Nanoscale Characterization and Determination of Adhesion Forces of
            <i>Pseudomonas aeruginosa</i>
            Pili by Using Atomic Force Microscopy

Touhami, Ahmed; Jericho, M. H.; Boyd, Jessica M.; Beveridge, Terry J.

doi:10.1128/jb.188.2.370-377.2006

Cited by 151 publications

(174 citation statements)

References 35 publications

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“…These results suggest that the transition need not invoke the entire Tfp but can consist of multiple transitions of regions within the Tfp. The AFM data presented here are similar to previous experiments performed on Pseudomonas aeruginosa Tfp (30). In those experiments, the Tfp tested were not purified and were still attached to the bacterium body leading to the hypothesis that the AFM data could be caused by a component of the bacterial wall.…”

Section: Atomic Force Microscopy (Afm) Characterization Of the Force-supporting

confidence: 86%

Force-dependent polymorphism in type IV pili reveals hidden epitopes

Biais

Higashi

Brujić

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

120

126

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Through evolution, nature has produced exquisite nanometric structures, with features unrealized in the most advanced manmade devices. Type IV pili (Tfp) represent such a structure: 6-nmwide retractable filamentous appendages found in many bacteria, including human pathogens. Whereas the structure of Neisseria gonorrhoeae Tfp has been defined by conventional structural techniques, it remains difficult to explain the wide spectrum of functions associated with Tfp. Here we uncover a previously undescribed force-induced quaternary structure of the N. gonorrhoeae Tfp. By using a combination of optical and magnetic tweezers, atomic force microscopy, and molecular combing to apply forces on purified Tfp, we demonstrate that Tfp subjected to approximately 100 pN of force will transition into a new conformation. The new structure is roughly 3 times longer and 40% narrower than the original structure. Upon release of the force, the Tfp fiber regains its original form, indicating a reversible transition. Equally important, we show that the force-induced conformation exposes hidden epitopes previously buried in the Tfp fiber. We postulate that this transition provides a means for N. gonorrhoeae to maintain attachment to its host while withstanding intermittent forces encountered in the environment. Our findings demonstrate the need to reassess our understanding of Tfp dynamics and functions. They could also explain the structural diversity of other helical polymers while presenting a unique mechanism for polymer elongation and exemplifying the extreme structural plasticity of biological polymers.force polymorphism | alternate immunogenic properties

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Section: Atomic Force Microscopy (Afm) Characterization Of the Force-supporting

confidence: 86%

Force-dependent polymorphism in type IV pili reveals hidden epitopes

Biais

Higashi

Brujić

et al. 2010

Proc. Natl. Acad. Sci. U.S.A.

120

126

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“…FITC-ConA is known to selectively bind to the mannose and glucose residues of biofi lm polysaccharides [13]. PI is a fl uorescent nucleic acid stain that enters dead/nonviable by binding to double-stranded nucleic acids through intercalation between base pairs with no preference to purine or pyrimidine base pairs [14]. Figure 4 shows intense green fl uorescence (arrow B) resulting from ConA binding to polysaccharides of C. albicans while PI penetrates only cells with damaged membranes and stains the cells red (arrow A).…”

Section: Resultsmentioning

confidence: 99%

Biofilm formation by Candida albicans isolated from intrauterine devices

et al. 2008

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Our survey revealed that infected intrauterine devices (IUDs) recovered from patients suffering from reproductive tract infections (RTIs) were tainted with Candida biofi lm composed of a single or multiple species. Scanning electron microscopy (SEM) analysis of C. albicans biofi lm topography showed that it consists of a dense network of mono-or multilayer of cells embedded within the matrix of extracellular polymeric substances (EPS). Confocal scanning laser microscopy (CSLM) and atomic force microscopy (AFM) images depicted that C. albicans biofi lms have a highly heterogeneous architecture composed of cellular and noncellular elements with EPS distributed in the cell-surface periphery or at cell-cell interface. Biochemical analysis showed that EPS produced by C. albicans biofi lm contained signifi cantly reduced total carbohydrate (40%), protein (5%) and enhanced amount of hexosamine (4%) in contrast to its planktonic counterparts. The in vitro activity of antifungal agents amphotericin B, nystatin, fl uconazole and chlorhexidine against pre-formed C. albicans biofi lm, assessed using XTT (2,3-bis[2-methoxy-4-nitro-5-sulfophenyl]-2H-tetrazolium-5-carboxanilide) reduction assay revealed increased resistance of these infectious biofi lm (50% reduction in metabolic activity at a concentration of 8, 16, 64, 128 μg/ml respectively) in comparison to its planktonic form.

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“…The force generating a hydrophobic bond is approximately 20 pN (488), while the forces required to maintain stereospecific lectin-CHO binding range from 50 to 120 pN (608). With the development of force spectroscopy, forces between cells or purified adhesins and individual molecules can be reasonably accurately determined (609). This methodology provides a new means for comparative analyses of adhesin-receptor interactions.…”

Section: Adherence Forcesmentioning

confidence: 99%

StreptococcusAdherence and Colonization

Nobbs

Lamont

Jenkinson

2009

Microbiol Mol Biol Rev

547

569

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SUMMARY Streptococci readily colonize mucosal tissues in the nasopharynx; the respiratory, gastrointestinal, and genitourinary tracts; and the skin. Each ecological niche presents a series of challenges to successful colonization with which streptococci have to contend. Some species exist in equilibrium with their host, neither stimulating nor submitting to immune defenses mounted against them. Most are either opportunistic or true pathogens responsible for diseases such as pharyngitis, tooth decay, necrotizing fasciitis, infective endocarditis, and meningitis. Part of the success of streptococci as colonizers is attributable to the spectrum of proteins expressed on their surfaces. Adhesins enable interactions with salivary, serum, and extracellular matrix components; host cells; and other microbes. This is the essential first step to colonization, the development of complex communities, and possible invasion of host tissues. The majority of streptococcal adhesins are anchored to the cell wall via a C-terminal LPxTz motif. Other proteins may be surface anchored through N-terminal lipid modifications, while the mechanism of cell wall associations for others remains unclear. Collectively, these surface-bound proteins provide Streptococcus species with a “coat of many colors,” enabling multiple intimate contacts and interplays between the bacterial cell and the host. In vitro and in vivo studies have demonstrated direct roles for many streptococcal adhesins as colonization or virulence factors, making them attractive targets for therapeutic and preventive strategies against streptococcal infections. There is, therefore, much focus on applying increasingly advanced molecular techniques to determine the precise structures and functions of these proteins, and their regulatory pathways, so that more targeted approaches can be developed.

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Nanoscale Characterization and Determination of Adhesion Forces of Pseudomonas aeruginosa Pili by Using Atomic Force Microscopy

Cited by 151 publications

References 35 publications

Force-dependent polymorphism in type IV pili reveals hidden epitopes

Force-dependent polymorphism in type IV pili reveals hidden epitopes

Biofilm formation by Candida albicans isolated from intrauterine devices

StreptococcusAdherence and Colonization

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