scholarly journals Bacteria defend against phages through type IV pilus glycosylation

2017 ◽  
Author(s):  
Hanjeong Harvey ◽  
Joseph Bondy-Denomy ◽  
Hélène Marquis ◽  
Kristina M. Sztanko ◽  
Alan R. Davidson ◽  
...  
Keyword(s):  
Binding Sites ◽  
Opportunistic Pathogen ◽  
Surface Structures ◽  
Major Type ◽  
Post Translational Modification ◽  
Bacterial Surface ◽  
Specific Phage ◽  
Type Iv ◽  
Type Iv Pilin ◽  
Tail Proteins

ABSTRACTBacterial surface structures such as type IV pili are common receptors for phage. Strains of the opportunistic pathogenPseudomonas aeruginosaexpress one of five different major type IV pilin alleles, two of which are glycosylated with either lipopolysaccharide O-antigen units or polymers of D-arabinofuranose. Here we show that both these post-translational modifications protectP. aeruginosafrom a variety of pilus-specific phages. We identified a phage capable of infecting strains expressing both non-glycosylated and glycosylated pilins, and through construction of a chimeric phage, traced this ability to its unique tail proteins. Alteration of pilin sequence, or masking of binding sites by glycosylation, both block phage infection. The energy invested by prokaryotes in glycosylating thousands of pilin subunits is thus explained by the protection against phage predation provided by these common decorations.SIGNIFICANCEPost-translational modification of bacterial and archaeal surface structures such as pili and flagella is widespread, but the function of these decorations is not clear. We propose that predation by bacteriophages that use these structures as receptors selects for strains that mask potential phage binding sites using glycosylation. Phages are of significant interest as alternative treatments for antibiotic-resistant pathogens, but the ways in which phage interact with host receptors are not well understood. We show that specific phage tail proteins allow for infection of strains with glycosylated pili, providing a foundation for the creation of designer phages that can circumvent first-line bacterial defenses.

scholarly journals Differential interaction forces govern bacterial sorting in early biofilms

eLife ◽  
2015 ◽  
Vol 4 ◽  
Author(s):  
Enno R Oldewurtel ◽  
Nadzeya Kouzel ◽  
Lena Dewenter ◽  
Katja Henseler ◽  
Berenike Maier
Keyword(s):  
Cell Sorting ◽  
Cell Interaction ◽  
Surface Structures ◽  
Post Translational Modification ◽  
Bacterial Surface ◽  
Type Iv ◽  
Active Force Generation ◽  
Remarkable Agreement ◽  
Physical Principles ◽  
Strength Of Adhesion

Bacterial biofilms can generate micro-heterogeneity in terms of surface structures. However, little is known about the associated changes in the physics of cell–cell interaction and its impact on the architecture of biofilms. In this study, we used the type IV pilus of Neisseria gonorrhoeae to test whether variation of surface structures induces cell-sorting. We show that the rupture forces between pili are fine-tuned by post-translational modification. Bacterial sorting was dependent on pilus post-translational modification and pilus density. Active force generation was necessary for defined morphologies of mixed microcolonies. The observed morphotypes were in remarkable agreement with the differential strength of adhesion hypothesis proposing that a tug-of-war among surface structures of different cells governs cell sorting. We conclude that in early biofilms the density and rupture force of bacterial surface structures can trigger cell sorting based on similar physical principles as in developing embryos.

scholarly journals Type IV pilin post-translational modifications modulate materials properties of bacterial colonies

2018 ◽  
Author(s):  
R. Zöllner ◽  
T. Cronenberg ◽  
N. Kouzel ◽  
A. Welker ◽  
M. Koomey ◽  
...  
Keyword(s):  
Local Order ◽  
Glycan Structure ◽  
Post Translational Modification ◽  
Extracellular Polymers ◽  
Post Translational Modifications ◽  
Materials Properties ◽  
Type Iv ◽  
Pilin Subunit ◽  
Type Iv Pilin ◽  
Bacterial Type

AbstractBacterial type 4 pili (T4P) are extracellular polymers that initiate the formation of microcolonies and biofilms. T4P continuously elongate and retract. These pilus dynamics crucially affects the local order, shape, and fluidity of microcolonies. The major pilin subunit of the T4P bears multiple post-translational modifications. By interfering with different steps of the pilin glycosylation and phosphoform modification pathways, we investigated the effect of pilin post-translational modification on the shape and dynamics of microcolonies formed by Neisseria gonorrhoeae. Deleting the phosphotransferase responsible for phosphoethanolamine modification at residue serine 68 (S68) inhibits shape relaxations of microcolonies after pertubation and causes bacteria carrying the phosphoform modification to segregate to the surface of mixed colonies. We relate these mesoscopic phenotypes to increased attractive forces generated by T4P between cells. Moreover, by deleting genes responsible for the pilin glycan structure, we show that the number of saccharides attached at residue serine 63 (S63) affect the ratio between surface tension and viscosity and cause sorting between bacteria carrying different pilin glycoforms. We conclude that different pilin post-translational modifications moderately affect the attractive forces between bacteria but have severe effects on the materials properties of microcolonies.

scholarly journals Eikenella corrodens Phase Variation Involves a Posttranslational Event in Pilus Formation

1999 ◽  
Vol 181 (14) ◽  
pp. 4154-4160 ◽  
Author(s):  
Maria T. Villar ◽  
Jennifer T. Helber ◽  
Becky Hood ◽  
Michael R. Schaefer ◽  
Rona L. Hirschberg
Keyword(s):  
Sequence Analysis ◽  
Phase Variation ◽  
S Phase ◽  
Open Reading Frames ◽  
Major Type ◽  
Eikenella Corrodens ◽  
Dichelobacter Nodosus ◽  
Type Iv ◽  
Type Iv Pilin ◽  
Phase Variants

ABSTRACT The human pathogen Eikenella corrodens synthesizes type IV pili and exhibits a phase variation involving the irreversible transition from piliated to nonpiliated variants. On solid medium, piliated variants form small (S-phase), corroding colonies whereas nonpiliated variants form large (L-phase), noncorroding colonies. We are studying the molecular basis of this phase variation in the clinical isolate E. corrodens VA1. A genomic fragment encoding the major type IV pilin was cloned from the S-phase variant of strain VA1. Sequence analysis of the fragment revealed four tandemly arranged potential open reading frames (ORFs), designatedpilA1, pilA2, pilB, andhagA. Both pilA1 and pilA2 predict a type IV pilin. The protein predicted by pilB shares sequence identity with the Dichelobacter nodosus FimB fimbrial assembly protein. The protein predicted by hagAresembles a hemagglutinin. The region containing these four ORFs was designated the pilA locus. DNA hybridization and sequence analysis showed that the pilA locus of an L-phase variant of strain VA1 was identical to that of the S-phase variant. An abundantpilA1 transcript initiating upstream of pilA1and terminating at a predicted hairpin structure betweenpilA1 and pilA2 was detected by several assays, as was a less abundant read-through transcript encompassingpilA1, pilA2, and pilB. Transcription from the pilA locus was nearly indistinguishable between S- and L-phase variants. Electron microscopy and immunochemical analysis showed that S-phase variants synthesize, export, and assemble pilin into pili. In contrast, L-phase variants synthesize pilin but do not export and assemble it into pili. These data suggest that a posttranslational event, possibly involving an alteration in pilin export and assembly, is responsible for phase variation in E. corrodens.

scholarly journals The effect of Quorum sensing inhibitors on the evolution of CRISPR-based phage immunity in Pseudomonas aeruginosa

2021 ◽  
Author(s):  
Jenny M. Broniewski ◽  
Matthew A. W. Chisnall ◽  
Nina Molin Høyland-Kroghsbo ◽  
Angus Buckling ◽  
Edze R. Westra
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Quorum Sensing ◽  
Evolutionary Dynamics ◽  
Opportunistic Pathogen ◽  
Specific Phage ◽  
Type Iv ◽  
Quorum Sensing Inhibitors ◽  
Wide Range ◽  
Chemical Inhibition ◽  
Adsorption Rates

AbstractQuorum sensing controls the expression of a wide range of important traits in the opportunistic pathogen Pseudomonas aeruginosa, including the expression of virulence genes and its CRISPR-cas immune system, which protects from bacteriophage (phage) infection. This finding has led to the speculation that synthetic quorum sensing inhibitors could be used to limit the evolution of CRISPR immunity during phage therapy. Here we use experimental evolution to explore if and how a quorum sensing inhibitor influences the population and evolutionary dynamics of P. aeruginosa upon phage DMS3vir infection. We find that chemical inhibition of quorum sensing decreases phage adsorption rates due to downregulation of the Type IV pilus, which causes delayed lysis of bacterial cultures and favours the evolution of CRISPR immunity. Our data therefore suggest that inhibiting quorum sensing may reduce rather than improve the therapeutic efficacy of pilus-specific phage, and this is likely a general feature when phage receptors are positively regulated by quorum sensing.

Neurofilament Proteins as Prognostic Biomarkers in Neurological Disorders

2020 ◽  
Vol 25 (43) ◽  
pp. 4560-4569 ◽  
Author(s):  
Yichen Lee ◽  
Bo H. Lee ◽  
William Yip ◽  
Pingchen Chou ◽  
Bak-Sau Yip
Keyword(s):  
Amyotrophic Lateral Sclerosis ◽  
Nervous System ◽  
Trinucleotide Repeat ◽  
Muscular Atrophy ◽  
Electric Signal ◽  
Motor Neuropathy ◽  
Post Translational Modification ◽  
Neurofilament Proteins ◽  
Type Iv ◽  
Lateral Sclerosis

Neurofilaments: light, medium, and heavy (abbreviated as NF-L, NF-M, and NF-H, respectively), which belong to Type IV intermediate filament family (IF), are neuron-specific cytoskeletal components. Neurofilaments are axonal structural components and integral components of synapses, which are important for neuronal electric signal transmissions along the axons and post-translational modification. Abnormal assembly of neurofilaments is found in several human neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), infantile spinal muscular atrophy (SMA), and hereditary sensory-motor neuropathy (HSMN). In addition, those pathological neurofilament accumulations are known in α-synuclein in Parkinson’s disease (PD), Aβ and tau in Alzheimer’s disease (AD), polyglutamine in CAG trinucleotide repeat disorders, superoxide dismutase 1 (SOD1), TAR DNA-binding protein 43 (TDP43), neuronal FUS proteins, optineurin (OPTN), ubiquilin 2 (UBQLN2), and dipeptide repeat protein (DRP) in amyotrophic lateral sclerosis (ALS). When axon damage occurs in central nervous disorders, neurofilament proteins are released and delivered into cerebrospinal fluid (CSF), which are then circulated into blood. New quantitative analyses and assay techniques are well-developed for the detection of neurofilament proteins, particularly NF-L and the phosphorylated NF-H (pNF-H) in CSF and serum. This review discusses the potential of using peripheral blood NF quantities and evaluating the severity of damage in the nervous system. Intermediate filaments could be promising biomarkers for evaluating disease progression in different nervous system disorders.

scholarly journals Protein Nanowires: the Electrification of the Microbial World and Maybe Our Own

2020 ◽  
Vol 202 (20) ◽  
Author(s):  
Derek R. Lovley ◽  
Dawn E. Holmes
Keyword(s):  
Electron Transport ◽  
Long Range ◽  
Electronic Devices ◽  
Electricity Production ◽  
Microbial World ◽  
Electrically Conductive ◽  
Anaerobic Digesters ◽  
Content Type ◽  
Type Iv ◽  
Type Iv Pilin

ABSTRACT Electrically conductive protein nanowires appear to be widespread in the microbial world and are a revolutionary “green” material for the fabrication of electronic devices. Electrically conductive pili (e-pili) assembled from type IV pilin monomers have independently evolved multiple times in microbial history as have electrically conductive archaella (e-archaella) assembled from homologous archaellin monomers. A role for e-pili in long-range (micrometer) extracellular electron transport has been demonstrated in some microbes. The surprising finding of e-pili in syntrophic bacteria and the role of e-pili as conduits for direct interspecies electron transfer have necessitated a reassessment of routes for electron flux in important methanogenic environments, such as anaerobic digesters and terrestrial wetlands. Pilin monomers similar to those found in e-pili may also be a major building block of the conductive “cables” that transport electrons over centimeter distances through continuous filaments of cable bacteria consisting of a thousand cells or more. Protein nanowires harvested from microbes have many functional and sustainability advantages over traditional nanowire materials and have already yielded novel electronic devices for sustainable electricity production, neuromorphic memory, and sensing. e-pili can be mass produced with an Escherichia coli chassis, providing a ready source of material for electronics as well as for studies on the basic mechanisms for long-range electron transport along protein nanowires. Continued exploration is required to better understand the electrification of microbial communities with microbial nanowires and to expand the “green toolbox” of sustainable materials for wiring and powering the emerging “Internet of things.”

The use of cationized ferritin as an ultrastructural stain for the visualization of bacterial surface structures by SEM

1987 ◽  
Vol 23 (2) ◽  
pp. 252
Author(s):  
Jenny Naimark ◽  
Eli Morgenstern ◽  
Edward A. Bayer ◽  
Raphael Lamed
Keyword(s):  
Surface Structures ◽  
Cationized Ferritin ◽  
Bacterial Surface

scholarly journals Disparate Subcellular Localization Patterns of Pseudomonas aeruginosa Type IV Pilus ATPases Involved in Twitching Motility

2005 ◽  
Vol 187 (3) ◽  
pp. 829-839 ◽  
Author(s):  
Poney Chiang ◽  
Marc Habash ◽  
Lori L. Burrows
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Fluorescent Protein ◽  
Protein Localization ◽  
Yellow Fluorescent Protein ◽  
Distribution Patterns ◽  
Opportunistic Pathogen ◽  
Twitching Motility ◽  
Polar Localization ◽  
Type Iv ◽  
And Function

ABSTRACT The opportunistic pathogen Pseudomonas aeruginosa expresses polar type IV pili (TFP), which are responsible for adhesion to various materials and twitching motility on surfaces. Twitching occurs by alternate extension and retraction of TFP, which arise from assembly and disassembly of pilin subunits at the base of the pilus. The ATPase PilB promotes pilin assembly, while the ATPase PilT or PilU or both promote pilin dissociation. Fluorescent fusions to two of the three ATPases (PilT and PilU) were functional, as shown by complementation of the corresponding mutants. PilB and PilT fusions localized to both poles, while PilU fusions localized only to the piliated pole. To identify the portion of the ATPases required for localization, sequential C-terminal deletions of PilT and PilU were generated. The conserved His and Walker B boxes were dispensable for polar localization but were required for twitching motility, showing that localization and function could be uncoupled. Truncated fusions that retained polar localization maintained their distinctive distribution patterns. To dissect the cellular factors involved in establishing polarity, fusion protein localization was monitored with a panel of TFP mutants. The localization of yellow fluorescent protein (YFP)-PilT and YFP-PilU was independent of the subunit PilA, other TFP ATPases, and TFP-associated proteins previously shown to be associated with the membrane or exhibiting polar localization. In contrast, YFP-PilB exhibited diffuse cytoplasmic localization in a pilC mutant, suggesting that PilC is required for polar localization of PilB. Finally, localization studies performed with fluorescent ATPase chimeras of PilT and PilU demonstrated that information responsible for the characteristic localization patterns of the ATPases likely resides in their N termini.

scholarly journals Single-Residue Changes in the C-Terminal Disulfide-Bonded Loop of the Pseudomonas aeruginosa Type IV Pilin Influence Pilus Assembly and Twitching Motility

2009 ◽  
Vol 191 (21) ◽  
pp. 6513-6524 ◽  
Author(s):  
Hanjeong Harvey ◽  
Marc Habash ◽  
Francisca Aidoo ◽  
Lori L. Burrows
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antigenic Variation ◽  
Intact Protein ◽  
Twitching Motility ◽  
Beta Turn ◽  
Type Iv ◽  
Pilin Subunit ◽  
Type Iv Pilin ◽  
Intersubunit Interactions ◽  
Pilus Assembly

ABSTRACT PilA, the major pilin subunit of Pseudomonas aeruginosa type IV pili (T4P), is a principal structural component. PilA has a conserved C-terminal disulfide-bonded loop (DSL) that has been implicated as the pilus adhesinotope. Structural studies have suggested that DSL is involved in intersubunit interactions within the pilus fiber. PilA mutants with single-residue substitutions, insertions, or deletions in the DSL were tested for pilin stability, pilus assembly, and T4P function. Mutation of either Cys residue of the DSL resulted in pilins that were unable to assemble into fibers. Ala replacements of the intervening residues had a range of effects on assembly or function, as measured by changes in surface pilus expression and twitching motility. Modification of the C-terminal P-X-X-C type II beta-turn motif, which is one of the few highly conserved features in pilins across various species, caused profound defects in assembly and twitching motility. Expression of pilins with suspected assembly defects in a pilA pilT double mutant unable to retract T4P allowed us to verify which subunits were physically unable to assemble. Use of two different PilA antibodies showed that the DSL may be an immunodominant epitope in intact pili compared with pilin monomers. Sequence diversity of the type IVa pilins likely reflects an evolutionary compromise between retention of function and antigenic variation. The consequences of DSL sequence changes should be evaluated in the intact protein since it is technically feasible to generate DSL-mimetic peptides with mutations that will not appear in the natural repertoire due to their deleterious effects on assembly.

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