scholarly journals Characterization of Adhesion Threads of Deinococcus geothermalis as Type IV Pili

2006 ◽  
Vol 188 (19) ◽  
pp. 7016-7021 ◽  
Author(s):  
C. Saarimaa ◽  
M. Peltola ◽  
M. Raulio ◽  
T. R. Neu ◽  
M. S. Salkinoja-Salonen ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Periodic Acid ◽  
Bacterial Attachment ◽  
Extracellular Proteins ◽  
Type Iv Pili ◽  
Confocal Laser ◽  
Major Protein ◽  
Paper Machine ◽  
Type Iv ◽  
Deinococcus Geothermalis

ABSTRACT Deinococcus geothermalis E50051 forms tenuous biofilms on paper machine surfaces. Field emission electron microscopy analysis revealed peritrichous appendages which mediated cell-to-surface and cell-to-cell interactions but were absent in planktonically grown cells. The major protein component of the extracellular extract of D. geothermalis had an N-terminal sequence similar to the fimbrial protein pilin annotated in the D. geothermalis DSM 11300 draft sequence. It also showed similarity to the type IV pilin sequence of D. radiodurans and several gram-negative pathogenic bacteria. Other proteins in the extract had N-terminal sequences identical to D. geothermalis proteins with conservative motifs for serine proteases, metallophosphoesterases, and proteins whose function is unknown. Periodic acid-Schiff staining for carbohydrates indicated that these extracellular proteins may be glycosylated. A further confirmation for the presence of glycoconjugates on the cell surface was obtained by confocal laser scanning imaging of living D. geothermalis cells stained with Amaranthus caudatus lectin, which specifically binds to galactose residues. The results indicate that the thread-like appendages of D. geothermalis E50051 are glycosylated type IV pili, bacterial attachment organelles which have thus far not been described for the genus Deinococcus.

scholarly journals Involvement of Type IV Pili in Pathogenicity of Plant Pathogenic Bacteria

Genes ◽  
2011 ◽  
Vol 2 (4) ◽  
pp. 706-735 ◽  
Author(s):  
Saul Burdman ◽  
Ofir Bahar ◽  
Jennifer K. Parker ◽  
Leonardo De La Fuente
Keyword(s):  
Pathogenic Bacteria ◽  
Type Iv Pili ◽  
Plant Pathogenic Bacteria ◽  
Type Iv

scholarly journals Fresh extension of Vibrio cholerae competence type IV pili predisposes them for motor-independent retraction

2021 ◽  
Author(s):  
Jennifer L. Chlebek ◽  
Triana N. Dalia ◽  
Nicolas Biais ◽  
Ankur B. Dalia
Keyword(s):  
Cell Surface ◽  
Vibrio Cholerae ◽  
Conformational Changes ◽  
Pathogenic Bacteria ◽  
Ectopic Expression ◽  
Type Iv Pili ◽  
Therapeutic Interventions ◽  
Dynamic Activity ◽  
Type Iv ◽  
Additional Support

ABSTRACTBacteria utilize dynamic appendages called type IV pili (T4P) to interact with their environment and mediate a wide variety of functions. Pilus extension is mediated by an extension ATPase motor, commonly called PilB, in all T4P. Pilus retraction, however, can either occur with the aid of an ATPase motor, or in the absence of a retraction motor. While much effort has been devoted to studying motor-dependent retraction, the mechanism and regulation of motor-independent retraction remains poorly characterized. We have previously demonstrated that Vibrio cholerae competence T4P undergo motor-independent retraction in the absence of the dedicated retraction ATPases PilT and PilU. Here, we utilize this model system to characterize the factors that influence motor-independent retraction. We find that freshly extended pili frequently undergo motor-independent retraction, but if these pili fail to retract immediately, they remain statically extended on the cell surface. Importantly, we show that these static pili can still undergo motor-dependent retraction via tightly regulated ectopic expression of PilT, suggesting that these T4P are not broken, but simply cannot undergo motor-independent retraction. Through additional genetic and biophysical characterization of pili, we suggest that pilus filaments undergo conformational changes during dynamic extension and retraction. We propose that only some conformations, like those adopted by freshly extended pili, are capable of undergoing motor-independent retraction. Together, these data highlight the versatile mechanisms that regulate T4P dynamic activity and provide additional support for the long-standing hypothesis that motor-independent retraction occurs via spontaneous depolymerization.SIGNIFICANCEExtracellular pilus fibers are critical to the virulence and persistence of many pathogenic bacteria. A crucial function for most pili is the dynamic ability to extend and retract from the cell surface. Inhibiting this dynamic pilus activity represents an attractive approach for therapeutic interventions, however, a detailed mechanistic understanding of this process is currently lacking. Here, we use the competence pilus of Vibrio cholerae to study how pili retract in the absence of dedicated retraction motors. Our results reveal a novel regulatory mechanism of pilus retraction that is an inherent property of the external pilus filament. Thus, understanding the conformational changes that pili adopt under different conditions may be critical for the development of novel therapeutics that aim to target the dynamic activity of these structures.

scholarly journals Structure and function of minor pilins of type IV pili

2019 ◽  
Vol 209 (3) ◽  
pp. 301-308 ◽  
Author(s):  
Theis Jacobsen ◽  
Benjamin Bardiaux ◽  
Olivera Francetic ◽  
Nadia Izadi-Pruneyre ◽  
Michael Nilges
Keyword(s):  
Pathogenic Bacteria ◽  
Type Iv Pili ◽  
Host Cells ◽  
Type Ii Secretion ◽  
Type Iv Pilus ◽  
Type Iv ◽  
Flexible Fibers ◽  
Multiple Copies ◽  
Species Specific ◽  
And Function

AbstractType IV pili are versatile and highly flexible fibers formed on the surface of many Gram-negative and Gram-positive bacteria. Virulence and infection rate of several pathogenic bacteria, such as Neisseria meningitidis and Pseudomonas aeruginosa, are strongly dependent on the presence of pili as they facilitate the adhesion of the bacteria to the host cell. Disruption of the interactions between the pili and the host cells by targeting proteins involved in this interaction could, therefore, be a treatment strategy. A type IV pilus is primarily composed of multiple copies of protein subunits called major pilins. Additional proteins, called minor pilins, are present in lower abundance, but are essential for the assembly of the pilus or for its specific functions. One class of minor pilins is required to initiate the formation of pili, and may form a complex similar to that identified in the related type II secretion system. Other, species-specific minor pilins in the type IV pilus system have been shown to promote additional functions such as DNA binding, aggregation and adherence. Here, we will review the structure and the function of the minor pilins from type IV pili.

scholarly journals Expression of Type IV Pili by Moraxella catarrhalis Is Essential for Natural Competence and Is Affected by Iron Limitation

2004 ◽  
Vol 72 (11) ◽  
pp. 6262-6270 ◽  
Author(s):  
Nicole R. Luke ◽  
Amy J. Howlett ◽  
Jianqiang Shao ◽  
Anthony A. Campagnari
Keyword(s):  
Moraxella Catarrhalis ◽  
Pathogenic Bacteria ◽  
Type Iv Pili ◽  
Protein Subunit ◽  
Electron Microscopic ◽  
Type Iv ◽  
Wide Range ◽  
Genes Encoding ◽  
Microscopic Studies

ABSTRACT Type IV pili, filamentous surface appendages primarily composed of a single protein subunit termed pilin, play a crucial role in the initiation of disease by a wide range of pathogenic bacteria. Although previous electron microscopic studies suggested that pili might be present on the surface of Moraxella catarrhalis isolates, detailed molecular and phenotypic analyses of these structures have not been reported to date. We identified and cloned the M. catarrhalis genes encoding PilA, the major pilin subunit, PilQ, the outer membrane secretin through which the pilus filament is extruded, and PilT, the NTPase that mediates pilin disassembly and retraction. To initiate investigation of the role of this surface organelle in pathogenesis, isogenic pilA, pilT, and pilQ mutants were constructed in M. catarrhalis strain 7169. Comparative analyses of the wild-type 7169 strain and three isogenic pil mutants demonstrated that M. catarrhalis expresses type IV pili that are essential for natural genetic transformation. Our studies suggest type IV pilus production by M. catarrhalis is constitutive and ubiquitous, although pilin expression was demonstrated to be iron responsive and Fur regulated. These data indicate that additional studies aimed at elucidating the prevalence and role of type IV pili in the pathogenesis and host response to M. catarrhalis infections are warranted.

scholarly journals Fresh extension of Vibrio cholerae competence type IV pili predisposes them for motor-independent retraction

2021 ◽  
Author(s):  
Jennifer L. Chlebek ◽  
Triana N. Dalia ◽  
Nicolas Biais ◽  
Ankur B. Dalia
Keyword(s):  
Cell Surface ◽  
Vibrio Cholerae ◽  
Conformational Changes ◽  
Pathogenic Bacteria ◽  
Ectopic Expression ◽  
Type Iv Pili ◽  
Therapeutic Interventions ◽  
Dynamic Activity ◽  
Type Iv ◽  
Additional Support

Bacteria utilize dynamic appendages called type IV pili (T4P) to interact with their environment and mediate a wide variety of functions. Pilus extension is mediated by an extension ATPase motor, commonly called PilB, in all T4P. Pilus retraction, however, can either occur with the aid of an ATPase motor, or in the absence of a retraction motor. While much effort has been devoted to studying motor-dependent retraction, the mechanism and regulation of motor-independent retraction remains poorly characterized. We have previously demonstrated that Vibrio cholerae competence T4P undergo motor-independent retraction in the absence of the dedicated retraction ATPases PilT and PilU. Here, we utilize this model system to characterize the factors that influence motor-independent retraction. We find that freshly extended pili frequently undergo motor-independent retraction, but if these pili fail to retract immediately, they remain statically extended on the cell surface. Importantly, we show that these static pili can still undergo motor-dependent retraction via tightly regulated ectopic expression of PilT, suggesting that these T4P are not broken, but simply cannot undergo motor-independent retraction. Through additional genetic and biophysical characterization of pili, we suggest that pilus filaments undergo conformational changes during dynamic extension and retraction. We propose that only some conformations, like those adopted by freshly extended pili, are capable of undergoing motor-independent retraction. Together, these data highlight the versatile mechanisms that regulate T4P dynamic activity and provide additional support for the long-standing hypothesis that motor-independent retraction occurs via spontaneous depolymerization. IMPORTANCE Extracellular pilus fibers are critical to the virulence and persistence of many pathogenic bacteria. A crucial function for most pili is the dynamic ability to extend and retract from the cell surface. Inhibiting this dynamic pilus activity represents an attractive approach for therapeutic interventions, however, a detailed mechanistic understanding of this process is currently lacking. Here, we use the competence pilus of Vibrio cholerae to study how pili retract in the absence of dedicated retraction motors. Our results reveal a novel regulatory mechanism of pilus retraction that is an inherent property of the pilus filament. Thus, understanding the conformational changes that pili adopt under different conditions may be critical for the development of novel therapeutics that aim to target the dynamic activity of these structures.

scholarly journals Surface plasmon resonance shows that type IV pili are important in surface attachment by Pseudomonas aeruginosa

2005 ◽  
Vol 2 (3) ◽  
pp. 255-259 ◽  
Author(s):  
A. Toby A Jenkins ◽  
Angus Buckling ◽  
Marsha McGhee ◽  
Richard H ffrench-Constant
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Surface Plasmon Resonance ◽  
Real Time ◽  
Surface Plasmon ◽  
Plasmon Resonance ◽  
Bacterial Attachment ◽  
Type Iv Pili ◽  
Bacterial Biofilm ◽  
Analytical Technique ◽  
Type Iv

Type IV pili have been shown to play a role in the early stages of bacterial biofilm formation, but not in initial bacterial attachment. Here, using the surface analytical technique, surface plasmon resonance (SPR), we follow the attachment of the bacterium Pseudomonas aeruginosa in real time. In contrast to previous studies, we show that type IV pili mutants are defective in attachment. Both mutants lacking pili ( pilA ), and those possessing an overabundance of pili ( pilT ), showed reduced SPR measured attachment compared with the wild-type PAO1 strain. Both pil mutants also showed reduced pathogenicity in a model insect host, as measured by percentage mortality after 24 h. SPR revealed differences in the kinetics of attachment between pilA and pilT , differences obscured by endpoint assays using crystal violet stain. These results highlight the power of SPR in monitoring bacterial attachment in real time and also demonstrate an additional role for type IV pili beyond bacterial aggregation and micro-colony formation.

scholarly journals Analysis of Pathogen-Host Cell Interactions in Purpura Fulminans: Expression of Capsule, Type IV Pili, and PorA by Neisseria meningitidis In Vivo

2002 ◽  
Vol 70 (9) ◽  
pp. 5193-5201 ◽  
Author(s):  
O. B. Harrison ◽  
B. D. Robertson ◽  
S. N. Faust ◽  
M. A. Jepson ◽  
R. D. Goldin ◽  
...  
Keyword(s):  
Purpura Fulminans ◽  
Phase Variation ◽  
Type Iv Pili ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Inflammatory Cell Infiltrate ◽  
Immunoperoxidase Staining ◽  
Capsule Type ◽  
Type Iv

ABSTRACT The pattern of meningococcal surface structure expression in different microenvironments following bloodstream invasion in vivo is not known. We used immunohistochemistry to determine the expression of capsule, type IV pili, and PorA by meningococci residing in the skin lesions of children with purpura fulminans. All the skin biopsy samples showed evidence of thrombosis and, frequently, a perivascular inflammatory cell infiltrate consisting of neutrophils (elastase positive) and monocytes/macrophages (CD68 positive). Modified Gram staining revealed 20 to over 100 gram-negative diplococci in each 4-μm-thick section, usually grouped into microcolonies. Immunoperoxidase staining demonstrated that the invading meningococci expressed PorA, capsule, and type IV pilin. Expression of these antigens was not restricted to any particular environment and was found in association with meningococci located in leukocytes, small blood vessels, and the dermal interstitium. Confocal laser scanning microscopy demonstrated coexpression of pilin and capsule by numerous microcolonies. However, there was some discordance in capsule and pilin expression within the microcolonies, suggesting phase variation. The strategy employed in this study will be helpful in investigating invasive bacterial diseases where antigenic and phase variation has a significant impact on virulence and on vaccine design.

Biodegradable polyester neuroprostheses promote the reconnection of separated peripheral nerve stubs

1992 ◽  
Vol 50 (2) ◽  
pp. 1094-1095
Author(s):  
Beverly L. Giammara ◽  
Jennifer S. Stevenson ◽  
Peggy E. Yates ◽  
Robert H. Gunderson ◽  
Jacob S. Hanker
Keyword(s):  
Image Analysis ◽  
Basement Membrane ◽  
Periodic Acid ◽  
Light And Electron Microscopy ◽  
Computer Assisted ◽  
Type Iii Collagen ◽  
Image Analysis System ◽  
Biodegradable Polyester ◽  
Adult Rats ◽  
Type Iv

An 11mm length of sciatic nerve was removed from 10 anesthetized adult rats and replaced by a biodegradable polyester Vicryl™ mesh sleeve which was then injected with the basement membrane gel, Matrigel™. It was noted that leg sensation and movement were much improved after 30 to 45 days and upon sacrifice nerve reconnection was noted in all animals. Epoxy sections of the repaired nerves were compared with those of the excised segments by the use of a variation of the PAS reaction, the PATS reaction, developed in our laboratories for light and electron microscopy. This microwave-accelerated technique employs periodic acid, thiocarbohydrazide and silver methenamine. It stains basement membrane or Type IV collagen brown and type III collagen (reticulin), axons, Schwann cells, endoneurium and perineurium black. Epoxy sections of repaired and excised nerves were also compared by toluidine blue (tb) staining. Comparison of the sections of control and repaired nerves was done by computer-assisted microscopic image analysis using an Olympus CUE-2 Image Analysis System.

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