of this carrier colonization. The suggested approach seems to be sufficient to verify the right choice of cultivation medium as a major factor determining the binding complementarity between microbial cells and solid cellulose.展开更多
Bone sialoprotein-binding protein （Bbp）, a MSCRAMMs （Microbial Surface Components Recognizing Adhesive Matrix Molecules） family protein expressed on the surface of Staphylococcus aureus （S. aureus）, mediates adh...Bone sialoprotein-binding protein （Bbp）, a MSCRAMMs （Microbial Surface Components Recognizing Adhesive Matrix Molecules） family protein expressed on the surface of Staphylococcus aureus （S. aureus）, mediates adherence to fibrinogen a （Fg a）, a component in the extracellular matrix of the host cell and is important for infection and pathogenesis. In this study, we solved the crystal structures of apo-Bbp273-598 and Bbp273-598-Fg a561-575 complex at a resolution of 2.03 A and 1.45 A, respectively. Apo-Bbp273-598 contained the ligand binding region N2 and N3 domains, both of which followed a DE variant IgG fold characterized by an additional DI strand in N2 domain and D1＇ and D2＇ strands in N3 domain. The peptide mapped to the Fg o561-575 bond to Bbp273-sgs on the open groove between the N2 and N3 domains. Strikingly, the disordered C-terminus in the apo-form reorganized into a highly-ordered loop and a β-strand G＂ covering the ligand upon ligand binding. BbpAla298-Gly301 in the N2 domain of the Bbp273-598-Fg a561-575 complex, which is a loop in the apo-form, formed a short a-helix to interact tightly with the peptide. In addition, Bbpser547-Glns61 in the N3 domain moved toward the binding groove to make contact directly with the peptide, while BbpAsp338-Gly355 and BbpThr365-Tyr387 in N2 domain shifted their configurations to stabilize the reorganized C-terminus mainly through strong hydrogen bonds. Altogether, our results revealed the molecular basis for Bbp-ligand interaction and advanced our understanding of S. aureus infection process.展开更多
基金Supported by the Dirección General de Investigación(SAF 2015-64306-R)the Junta de Castilla y León,Spain(LE283U14)
文摘AIM: To investigate the resistance to bacterial adhesion of materials used in oculoplastic surgery, particularly materials used in the manufacture of orbital implants.METHODS: Seven organisms of conjunctival flora(two strains of Staphylococcus epidermidis and one strain each of Staphylococcus aureus, Staphylococcus hominis, Corynebacterium amycolatum, Acinetobacter calcoaceticus, and Serratia marcescens) were selected. A lactic acid bacterium(Lactobacillus rhamnosus) was also included as positive control because of its well-known adhesion ability. Eight materials used to make oculoplastic prostheses were selected(glass, steel, polytetrafluoroethylene, polymethylmethacrylate, silicone from orbital implants, commercial silicone, porous polyethylene, and semismooth polyethylene). Materials surfaces and biofilms developed by strains were observed by scanning electron microscopy. Kinetics of growth and adhesion of bacterial strains were determined by spectrophotometry. Each strain was incubated in contact with plates of the different materials. After growth, attached bacteria were re-suspended and colony-forming units(CFUs) were counted. The number of CFUs per square millimetre of material was statistically analyzed.RESULTS: A mature biofilm was observed in studied strains except Staphylococcus hominis, which simply produced a microcolony. Materials showed a smooth surface on the microbial scale, although steel exhibited 1.0-μm-diameter grooves. Most organisms showed significant differences in adhesion according to the material. There were also significant differences in thetotal number of CFUs per square millimetre from each material(P=0.044). CFU counts were significantly higher in porous polyethylene than in silicone from orbital implants(P=0.038).CONCLUSION: Silicone orbital implants can resist microbial colonization better than porous polyethylene implants.
文摘Biological and synthetic surfactants were compared in terms of their ability to reduce interfacial tension, change the thermodynamic characteristics of a pre-conditioned surface, and to modify the rheological properties of their respective formulations at two different temperatures. Both classes of suffactants were able to reduce the inteffacial tension of their formulations to a similar level. However, the biosurfactants were more effective than the synthetics surfactants. Biosurfactants also altered the surface properties of stainless steel, rendering it hydrophilic. Microbial adhesion to stainless steel conditioned with biosurfactants was found to be thermodynamically unfavorable for all microbial strains tested. A linear relationship between shear stress and shear rate was obtained across a range of experimental conditions for all surfactant mixtures, indicating that all formulations behaved as Newtonian fluids.
基金the financial support of MEYS,Czech Republic,through the projects:Eureka E!3654-Euroenviron Biopolsthe Project OP VaVpI Centre for Nanomaterials,Advanced Technologies and Innovation CZ.1.05/2.1.00/01.0005the Grant Agency of the Czech Republic(project GACR P503/12/1424).
文摘The study links targeted cell surface characterization to the quantified capacity of cellulose degrading Pseudomonas fluorescens cells to colonize a (similarly characterized) cellulosic carrier. The experiments were conducted to clarify the effect of cultivation conditions on the achieved state of this carrier colonization. The suggested approach seems to be sufficient to verify the right choice of cultivation medium as a major factor determining the binding complementarity between microbial cells and solid cellulose.
文摘Bone sialoprotein-binding protein （Bbp）, a MSCRAMMs （Microbial Surface Components Recognizing Adhesive Matrix Molecules） family protein expressed on the surface of Staphylococcus aureus （S. aureus）, mediates adherence to fibrinogen a （Fg a）, a component in the extracellular matrix of the host cell and is important for infection and pathogenesis. In this study, we solved the crystal structures of apo-Bbp273-598 and Bbp273-598-Fg a561-575 complex at a resolution of 2.03 A and 1.45 A, respectively. Apo-Bbp273-598 contained the ligand binding region N2 and N3 domains, both of which followed a DE variant IgG fold characterized by an additional DI strand in N2 domain and D1＇ and D2＇ strands in N3 domain. The peptide mapped to the Fg o561-575 bond to Bbp273-sgs on the open groove between the N2 and N3 domains. Strikingly, the disordered C-terminus in the apo-form reorganized into a highly-ordered loop and a β-strand G＂ covering the ligand upon ligand binding. BbpAla298-Gly301 in the N2 domain of the Bbp273-598-Fg a561-575 complex, which is a loop in the apo-form, formed a short a-helix to interact tightly with the peptide. In addition, Bbpser547-Glns61 in the N3 domain moved toward the binding groove to make contact directly with the peptide, while BbpAsp338-Gly355 and BbpThr365-Tyr387 in N2 domain shifted their configurations to stabilize the reorganized C-terminus mainly through strong hydrogen bonds. Altogether, our results revealed the molecular basis for Bbp-ligand interaction and advanced our understanding of S. aureus infection process.
