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Nature Reviews. Microbiology Jun 2015Bacteria have evolved a remarkable array of sophisticated nanomachines to export various virulence factors across the bacterial cell envelope. In recent years,... (Review)
Review
Bacteria have evolved a remarkable array of sophisticated nanomachines to export various virulence factors across the bacterial cell envelope. In recent years, considerable progress has been made towards elucidating the structural and molecular mechanisms of the six secretion systems (types I-VI) of Gram-negative bacteria, the unique mycobacterial type VII secretion system, the chaperone-usher pathway and the curli secretion machinery. These advances have greatly enhanced our understanding of the complex mechanisms that these macromolecular structures use to deliver proteins and DNA into the extracellular environment or into target cells. In this Review, we explore the structural and mechanistic relationships between these single- and double-membrane-embedded systems, and we briefly discuss how this knowledge can be exploited for the development of new antimicrobial strategies.
Topics: Anti-Bacterial Agents; Bacterial Secretion Systems; Cell Membrane; Fimbriae, Bacterial; Gram-Negative Bacteria; Gram-Negative Bacterial Infections; Molecular Chaperones; Virulence Factors
PubMed: 25978706
DOI: 10.1038/nrmicro3456 -
Nature Jun 2017Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) affect 150 million people annually. Despite effective antibiotic therapy, 30-50% of...
Urinary tract infections (UTIs) caused by uropathogenic Escherichia coli (UPEC) affect 150 million people annually. Despite effective antibiotic therapy, 30-50% of patients experience recurrent UTIs. In addition, the growing prevalence of UPEC that are resistant to last-line antibiotic treatments, and more recently to carbapenems and colistin, make UTI a prime example of the antibiotic-resistance crisis and emphasize the need for new approaches to treat and prevent bacterial infections. UPEC strains establish reservoirs in the gut from which they are shed in the faeces, and can colonize the periurethral area or vagina and subsequently ascend through the urethra to the urinary tract, where they cause UTIs. UPEC isolates encode up to 16 distinct chaperone-usher pathway pili, and each pilus type may enable colonization of a habitat in the host or environment. For example, the type 1 pilus adhesin FimH binds mannose on the bladder surface, and mediates colonization of the bladder. However, little is known about the mechanisms underlying UPEC persistence in the gut. Here, using a mouse model, we show that F17-like and type 1 pili promote intestinal colonization and show distinct binding to epithelial cells distributed along colonic crypts. Phylogenomic and structural analyses reveal that F17-like pili are closely related to pilus types carried by intestinal pathogens, but are restricted to extra-intestinal pathogenic E. coli. Moreover, we show that targeting FimH with M4284, a high-affinity inhibitory mannoside, reduces intestinal colonization of genetically diverse UPEC isolates, while simultaneously treating UTI, without notably disrupting the structural configuration of the gut microbiota. By selectively depleting intestinal UPEC reservoirs, mannosides could markedly reduce the rate of UTIs and recurrent UTIs.
Topics: Adhesins, Escherichia coli; Amino Acid Sequence; Animals; Epithelial Cells; Feces; Female; Fimbriae Proteins; Fimbriae, Bacterial; Humans; Intestines; Mannosides; Mice; Models, Molecular; Phthalic Acids; Urinary Bladder; Urinary Tract Infections; Uropathogenic Escherichia coli
PubMed: 28614296
DOI: 10.1038/nature22972 -
FEMS Microbiology Reviews Jan 2015Pseudomonads sense changes in the concentration of chemicals in their environment and exhibit a behavioral response mediated by flagella or pili coupled with a... (Review)
Review
Pseudomonads sense changes in the concentration of chemicals in their environment and exhibit a behavioral response mediated by flagella or pili coupled with a chemosensory system. The two known chemotaxis pathways, a flagella-mediated pathway and a putative pili-mediated system, are described in this review. Pseudomonas shows chemotaxis response toward a wide range of chemicals, and this review includes a summary of them organized by chemical structure. The assays used to measure positive and negative chemotaxis swimming and twitching Pseudomonas as well as improvements to those assays and new assays are also described. This review demonstrates that there is ample research and intellectual space for future investigators to elucidate the role of chemotaxis in important processes such as pathogenesis, bioremediation, and the bioprotection of plants and animals.
Topics: Chemotaxis; Fimbriae, Bacterial; Flagella; Pseudomonas
PubMed: 25100612
DOI: 10.1111/1574-6976.12081 -
Current Biology : CB Feb 2022In this Quick guide, Derek Lovley introduces microbial nanowires-conductive extracellular appendages made by some bacteria and archaea.
In this Quick guide, Derek Lovley introduces microbial nanowires-conductive extracellular appendages made by some bacteria and archaea.
Topics: Bacteria; Electric Conductivity; Electron Transport; Fimbriae, Bacterial; Nanowires
PubMed: 35134353
DOI: 10.1016/j.cub.2021.12.019 -
Sub-cellular Biochemistry 2018Escherichia coli bacterial cells produce multiple types of adhesion pili that mediate cell-cell and cell-host attachments. These pili (also called 'fimbriae') are large... (Review)
Review
Escherichia coli bacterial cells produce multiple types of adhesion pili that mediate cell-cell and cell-host attachments. These pili (also called 'fimbriae') are large biopolymers that are comprised of subunits assembled via a sophisticated micro-machinery into helix-like structures that are anchored in the bacterial outer membrane. They are commonly essential for initiation of disease and thus provide a potential target for antibacterial prevention and treatment. To develop new therapeutics for disease prevention and treatment we need to understand the molecular mechanisms and the direct role of adhesion pili during pathogenesis. These helix-like pilus structures possess fascinating and unique biomechanical properties that have been thoroughly investigated using high-resolution imaging techniques, force spectroscopy and fluid flow chambers. In this chapter, we first discuss the structure of pili and the micro-machinery responsible for the assembly process. Thereafter, we present methods for measurement of the biomechanics of adhesion pili, including optical tweezers. Data demonstrate unique biomechanical properties of pili that allow bacteria to sustain binding during in vivo fluid shear forces. We thereafter summarize the current biomechanical findings related to adhesion pili and show that pili biomechanical properties are niche-specific. That is, the data suggest that there is an organ-specific adaptation of pili that facilitates infection of the bacteria's target tissue. Thus, pilus biophysical properties are an important part of Escherichia coli pathogenesis, allowing bacteria to overcome hydrodynamic challenges in diverse environments.
Topics: Animals; Bacterial Adhesion; Escherichia coli; Escherichia coli Infections; Fimbriae, Bacterial; Humans
PubMed: 29464555
DOI: 10.1007/978-981-10-7757-9_1 -
Trends in Microbiology Apr 2020
Topics: Biodegradation, Environmental; Electricity; Electrodes; Electron Transport; Fimbriae Proteins; Fimbriae, Bacterial; Geobacter; Nanowires; Oxidation-Reduction; Peptide Fragments
PubMed: 31864843
DOI: 10.1016/j.tim.2019.11.004 -
Molecular Aspects of Medicine Oct 2021Surface pili (or fimbriae) are an important but conspicuous adaptation of several genera and species of Gram-negative and Gram-positive bacteria. These long and... (Review)
Review
Surface pili (or fimbriae) are an important but conspicuous adaptation of several genera and species of Gram-negative and Gram-positive bacteria. These long and non-flagellar multi-subunit adhesins mediate the initial contact that a bacterium has with a host or environment, and thus have come to be regarded as a key colonization factor for virulence activity in pathogens or niche adaptation in commensals. Pili in pathogenic bacteria are well recognized for their roles in the adhesion to host cells, colonization of tissues, and establishment of infection. As an 'anti-adhesive' ploy, targeting pilus-mediated attachment for disruption has become a potentially effective alternative to using antibiotics. In this review, we give a description of the several structurally distinct bacterial pilus types thus far characterized, and as well offer details about the intricacy of their individual structure, assembly, and function. With a molecular understanding of pilus biogenesis and pilus-mediated host interactions also provided, we go on to describe some of the emerging new approaches and compounds that have been recently developed to prevent the adhesion, colonization, and infection of piliated bacterial pathogens.
Topics: Fimbriae, Bacterial; Gram-Positive Bacteria; Humans
PubMed: 34294411
DOI: 10.1016/j.mam.2021.100998 -
Frontiers in Cellular and Infection... 2023The pilus is an extracellular structural part that can be detected in some () isolates (type I pili are found in approximately 30% of strains, while type II pili are... (Review)
Review
The pilus is an extracellular structural part that can be detected in some () isolates (type I pili are found in approximately 30% of strains, while type II pili are found in approximately 20%). It is anchored to the cell wall by LPXTG-like motifs on the peptidoglycan. Two kinds of pili have been discovered, namely, pilus-1 and pilus-2. The former is encoded by pilus islet 1 (PI-1) and is a polymer formed by the protein subunits RrgA, RrgB and RrgC. The latter is encoded by pilus islet 2 (PI-2) and is a polymer composed mainly of the structural protein PitB. Although pili are not necessary for the survival of , they serve as the structural basis and as virulence factors that mediate the adhesion of bacteria to host cells and play a direct role in promoting the adhesion, colonization and pathogenesis of . In addition, as candidate antigens for protein vaccines, pili have promising potential for use in vaccines with combined immunization strategies. Given the current understanding of the pili of regarding the genes, proteins, structure, biological function and epidemiological relationship with serotypes, combined with the immunoprotective efficacy of pilins as protein candidates for vaccines, we here systematically describe the research status and prospects of pili and provide new ideas for subsequent vaccine research and development.
Topics: Bacterial Proteins; Streptococcus pneumoniae; Fimbriae, Bacterial; Fimbriae Proteins; Vaccines; Polymers
PubMed: 37799336
DOI: 10.3389/fcimb.2023.1270848 -
Microbial Biotechnology Nov 2018The reduction of iron oxide minerals and uranium in model metal reducers in the genus Geobacter is mediated by conductive pili composed primarily of a structurally... (Review)
Review
The reduction of iron oxide minerals and uranium in model metal reducers in the genus Geobacter is mediated by conductive pili composed primarily of a structurally divergent pilin peptide that is otherwise recognized, processed and assembled in the inner membrane by a conserved Type IVa pilus apparatus. Electronic coupling among the peptides is promoted upon assembly, allowing the discharge of respiratory electrons at rates that greatly exceed the rates of cellular respiration. Harnessing the unique properties of these conductive appendages and their peptide building blocks in metal bioremediation will require understanding of how the pilins assemble to form a protein nanowire with specialized sites for metal immobilization. Also important are insights into how cells assemble the pili to make an electroactive matrix and grow on electrodes as biofilms that harvest electrical currents from the oxidation of waste organic substrates. Genetic engineering shows promise to modulate the properties of the peptide building blocks, protein nanowires and current-harvesting biofilms for various applications. This minireview discusses what is known about the pilus material properties and reactions they catalyse and how this information can be harnessed in nanotechnology, bioremediation and bioenergy applications.
Topics: Bacterial Proteins; Biofilms; Biotechnology; Electrodes; Fimbriae, Bacterial; Geobacter; Nanowires; Oxidation-Reduction
PubMed: 29806247
DOI: 10.1111/1751-7915.13280 -
Microbiology Spectrum Mar 2019Type IV pilus (T4P)-like systems have been identified in almost every major phylum of prokaryotic life. They include the type IVa pilus (T4aP), type II secretion system... (Review)
Review
Type IV pilus (T4P)-like systems have been identified in almost every major phylum of prokaryotic life. They include the type IVa pilus (T4aP), type II secretion system (T2SS), type IVb pilus (T4bP), Tad/Flp pilus, Com pilus, and archaeal flagellum (archaellum). These systems are used for adhesion, natural competence, phage adsorption, folded-protein secretion, surface sensing, swimming motility, and twitching motility. The T4aP allows for all of these functions except swimming and is therefore a good model system for understanding T4P-like systems. Recent structural analyses have revolutionized our understanding of how the T4aP machinery assembles and functions. Here we review the structure and function of the T4aP.
Topics: Fimbriae Proteins; Fimbriae, Bacterial; Flagella; Protein Transport; Type II Secretion Systems
PubMed: 30825300
DOI: 10.1128/microbiolspec.PSIB-0006-2018