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Proceedings of the National Academy of... Apr 2024Type IVa pili (T4aP) are ubiquitous cell surface filaments important for surface motility, adhesion to surfaces, DNA uptake, biofilm formation, and virulence. T4aP are...
Type IVa pili (T4aP) are ubiquitous cell surface filaments important for surface motility, adhesion to surfaces, DNA uptake, biofilm formation, and virulence. T4aP are built from thousands of copies of the major pilin subunit and tipped by a complex composed of minor pilins and in some systems also the PilY1 adhesin. While major pilins of structurally characterized T4aP have lengths of <165 residues, the major pilin PilA of is unusually large with 208 residues. All major pilins have a conserved N-terminal domain and a variable C-terminal domain, and the additional residues of PilA are due to a larger C-terminal domain. We solved the structure of the T4aP (T4aP) at a resolution of 3.0 Å using cryo-EM. The T4aP follows the structural blueprint of other T4aP with the pilus core comprised of the interacting N-terminal α1-helices, while the globular domains decorate the T4aP surface. The atomic model of PilA built into this map shows that the large C-terminal domain has more extensive intersubunit contacts than major pilins in other T4aP. As expected from these greater contacts, the bending and axial stiffness of the T4aP is significantly higher than that of other T4aP and supports T4aP-dependent motility on surfaces of different stiffnesses. Notably, T4aP variants with interrupted intersubunit interfaces had decreased bending stiffness, pilus length, and strongly reduced motility. These observations support an evolutionary scenario whereby the large major pilin enables the formation of a rigid T4aP that expands the environmental conditions in which the T4aP system functions.
Topics: Fimbriae Proteins; Myxococcus xanthus; Fimbriae, Bacterial; Protein Structure, Secondary; Virulence
PubMed: 38625941
DOI: 10.1073/pnas.2321989121 -
BioRxiv : the Preprint Server For... Apr 2024Chronic polymicrobial infections involving and are prevalent, difficult to eradicate, and associated with poor health outcomes. Therefore, understanding interactions...
Chronic polymicrobial infections involving and are prevalent, difficult to eradicate, and associated with poor health outcomes. Therefore, understanding interactions between these pathogens is important to inform improved treatment development. We previously demonstrated that is attracted to using type IV pili-mediated chemotaxis, but the impact of attraction on growth and physiology remained unknown. Using live single-cell confocal imaging to visualize microcolony structure, spatial organization, and survival of during coculture, we found that interspecies chemotaxis provides a competitive advantage by promoting invasion into and disruption of microcolonies. This behavior renders susceptible to antimicrobials. Conversely, in the absence of type IV pilus motility, cells exhibit reduced invasion of colonies. Instead, builds a cellular barrier adjacent to and secretes diffusible, bacteriostatic antimicrobials like 2-heptyl-4-hydroxyquinoline-oxide (HQNO) into the colonies. reduced invasion leads to the formation of denser and thicker colonies with significantly increased HQNO-mediated lactic acid fermentation, a physiological change that could complicate the effective treatment of infections. Finally, we show that motility modifications of spatial structure enhance competition against . Overall, these studies build on our understanding of how type IV pili-mediated interspecies chemotaxis mediates polymicrobial interactions, highlighting the importance of spatial positioning in mixed-species communities.
PubMed: 38617332
DOI: 10.1101/2024.04.03.588010 -
Nature Communications Apr 2024Phages exert profound evolutionary pressure on bacteria by interacting with receptors on the cell surface to initiate infection. While the majority of phages use...
Phages exert profound evolutionary pressure on bacteria by interacting with receptors on the cell surface to initiate infection. While the majority of phages use chromosomally encoded cell surface structures as receptors, plasmid-dependent phages exploit plasmid-encoded conjugation proteins, making their host range dependent on horizontal transfer of the plasmid. Despite their unique biology and biotechnological significance, only a small number of plasmid-dependent phages have been characterized. Here we systematically search for new plasmid-dependent phages targeting IncP and IncF plasmids using a targeted discovery platform, and find that they are common and abundant in wastewater, and largely unexplored in terms of their genetic diversity. Plasmid-dependent phages are enriched in non-canonical types of phages, and all but one of the 65 phages we isolated were non-tailed, and members of the lipid-containing tectiviruses, ssDNA filamentous phages or ssRNA phages. We show that plasmid-dependent tectiviruses exhibit profound differences in their host range which is associated with variation in the phage holin protein. Despite their relatively high abundance in wastewater, plasmid-dependent tectiviruses are missed by metaviromic analyses, underscoring the continued importance of culture-based phage discovery. Finally, we identify a tailed phage dependent on the IncF plasmid, and find related structural genes in phages that use the orthogonal type 4 pilus as a receptor, highlighting the evolutionarily promiscuous use of these distinct contractile structures by multiple groups of phages. Taken together, these results indicate plasmid-dependent phages play an under-appreciated evolutionary role in constraining horizontal gene transfer via conjugative plasmids.
Topics: Bacteriophages; Wastewater; Biological Evolution; Biotechnology; Cell Membrane
PubMed: 38609370
DOI: 10.1038/s41467-024-47416-z -
Proceedings of the Japan Academy.... 2024I. Watanabe et al. isolated approximately 30 strains of RNA phages from various parts of Japan. To isolate RNA phages, they assessed the infection specificity of male...
I. Watanabe et al. isolated approximately 30 strains of RNA phages from various parts of Japan. To isolate RNA phages, they assessed the infection specificity of male Escherichia coli and RNase sensitivity. They found that the isolated strains of RNA phages could be serologically separated into three groups. Furthermore, most of them were serologically related, and the antiphage rabbit serum prepared by one of these phages neutralized most of the other phages. The only serologically unrelated phage was the RNA phage Qβ, which was isolated at the Institute for Virus Research, Kyoto University, in 1961.
Topics: Humans; Male; Rabbits; Animals; RNA Phages; Escherichia coli; Japan
PubMed: 38599846
DOI: 10.2183/pjab.100.017 -
Canadian Journal of Veterinary Research... Apr 2024Enterotoxigenic (ETEC) is an important type of pathogenic bacteria that causes diarrhea in pigs. The objective of this study was to prepare a novel tetravalent vaccine...
Enterotoxigenic (ETEC) is an important type of pathogenic bacteria that causes diarrhea in pigs. The objective of this study was to prepare a novel tetravalent vaccine to effectively prevent piglet diarrhea caused by In order to realize the production of tetravalent inactivated vaccine, the biological characteristics, stability, preservation conditions, and safety of the recombinant strain BL21(DE3) (pXKKSL4) were studied, and the vaccine efficacy and minimum immune dose were measured. The results indicated that the biological characteristics, target protein expression, and immunogenicity of the 1st to 10th generations of the strain were stable. Therefore, the basic seed generation was preliminarily set as the 1st to 10th generations. The results of the efficacy tests showed that the immune protection rate could reach 90% with 1 minimum lethal dose (MLD) virulent strain attack in mice. The immunogenicity was stable, and the minimum immune dose was 0.1 mL per mouse. Our research showed that the genetically engineered vaccine developed in this way could prevent piglet diarrhea caused by enterotoxigenic through adhesin and enterotoxin. In order to realize industrial production of the vaccine as soon as possible, we conducted immunological tests and production process research on the constructed tetravalent inactivated vaccine. The results of this study provide scientific experimental data for the commercial production of vaccines and lay a solid foundation for their industrial production.
Topics: Animals; Swine; Mice; Enterotoxins; Enterotoxigenic Escherichia coli; Bacterial Toxins; Vaccines, Combined; Escherichia coli Infections; Escherichia coli Vaccines; Diarrhea; Escherichia coli Proteins; Vaccines, Inactivated; Antibodies, Bacterial; Rodent Diseases; Swine Diseases
PubMed: 38595949
DOI: No ID Found -
Nature Communications Apr 2024Type 1 pili are important virulence factors of uropathogenic Escherichia coli that mediate bacterial attachment to epithelial cells in the urinary tract. The pilus rod...
Type 1 pili are important virulence factors of uropathogenic Escherichia coli that mediate bacterial attachment to epithelial cells in the urinary tract. The pilus rod is comprised of thousands of copies of the main structural subunit FimA and is assembled in vivo by the assembly platform FimD. Although type 1 pilus rods can self-assemble from FimA in vitro, this reaction is slower and produces structures with lower kinetic stability against denaturants compared to in vivo-assembled rods. Our study reveals that FimD-catalysed in vitro-assembled type 1 pilus rods attain a similar stability as pilus rods assembled in vivo. Employing structural, biophysical and biochemical analyses, we show that in vitro assembly reactions lacking FimD produce pilus rods with structural defects, reducing their stability against dissociation. Overall, our results indicate that FimD is not only required for the catalysis of pilus assembly, but also to control the assembly of the most stable quaternary structure.
Topics: Fimbriae Proteins; Escherichia coli Proteins; Escherichia coli; Fimbriae, Bacterial
PubMed: 38589417
DOI: 10.1038/s41467-024-47212-9 -
MBio May 2024Among genes present in all group A streptococci (GAS), those encoding M-fibril and T-pilus proteins display the highest levels of sequence diversity, giving rise to the...
Among genes present in all group A streptococci (GAS), those encoding M-fibril and T-pilus proteins display the highest levels of sequence diversity, giving rise to the two primary serological typing schemes historically used to define strain. A new genotyping scheme for the pilin adhesin and backbone genes is developed and, when combined with typing, provides an account of the global GAS strain population. Cluster analysis based on nucleotide sequence similarity assigns most T-serotypes to discrete pilin backbone sequence clusters, yet the established T-types correspond to only half the clusters. The major pilin adhesin and backbone sequence clusters yield 98 unique combinations, defined as "pilin types." Numerous horizontal transfer events that involve pilin or genes generate extensive antigenic and functional diversity on the bacterial cell surface and lead to the emergence of new strains. Inferred pilin genotypes applied to a meta-analysis of global population-based collections of pharyngitis and impetigo isolates reveal highly significant associations between pilin genotypes and GAS infection at distinct ecological niches, consistent with a role for pilin gene products in adaptive evolution. Integration of and pilin typing into open-access online tools (pubmlst.org) ensures broad utility for end-users wanting to determine the architecture of M-fibril and T-pilus genes from genome assemblies.IMPORTANCEPrecision in defining the variant forms of infectious agents is critical to understanding their population biology and the epidemiology of associated diseases. Group A (GAS) is a global pathogen that causes a wide range of diseases and displays a highly diverse cell surface due to the antigenic heterogeneity of M-fibril and T-pilus proteins which also act as virulence factors of varied functions. genotyping is well-established and highly utilized, but there is no counterpart for pilin genes. A global GAS collection provides the basis for a comprehensive pilin typing scheme, and online tools for determining and pilin genotypes are developed. Application of these tools reveals the expansion of structural-functional diversity among GAS via horizontal gene transfer, as evidenced by unique combinations of surface protein genes. Pilin and genotype correlations with superficial throat vs skin infection provide new insights on the molecular determinants underlying key ecological and epidemiological trends.
Topics: Streptococcus pyogenes; Genetic Variation; Humans; Genotype; Recombination, Genetic; Bacterial Outer Membrane Proteins; Fimbriae Proteins; Gene Transfer, Horizontal; Antigens, Bacterial; Streptococcal Infections; Impetigo; Pharyngitis; Fimbriae, Bacterial; Carrier Proteins
PubMed: 38587426
DOI: 10.1128/mbio.00693-24 -
Research in Microbiology Apr 2024The Burkholderia cepacia complex (Bcc) is a group of increasingly multi-drug resistant opportunistic bacteria. This resistance is driven through a combination of...
The Burkholderia cepacia complex (Bcc) is a group of increasingly multi-drug resistant opportunistic bacteria. This resistance is driven through a combination of intrinsic factors and the carriage of a broad range of conjugative plasmids harbouring virulence determinants. Therefore, novel treatments are required to treat and prevent further spread of these virulence determinants. In the search for phages infective for clinical Bcc isolates, CSP1 phage, a PRD1-like phage was isolated. CSP1 phage was found to require pilus machinery commonly encoded on conjugative plasmids to facilitate infection of Gram-negative bacteria genera including Escherichia and Pseudomonas. Whole genome sequencing and characterisation of one of the clinical Burkholderia isolates revealed it to be Burkholderia contaminans. B. contaminans 5080 was found to contain a genome of over 8 Mbp encoding multiple intrinsic resistance factors, such as efflux pump systems, but more interestingly, carried three novel plasmids encoding multiple putative virulence factors for increased host fitness, including antimicrobial resistance. Even though PRD1-like phages are broad host range, their use in novel antimicrobial treatments shouldn't be dismissed, as the dissemination potential of conjugative plasmids is extensive. Continued survey of clinical bacterial strains is also key to understanding the spread of antimicrobial resistance determinants and plasmid evolution.
PubMed: 38582389
DOI: 10.1016/j.resmic.2024.104202 -
Ecotoxicology and Environmental Safety May 2024Cylindrospermopsin (CYN), a cyanobacterial toxin, has been detected in the global water environment. However, information concerning the potential environmental risk of...
Cylindrospermopsin (CYN), a cyanobacterial toxin, has been detected in the global water environment. However, information concerning the potential environmental risk of CYN is limited, since the majority of previous studies have mainly focused on the adverse health effects of CYN through contaminated drinking water. The present study reported that CYN at environmentally relevant levels (0.1-100 μg/L) can significantly enhance the conjugative transfer of RP4 plasmid in Escherichia coli genera, wherein application of 10 μg/L of CYN led to maximum fold change of ∼6.5- fold at 16 h of exposure. Meanwhile, evaluation of underlying mechanisms revealed that environmental concentration of CYN exposure could increase oxidative stress in the bacterial cells, resulting in ROS overproduction. In turn, this led to an upregulation of antioxidant enzyme-related genes to avoid ROS attack. Further, inhibition of the synthesis of glutathione (GSH) was also detected, which led to the rapid depletion of GSH in cells and thus triggered the SOS response and promoted the conjugative transfer process. Increase in cell membrane permeability, upregulation of expression of genes related to pilus generation, ATP synthesis, and RP4 gene expression were also observed. These results highlight the potential impact on the spread of antimicrobial resistance in water environments.
Topics: Cyanobacteria Toxins; Alkaloids; Plasmids; Glutathione; Escherichia coli; Bacterial Toxins; Uracil; Oxidative Stress; Reactive Oxygen Species; Conjugation, Genetic; Drug Resistance, Multiple, Bacterial
PubMed: 38581909
DOI: 10.1016/j.ecoenv.2024.116288 -
Current Opinion in Microbiology Jun 2024Bacteria utilize type IV pili (T4P) to interact with their environment, where they facilitate processes including motility, adherence, and DNA uptake. T4P require... (Review)
Review
Bacteria utilize type IV pili (T4P) to interact with their environment, where they facilitate processes including motility, adherence, and DNA uptake. T4P require multisubunit, membrane-spanning nanomachines for assembly. The tight adherence (Tad) pili are an Archaea-derived T4P subgroup whose machinery exhibits significant mechanistic and architectural differences from bacterial type IVa and IVb pili. Most Tad biosynthetic genes are encoded in a single locus that is widespread in bacteria due to facile acquisition via horizontal gene transfer. These loci experience extensive structural rearrangements, including the acquisition of novel regulatory or biosynthetic genes, which fine-tune their function. This has permitted their integration into many different bacterial lifestyles, including the Caulobacter crescentus cell cycle, Myxococcus xanthus predation, and numerous plant and mammalian pathogens and symbionts.
Topics: Fimbriae, Bacterial; Caulobacter crescentus; Bacteria; Bacterial Adhesion; Gene Transfer, Horizontal; Fimbriae Proteins; Bacterial Proteins; Myxococcus xanthus
PubMed: 38579360
DOI: 10.1016/j.mib.2024.102468