-
Biochemical Society Transactions Dec 2016Type IV pili are hair-like bacterial surface appendages that play a role in diverse processes such as cellular adhesion, colonization, twitching motility, biofilm... (Review)
Review
Type IV pili are hair-like bacterial surface appendages that play a role in diverse processes such as cellular adhesion, colonization, twitching motility, biofilm formation, and horizontal gene transfer. These extracellular fibers are composed exclusively or primarily of many copies of one or more pilin proteins, tightly packed in a helix so that the highly hydrophobic amino-terminus of the pilin is buried in the pilus core. Type IV pili have been characterized extensively in Gram-negative bacteria, and recent advances in high-throughput genomic sequencing have revealed that they are also widespread in Gram-positive bacteria. Here, we review the current state of knowledge of type IV pilus systems in Gram-positive bacterial species and discuss them in the broader context of eubacterial type IV pili.
Topics: Bacterial Adhesion; Fimbriae Proteins; Fimbriae, Bacterial; Gram-Positive Bacteria; Models, Molecular; Movement; Mutation; Protein Domains; Species Specificity
PubMed: 27913675
DOI: 10.1042/BST20160221 -
Microbial Pathogenesis Mar 2018Group B Streptococcus (GBS) is a versatile organism which uses multiple virulence factors which bind to the surface of epithelial cells. Pili are one of virulence...
Group B Streptococcus (GBS) is a versatile organism which uses multiple virulence factors which bind to the surface of epithelial cells. Pili are one of virulence factors detected in recent years. A total of 90 isolates were collected from invasive and non-invasive isolates among adults throughout 2014-2015. Isolates were serotyped at molecular level based on capsular polysaccharide (cps) serotyping and analyzed for pilus island profiles, scpB gene, and hvgA gene presence. Isolates were subjected to antimicrobial susceptibility towards penicillin, tetracycline, erythromycin, clindamycin, moxifloxacin, levofloxacin, and vancomycin by disk diffusion method and MICs for erythromycin and clindamycin were determined by broth dilution methods. Overall, 4 serotypes were identified, serotype III (68.88%), V (20%), II (10%) and Ib (1.11%) and hvgA gene was detected in 7.7% (n = 7) of the isolates; all were serotype III/ST 17. All isolates were susceptible to penicillin and vancomycin, except one isolate which showed intermediate resistance to penicillin and other complete resistance to vancomycin. Isolates were resistant to tetracycline (98%), erythromycin (25%), clindamycin (22%), moxifloxacin (8%), and levofloxacin (6%). The scpB gene was detected in all isolates, while isolates harbored at least one PI, of which the PI-1+PI-2a was the most frequent combination observed. Our data show the presence of the relation between serotype or pilus genes among clinical isolates of Streptococcus agalactiae. These data are principal to help in designing prevention and treatment strategies for GBS infections in the region.
Topics: Adolescent; Adult; Disk Diffusion Antimicrobial Tests; Drug Resistance, Bacterial; Female; Fimbriae, Bacterial; Genes, Bacterial; Genomic Islands; Humans; Membrane Glycoproteins; Polymerase Chain Reaction; Pregnancy; Serogroup; Streptococcal Infections; Streptococcus agalactiae; Young Adult
PubMed: 29371153
DOI: 10.1016/j.micpath.2018.01.035 -
Microbiology Spectrum Oct 2015Bacteria assemble a wide range of adhesive proteins, termed adhesins, to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are... (Review)
Review
Bacteria assemble a wide range of adhesive proteins, termed adhesins, to mediate binding to receptors and colonization of surfaces. For pathogenic bacteria, adhesins are critical for early stages of infection, allowing the bacteria to initiate contact with host cells, colonize different tissues, and establish a foothold within the host. The adhesins expressed by a pathogen are also critical for bacterial-bacterial interactions and the formation of bacterial communities, including biofilms. The ability to adhere to host tissues is particularly important for bacteria that colonize sites such as the urinary tract, where the flow of urine functions to maintain sterility by washing away non-adherent pathogens. Adhesins vary from monomeric proteins that are directly anchored to the bacterial surface to polymeric, hair-like fibers that extend out from the cell surface. These latter fibers are termed pili or fimbriae, and were among the first identified virulence factors of uropathogenic Escherichia coli. Studies since then have identified a range of both pilus and non-pilus adhesins that contribute to bacterial colonization of the urinary tract, and have revealed molecular details of the structures, assembly pathways, and functions of these adhesive organelles. In this review, we describe the different types of adhesins expressed by both Gram-negative and Gram-positive uropathogens, what is known about their structures, how they are assembled on the bacterial surface, and the functions of specific adhesins in the pathogenesis of urinary tract infections.
Topics: Adhesins, Bacterial; Bacterial Adhesion; Fimbriae, Bacterial; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Urinary Tract
PubMed: 26542038
DOI: 10.1128/microbiolspec.UTI-0018-2013 -
Archives of Microbiology Aug 2015Many pathogenic bacteria express filamentous appendages, termed pili, on their surface. These organelles function in several important bacterial processes, including... (Review)
Review
Many pathogenic bacteria express filamentous appendages, termed pili, on their surface. These organelles function in several important bacterial processes, including mediating bacterial interaction with, and colonization of the host, signalling events, locomotion, DNA uptake, electric conductance, and biofilm formation. In the last decade, it has been established that the tuberculosis-causing bacterium, Mycobacterium tuberculosis, produces two pili types: curli and type IV pili. In this paper, we review studies on M. tuberculosis pili, highlighting their structure and biological significance to M. tuberculosis pathogenesis, and discuss their potential as targets for therapeutic intervention and diagnostic test development.
Topics: Bacterial Adhesion; Fimbriae, Bacterial; Mycobacterium tuberculosis; Tuberculosis
PubMed: 25975850
DOI: 10.1007/s00203-015-1117-0 -
Viruses Jan 2021The bacterial and archaeal cell surface is decorated with filamentous surface structures that are used for different functions, such as motility, DNA exchange and... (Review)
Review
The bacterial and archaeal cell surface is decorated with filamentous surface structures that are used for different functions, such as motility, DNA exchange and biofilm formation. Viruses hijack these structures and use them to ride to the cell surface for successful entry. In this review, we describe currently known mechanisms for viral attachment, translocation, and entry via filamentous surface structures. We describe the different mechanisms used to exploit various surface structures bacterial and archaeal viruses. This overview highlights the importance of filamentous structures at the cell surface for entry of prokaryotic viruses.
Topics: Archaea; Archaeal Viruses; Bacteria; Bacteriophages; Cytoskeleton; Fimbriae Proteins; Fimbriae, Bacterial; Flagella
PubMed: 33499367
DOI: 10.3390/v13020164 -
Biofouling Sep 2020The initial colonization of the host organism by commensal, probiotic, and pathogenic strains is an important step in the development of infections and biofilms.... (Review)
Review
The initial colonization of the host organism by commensal, probiotic, and pathogenic strains is an important step in the development of infections and biofilms. Sensing and colonization of host cell surfaces are governed by flagellar and fimbriae/pili appendages, respectively. Biofilm formation confers great advantages on pathogenic cells such as protection against the host immune system, antimicrobial agents, and several environmental stress factors. The transition from planktonic to sessile physiological states involves several signaling cascades and factors responsible for the regulation of flagellar motility in cells. These regulatory factors have thus become important targets to control pathogenicity. Hence, attenuation of flagellar motility is considered a potential therapy against pathogenic . The present review describes signaling pathways and proteins involved in direct or indirect regulation of flagellar motility. Furthermore, application strategies for antimotility natural or synthetic compounds are discussed also.
Topics: Biofilms; Escherichia coli; Escherichia coli Proteins; Fimbriae, Bacterial; Gene Expression Regulation, Bacterial
PubMed: 33028083
DOI: 10.1080/08927014.2020.1826939 -
Journal of Bacteriology Nov 2022In addition to providing a typing mechanism for group A Streptococcus (GAS) isolates (T typing), cell surface pilus production impacts GAS virulence characteristics,...
In addition to providing a typing mechanism for group A Streptococcus (GAS) isolates (T typing), cell surface pilus production impacts GAS virulence characteristics, including adherence and immune evasion. The pilus biosynthesis genes are located in the fibronectin- and collagen-binding T-antigen (FCT) region of the genome, and nine different FCT types, encoding more than 20 different T types, have been described. GAS isolates are not uniform in their degree or pattern of pilus expression, as highlighted by pilus production being thermoregulated in isolates that harbor the FCT-type FCT-3 (e.g., M-types M3 and M49) but not in isolates that harbor FCT-2 (e.g., M-type M1). Here, we investigated the molecular basis underlying our previous finding that M3 GAS isolates produce pili in lower abundance than M1 or M49 isolates do. We discovered that, at least in part, the low pilus expression observed for M3 isolates is a consequence of the repression of pilus gene expression by the CovR/CovS two-component regulatory system and of an M3-specific mutation in the gene, encoding a positive regulator of pilus gene expression. We also discovered that the orthologous transcriptional regulators RofA and Nra, whose encoding genes are located within FCT-2 and FCT-3, respectively, are not functionally identical. Finally, we sequenced the genome of an M3 isolate that had naturally undergone recombinational replacement of the FCT region, changing the FCT and T types of this strain from FCT-3/T3 to FCT-2/T1. Our study furthers the understanding of strain- and type-specific variation in virulence factor production by an important human pathogen. Our ability to characterize how a pathogen infects and causes disease, and consequently our ability to devise approaches to prevent or attenuate such infections, is inhibited by the finding that isolates of a given pathogen often show phenotypic variability, for example, in their ability to adhere to host cells through modulation of cell surface adhesins. Such variability is observed between isolates of group A Streptococcus (GAS), and this study investigates the molecular basis for why some GAS isolates produce pili, cell wall-anchored adhesins, in lower abundance than other isolates do. Given that pili are being considered as potential antigens in formulations of future GAS vaccines, this study may inform vaccine design.
Topics: Humans; Streptococcal Infections; Bacterial Proteins; Streptococcus pyogenes; Fimbriae, Bacterial; Adhesins, Bacterial; Gene Expression Regulation, Bacterial
PubMed: 36286511
DOI: 10.1128/jb.00270-22 -
International Journal of Molecular... Nov 2021The endospores (spores) of many sensu lato species are decorated with multiple hair/pilus-like appendages. Although they have been observed for more than 50 years, all... (Review)
Review
The endospores (spores) of many sensu lato species are decorated with multiple hair/pilus-like appendages. Although they have been observed for more than 50 years, all efforts to characterize these fibers in detail have failed until now, largely due to their extraordinary resilience to proteolytic digestion and chemical solubilization. A recent structural analysis of endospore appendages (Enas) using cryo-electron microscopy has revealed the structure of two distinct fiber morphologies: the longer and more abundant "Staggered-type" (S-Ena) and the shorter "Ladder-like" type (L-Ena), which further enabled the identification of the genes encoding the S-Ena. Ena homologs are widely and uniquely distributed among sensu lato species, suggesting that appendages play important functional roles in these species. The discovery of genes is expected to facilitate functional studies involving Ena-depleted mutant spores to explore the role of Enas in the interaction between spores and their environment. Given the importance of spores for the food industry and in medicine, there is a need for a better understanding of their biological functions and physicochemical properties. In this review, we discuss the current understanding of the Ena structure and the potential roles these remarkable fibers may play in the adhesion of spores to biotic and abiotic surfaces, aggregation, and biofilm formation.
Topics: Bacillus cereus; Bacterial Proteins; Binding Sites; Biofilms; Cryoelectron Microscopy; Fimbriae, Bacterial; Gene Expression Regulation, Bacterial; Models, Molecular; Protein Binding; Protein Conformation, beta-Strand; Protein Interaction Domains and Motifs; Spores, Bacterial
PubMed: 34830248
DOI: 10.3390/ijms222212367 -
Trends in Microbiology Jun 2015Understanding the fundamental forces involved in the adhesion of microbial cells is important not only in microbiology, to elucidate cellular functions (such as... (Review)
Review
Understanding the fundamental forces involved in the adhesion of microbial cells is important not only in microbiology, to elucidate cellular functions (such as ligand-binding or biofilm formation), but also in medicine (biofilm infections) and biotechnology (cell aggregation). Rapid progress in atomic force microscopy (AFM) techniques has made it possible to measure the forces driving cell-cell and cell-substrate interactions on a single cell basis. A living cell is attached to the AFM probe, thereby enabling researchers to measure the interaction forces between the cell and a target surface. Recent advances in our understanding of the forces driving cell adhesion and biofilm formation are discussed, with a focus on pathogens. These studies provide compelling evidence that, upon contact with a surface, cell adhesion components display a variety of mechanical responses that are important for cell adhesion.
Topics: Bacterial Adhesion; Biofilms; Fimbriae, Bacterial; Microscopy, Atomic Force
PubMed: 25684261
DOI: 10.1016/j.tim.2015.01.011 -
Acta Crystallographica. Section F,... Aug 2021Adhesion to host surfaces for bacterial survival and colonization involves a variety of molecular mechanisms. Ligilactobacillus ruminis, a strict anaerobe and gut...
Adhesion to host surfaces for bacterial survival and colonization involves a variety of molecular mechanisms. Ligilactobacillus ruminis, a strict anaerobe and gut autochthonous (indigenous) commensal, relies on sortase-dependent pili (LrpCBA) for adherence to the intestinal inner walls, thereby withstanding luminal content flow. Here, the LrpCBA pilus is a promiscuous binder to gut collagen, fibronectin and epithelial cells. Structurally, the LrpCBA pilus displays a representative hetero-oligomeric arrangement and consists of three types of pilin subunit, each with its own location and function, i.e. tip LrpC for adhesion, basal LrpB for anchoring and backbone LrpA for length. To provide further structural insights into the assembly, anchoring and functional mechanisms of sortase-dependent pili, each of the L. ruminis pilus proteins was produced recombinantly for crystallization and X-ray diffraction analysis. Crystals of LrpC, LrpB, LrpA and truncated LrpA generated by limited proteolysis were obtained and diffracted to resolutions of 3.0, 1.5, 2.2 and 1.4 Å, respectively. Anomalous data were also collected from crystals of selenomethionine-substituted LrpC and an iodide derivative of truncated LrpA. Successful strategies for protein production, crystallization and derivatization are reported.
Topics: Amino Acid Sequence; Crystallization; Crystallography, X-Ray; Fimbriae, Bacterial; Gastrointestinal Microbiome; Lactobacillus; X-Ray Diffraction
PubMed: 34341189
DOI: 10.1107/S2053230X21007263