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Halte M, Andrianova EP, Goosmann C, Chevance FFV, Hughes KT, Zhulin IB, Erhardt M. FlhE functions as a chaperone to prevent formation of periplasmic flagella in Gram-negative bacteria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.03.11.584431. [PMID: 38558991 PMCID: PMC10979839 DOI: 10.1101/2024.03.11.584431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
The bacterial flagellum is an organelle utilized by many Gram-negative bacteria to facilitate motility. The flagellum is composed of a several µm long, extracellular filament that is connected to a cytoplasmic rotor-stator complex via a periplasmic rod. Composed of ∼20 structural proteins, ranging from a few subunits to several thousand building blocks, the flagellum is a paradigm of a complex macromolecular structure that utilizes a highly regulated assembly process. This process is governed by multiple checkpoints that ensure an ordered gene expression pattern coupled to the assembly of the various flagellar building blocks in order to produce a functional flagellum. Using epifluorescence, super-resolution STED and transmission electron microscopy, we discovered that in Salmonella , the absence of one periplasmic protein, FlhE, prevents proper flagellar morphogenesis and results in the formation of periplasmic flagella. The periplasmic flagella disrupt cell wall synthesis, leading to a loss of the standard cell morphology resulting in cell lysis. We propose a model where FlhE functions as a periplasmic chaperone to control assembly of the periplasmic rod to prevent formation of periplasmic flagella. Our results highlight that bacteria evolved sophisticated regulatory mechanisms to control proper flagellar assembly and minor deviations from this highly regulated process can cause dramatic physiological consequences.
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Fanelli F, Montemurro M, Chieffi D, Cho GS, Low HZ, Hille F, Franz CMAP, Fusco V. Motility in Periweissella Species: Genomic and Phenotypic Characterization and Update on Motility in Lactobacillaceae. Microorganisms 2023; 11:2923. [PMID: 38138067 PMCID: PMC10745875 DOI: 10.3390/microorganisms11122923] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 11/24/2023] [Accepted: 11/28/2023] [Indexed: 12/24/2023] Open
Abstract
The genus Weissella and the recently described genus Periweissella, to which some previously named Weissella species have been reclassified as a result of a taxogenomic assessment, includes lactic acid bacteria species with high biotechnological and probiotic potential. Only one species, namely, Periweissella (P.) beninensis, whose type strain has been shown to possess probiotic features, has so far been described to be motile. However, the availability of numerous genome sequences of Weissella and Periweissella species prompted the possibility to screen for the presence of the genetic determinants encoding motility in Weissella and Periweissellas spp. other than P. beninensis. Herein, we performed a comprehensive genomic analysis to identify motility-related proteins in all Weissella and Periweissella species described so far, and extended the analysis to the recently sequenced Lactobacillaceae spp. Furthermore, we performed motility assays and transmission electron microscopy (TEM) on Periweissella type strains to confirm the genomic prediction. The homology-based analysis revealed genes coding for motility proteins only in the type strains of P. beninensis, P. fabalis, P. fabaria and P. ghanensis genomes. However, only the P. beninensis type strain was positive in the motility assay and displayed run-and-tumble behavior. Many peritrichous and long flagella on bacterial cells were visualized via TEM, as well. As for the Lactobacillaceae, in addition to the species previously described to harbor motility proteins, the genetic determinants of motility were also found in the genomes of the type strains of Lactobacillus rogosae and Ligilactobacillus salitolerans. This study, which is one of the first to analyze the genomes of Weissella, Periweissella and the recently sequenced Lactobacillaceae spp. for the presence of genes coding for motility proteins and which assesses the associated motility phenotypes, provides novel results that expand knowledge on these genera and are useful in the further characterization of lactic acid bacteria.
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Affiliation(s)
- Francesca Fanelli
- National Research Council of Italy, Institute of Sciences of Food Production (CNR-ISPA), 70126 Bari, Italy; (F.F.); (M.M.); (D.C.)
| | - Marco Montemurro
- National Research Council of Italy, Institute of Sciences of Food Production (CNR-ISPA), 70126 Bari, Italy; (F.F.); (M.M.); (D.C.)
| | - Daniele Chieffi
- National Research Council of Italy, Institute of Sciences of Food Production (CNR-ISPA), 70126 Bari, Italy; (F.F.); (M.M.); (D.C.)
| | - Gyu-Sung Cho
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103 Kiel, Germany; (G.-S.C.); (H.-Z.L.); (F.H.)
| | - Hui-Zhi Low
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103 Kiel, Germany; (G.-S.C.); (H.-Z.L.); (F.H.)
| | - Frank Hille
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103 Kiel, Germany; (G.-S.C.); (H.-Z.L.); (F.H.)
| | - Charles M. A. P. Franz
- Department of Microbiology and Biotechnology, Max Rubner-Institut, 24103 Kiel, Germany; (G.-S.C.); (H.-Z.L.); (F.H.)
| | - Vincenzina Fusco
- National Research Council of Italy, Institute of Sciences of Food Production (CNR-ISPA), 70126 Bari, Italy; (F.F.); (M.M.); (D.C.)
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3
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Kasthuri T, Barath S, Nandhakumar M, Karutha Pandian S. Proteomic profiling spotlights the molecular targets and the impact of the natural antivirulent umbelliferone on stress response, virulence factors, and the quorum sensing network of Pseudomonas aeruginosa. Front Cell Infect Microbiol 2022; 12:998540. [PMID: 36530435 PMCID: PMC9748083 DOI: 10.3389/fcimb.2022.998540] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/18/2022] [Indexed: 12/05/2022] Open
Abstract
Pseudomonas aeruginosa easily adapts to newer environments and acquires several genome flexibilities to overcome the effect of antibiotics during therapeutics, especially in cystic fibrosis patients. During adaptation to the host system, the bacteria employ various tactics including virulence factor production and biofilm formation to escape from the host immune system and resist antibiotics. Hence, identifying alternative strategies to combat recalcitrant pathogens is imperative for the successful elimination of drug-resistant microbes. In this context, this study portrays the anti-virulence efficacy of umbelliferone (UMB) against P. aeruginosa. UMB (7-hydroxy coumarin) is pervasively found among the plant family of Umbelliferae and Asteraceae. The UMB impeded biofilm formation in the P. aeruginosa reference strain and clinical isolates on polystyrene and glass surfaces at the concentration of 125 µg/ml. Global proteomic analysis of UMB-treated cells revealed the downregulation of major virulence-associated proteins such as RhlR, LasA, AlgL, FliD, Tpx, HtpG, KatA, FusA1, Tsf, PhzM, PhzB2, CarB, DctP, MtnA, and MscL. A functional interaction study, gene ontology, and KEGG pathway analysis revealed that UMB could modulate the global regulators, enzymes, co-factors, and transcription factors related to quorum sensing (QS), stress tolerance, siderophore production, motility, and microcolony formation. In vitro biochemical assays further affirmed the anti-virulence efficacy of UMB by reducing pyocyanin, protease, elastase, and catalase production in various strains of P. aeruginosa. Besides the antibiofilm activity, UMB-treated cells exhibited enhanced antibiotic susceptibility to various antibiotics including amikacin, kanamycin, tobramycin, ciprofloxacin, and cefotaxime. Furthermore, in vitro cytotoxicity analysis revealed the biocompatibility of UMB, and the IC50 value was determined to be 249.85 µg/ml on the HepG2 cell line. Altogether, the study substantiates the anti-virulence efficacy of UMB against P. aeruginosa, and the proteomic analysis reveals the differential expression of the regulators related to QS, stress response, and motility factors.
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Li H, Xie R, Xu X, Liao X, Guo J, Fang Y, Fang Z, Huang J. Static Magnetic Field Inhibits Growth of Escherichia coli Colonies via Restriction of Carbon Source Utilization. Cells 2022; 11:cells11050827. [PMID: 35269449 PMCID: PMC8909705 DOI: 10.3390/cells11050827] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 02/21/2022] [Accepted: 02/21/2022] [Indexed: 02/01/2023] Open
Abstract
Magnetobiological effects on growth and virulence have been widely reported in Escherichia coli (E. coli). However, published results are quite varied and sometimes conflicting because the underlying mechanism remains unknown. Here, we reported that the application of 250 mT static magnetic field (SMF) significantly reduces the diameter of E. coli colony-forming units (CFUs) but has no impact on the number of CFUs. Transcriptomic analysis revealed that the inhibitory effect of SMF is attributed to differentially expressed genes (DEGs) primarily involved in carbon source utilization. Consistently, the addition of glycolate or glyoxylate to the culture media successfully restores the bacterial phenotype in SMF, and knockout mutants lacking glycolate oxidase are no longer sensitive to SMF. These results suggest that SMF treatment results in a decrease in glycolate oxidase activity. In addition, metabolomic assay showed that long-chain fatty acids (LCFA) accumulate while phosphatidylglycerol and middle-chain fatty acids decrease in the SMF-treated bacteria, suggesting that SMF inhibits LCFA degradation. Based on the published evidence together with ours derived from this study, we propose a model showing that free radicals generated by LCFA degradation are the primary target of SMF action, which triggers the bacterial oxidative stress response and ultimately leads to growth inhibition.
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Affiliation(s)
- Haodong Li
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; (H.L.); (R.X.); (X.X.); (X.L.); (J.G.)
| | - Runnan Xie
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; (H.L.); (R.X.); (X.X.); (X.L.); (J.G.)
| | - Xiang Xu
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; (H.L.); (R.X.); (X.X.); (X.L.); (J.G.)
| | - Xingru Liao
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; (H.L.); (R.X.); (X.X.); (X.L.); (J.G.)
| | - Jiaxin Guo
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; (H.L.); (R.X.); (X.X.); (X.L.); (J.G.)
| | - Yanwen Fang
- Heye Health Industrial Research Institute, Zhejiang Heye Health Technology, Anji, Huzhou 313300, China; (Y.F.); (Z.F.)
| | - Zhicai Fang
- Heye Health Industrial Research Institute, Zhejiang Heye Health Technology, Anji, Huzhou 313300, China; (Y.F.); (Z.F.)
| | - Jirong Huang
- Shanghai Key Laboratory of Plant Molecular Sciences, College of Life Sciences, Shanghai Normal University, Shanghai 200234, China; (H.L.); (R.X.); (X.X.); (X.L.); (J.G.)
- Correspondence:
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5
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Minamino T, Morimoto YV, Kinoshita M, Namba K. Multiple Roles of Flagellar Export Chaperones for Efficient and Robust Flagellar Filament Formation in Salmonella. Front Microbiol 2021; 12:756044. [PMID: 34691007 PMCID: PMC8527033 DOI: 10.3389/fmicb.2021.756044] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 09/08/2021] [Indexed: 11/30/2022] Open
Abstract
FlgN, FliS, and FliT are flagellar export chaperones specific for FlgK/FlgL, FliC, and FliD, respectively, which are essential component proteins for filament formation. These chaperones facilitate the docking of their cognate substrates to a transmembrane export gate protein, FlhA, to facilitate their subsequent unfolding and export by the flagellar type III secretion system (fT3SS). Dynamic interactions of the chaperones with FlhA are thought to determine the substrate export order. To clarify the role of flagellar chaperones in filament assembly, we constructed cells lacking FlgN, FliS, and/or FliT. Removal of either FlgN, FliS, or FliT resulted in leakage of a large amount of unassembled FliC monomers into the culture media, indicating that these chaperones contribute to robust and efficient filament formation. The ∆flgN ∆fliS ∆fliT (∆NST) cells produced short filaments similarly to the ∆fliS mutant. Suppressor mutations of the ∆NST cells, which lengthened the filament, were all found in FliC and destabilized the folded structure of FliC monomer. Deletion of FliS inhibited FliC export and filament elongation only after FliC synthesis was complete. We propose that FliS is not involved in the transport of FliC upon onset of filament formation, but FliS-assisted unfolding of FliC by the fT3SS becomes essential for its rapid and efficient export to form a long filament when FliC becomes fully expressed in the cytoplasm.
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Affiliation(s)
- Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Yusuke V Morimoto
- Department of Physics and Information Technology, Faculty of Computer Science and Systems Engineering, Kyushu Institute of Technology, Iizuka, Japan.,Japan Science and Technology Agency, PRESTO, Kawaguchi, Japan
| | - Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, Suita, Japan.,RIKEN SPring-8 Center and Center for Biosystems Dynamics Research, Suita, Japan.,JEOL YOKOGUSHI Research Alliance Laboratories, Osaka University, Suita, Japan
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6
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Bacterial Flagellar Filament: A Supramolecular Multifunctional Nanostructure. Int J Mol Sci 2021; 22:ijms22147521. [PMID: 34299141 PMCID: PMC8306008 DOI: 10.3390/ijms22147521] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 07/06/2021] [Accepted: 07/10/2021] [Indexed: 02/07/2023] Open
Abstract
The bacterial flagellum is a complex and dynamic nanomachine that propels bacteria through liquids. It consists of a basal body, a hook, and a long filament. The flagellar filament is composed of thousands of copies of the protein flagellin (FliC) arranged helically and ending with a filament cap composed of an oligomer of the protein FliD. The overall structure of the filament core is preserved across bacterial species, while the outer domains exhibit high variability, and in some cases are even completely absent. Flagellar assembly is a complex and energetically costly process triggered by environmental stimuli and, accordingly, highly regulated on transcriptional, translational and post-translational levels. Apart from its role in locomotion, the filament is critically important in several other aspects of bacterial survival, reproduction and pathogenicity, such as adhesion to surfaces, secretion of virulence factors and formation of biofilms. Additionally, due to its ability to provoke potent immune responses, flagellins have a role as adjuvants in vaccine development. In this review, we summarize the latest knowledge on the structure of flagellins, capping proteins and filaments, as well as their regulation and role during the colonization and infection of the host.
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Abstract
Regulation of flagellum biosynthesis is a hierarchical process that is tightly controlled to allow for efficient tuning of flagellar expression. Flagellum-mediated motility directs Salmonella enterica serovar Typhimurium toward the epithelial surface to enhance gut colonization, but flagella are potent activators of innate immune signaling, so fine-tuning flagellar expression is necessary for immune avoidance. In this work, we evaluate the role of the LysR transcriptional regulator YeiE in regulating flagellum-mediated motility. We show that yeiE is necessary and sufficient for swimming motility. A ΔyeiE mutant is defective for gut colonization in both the calf ligated ileal loop model and the murine colitis model due to its lack of motility. Expression of flagellar class 2 and 3 but not class 1 genes is reduced in the ΔyeiE mutant. We linked the motility dysregulation of the ΔyeiE mutant to repression of the anti-FlhD4C2 factor STM1697. Together, our results indicate that YeiE promotes virulence by enhancing cell motility, thereby providing a new regulatory control point for flagellar expression in Salmonella Typhimurium.
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8
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Burtchett T, Love C, Sarkar R, Tripp BC. A structure-function study of C-terminal residues predicted to line the export channel in Salmonella Flagellin. Biochim Biophys Acta Gen Subj 2020; 1865:129748. [PMID: 32980501 DOI: 10.1016/j.bbagen.2020.129748] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 09/16/2020] [Accepted: 09/18/2020] [Indexed: 10/23/2022]
Abstract
BACKGROUND Structural studies of a Salmonella Typhimurium flagellin protein indicated that four polar or charged C-terminal amino acid residues line the inner channel of the flagellum. The hydrophilic character of these putative channel-lining residues was predicted to be essential to facilitate the transport of unfolded flagellin monomers during flagellar assembly. The structure-function relationship of these putative channel-lining residues was investigated by site-directed mutagenesis to examine effects of side chain polarity and size on flagella assembly and function. METHODS Channel-lining residue variants were generated using site-directed mutagenesis to substitute alanine and other residues to examine the effects of altered side-chain polarity on export and assembly. The export, in vivo motility function, and flagellar structure of variants was characterized by agar motility, video microscopy, immunofluorescence, and SDS-PAGE. RESULTS Alanine substitution yielded decreased motility and flagellar assembly for three of the four residues. However, alanine substitution of residue Arg 494 did not alter export, although substitution with negatively charged glutamate decreased motility and flagellar filament length. Furthermore, many of the C-terminal mutations affected flagellar filament morphology and stability, often resulting in more tightly coiled and/or more brittle flagella than the wild type. CONCLUSIONS The four channel-lining C-terminal residues may facilitate monomer protein transport but also have structural roles in determining the stability and morphology of the flagellum. GENERAL SIGNIFICANCE These results provide further insight into the complex process of bacterial flagellin export and flagellar assembly and provide evidence of previously unknown structural functions for the four putative channel-lining residues.
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Affiliation(s)
- Troy Burtchett
- Western Michigan University, Department of Biological Sciences, 1903 W. Michigan Avenue, Kalamazoo, MI 49008, USA
| | - Chloe Love
- Kalamazoo College, Department of Biology, 1200 Academy St., Kalamazoo, MI 49006, USA
| | - Reshma Sarkar
- Western Michigan University, Department of Biological Sciences, 1903 W. Michigan Avenue, Kalamazoo, MI 49008, USA
| | - Brian C Tripp
- Western Michigan University, Department of Biological Sciences, 1903 W. Michigan Avenue, Kalamazoo, MI 49008, USA.
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9
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Lam WWL, Sun K, Zhang H, Au SWN. Crystal Structure of Flagellar Export Chaperone FliS in Complex With Flagellin and HP1076 of Helicobacter pylori. Front Microbiol 2020; 11:787. [PMID: 32508757 PMCID: PMC7248283 DOI: 10.3389/fmicb.2020.00787] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Accepted: 04/02/2020] [Indexed: 12/13/2022] Open
Abstract
Functional flagella formation is a widespread virulence factor that plays a critical role in survival and host colonization. Flagellar synthesis is a complex and highly coordinated process. The assembly of the axial structure beyond the cell membrane is mediated by export chaperone proteins that transport their cognate substrates to the export gate complex. The export chaperone FliS interacts with flagellin, the basic component used to construct the filament. Unlike enterobacteria, the gastric pathogen Helicobacter pylori produces two different flagellins, FlaA and FlaB, which exhibit distinct spatial localization patterns in the filament. Previously, we demonstrated a molecular interaction between FliS and an uncharacterized protein, HP1076, in H. pylori. Here, we present the crystal structure of FliS in complex with both the C-terminal D0 domain of FlaB and HP1076. Although this ternary complex reveals that FliS interacts with flagellin using a conserved binding mode demonstrated previously in Aquifex aeolicus, Bacillus subtilis, and Salmonella enterica serovar Typhimurium, the helical conformation of FlaB in this complex was different. Moreover, HP1076 and the D1 domain of flagellin share structural similarity and interact with the same binding interface on FliS. This observation was further validated through competitive pull-down assays and kinetic binding analyses. Interestingly, we did not observe any detrimental flagellation or motility phenotypes in an hp1076-null strain. Our localization studies suggest that HP1076 is a membrane-associated protein with a cellular localization independent of FliS. As HP1076 is uniquely expressed in H. pylori and related species, we propose that this protein may contribute to the divergence of the flagellar system, although its relationship with FliS remains incompletely elucidated.
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Affiliation(s)
- Wendy Wai-Ling Lam
- Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Kailei Sun
- Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Huawei Zhang
- Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
| | - Shannon Wing-Ngor Au
- Center for Protein Science and Crystallography, School of Life Sciences, Faculty of Science, Chinese University of Hong Kong, Shatin, Hong Kong
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Zhang K, Qin Z, Chang Y, Liu J, Malkowski MG, Shipa S, Li L, Qiu W, Zhang JR, Li C. Analysis of a flagellar filament cap mutant reveals that HtrA serine protease degrades unfolded flagellin protein in the periplasm of Borrelia burgdorferi. Mol Microbiol 2019; 111:1652-1670. [PMID: 30883947 DOI: 10.1111/mmi.14243] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2019] [Indexed: 12/16/2022]
Abstract
Unlike external flagellated bacteria, spirochetes have periplasmic flagella (PF). Very little is known about how PF are assembled within the periplasm of spirochaetal cells. Herein, we report that FliD (BB0149), a flagellar cap protein (also named hook-associated protein 2), controls flagellin stability and flagellar filament assembly in the Lyme disease spirochete Borrelia burgdorferi. Deletion of fliD leads to non-motile mutant cells that are unable to assemble flagellar filaments and pentagon-shaped caps (10 nm in diameter, 12 nm in length). Interestingly, FlaB, a major flagellin protein of B. burgdorferi, is degraded in the fliD mutant but not in other flagella-deficient mutants (i.e., in the hook, rod, or MS-ring). Biochemical and genetic studies reveal that HtrA, a serine protease of B. burgdorferi, controls FlaB turnover. Specifically, HtrA degrades unfolded but not polymerized FlaB, and deletion of htrA increases the level of FlaB in the fliD mutant. Collectively, we propose that the flagellar cap protein FliD promotes flagellin polymerization and filament growth in the periplasm. Deletion of fliD abolishes this process, which leads to leakage of unfolded FlaB proteins into the periplasm where they are degraded by HtrA, a protease that prevents accumulation of toxic products in the periplasm.
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Affiliation(s)
- Kai Zhang
- Department of Oral and Craniofacial Molecular Biology, Philips Research Institute, Virginia Commonwealth University, Richmond, VI, 23298, USA
| | - Zhuan Qin
- Department of Microbial Pathogenesis & Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, 06516, USA
| | - Yunjie Chang
- Department of Microbial Pathogenesis & Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, 06516, USA
| | - Jun Liu
- Department of Microbial Pathogenesis & Microbial Sciences Institute, Yale University School of Medicine, New Haven, CT, 06516, USA
| | - Michael G Malkowski
- Department of Structural Biology, Jacobs School of Medicine and Biomedical Sciences, University of Buffalo, Buffalo, NY, 14203, USA
| | - Saimtun Shipa
- Department of Biological Sciences, City University of New York, New York, NY, 10021, USA
| | - Li Li
- Department of Biological Sciences, City University of New York, New York, NY, 10021, USA
| | - Weigang Qiu
- Department of Biological Sciences, City University of New York, New York, NY, 10021, USA
| | - Jing-Ren Zhang
- Center for Infectious Disease Research, School of Medicine, Tsinghua University, Beijing, 100084, China
| | - Chunhao Li
- Department of Oral and Craniofacial Molecular Biology, Philips Research Institute, Virginia Commonwealth University, Richmond, VI, 23298, USA
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11
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Moon KH, Zhao X, Xu H, Liu J, Motaleb MA. A tetratricopeptide repeat domain protein has profound effects on assembly of periplasmic flagella, morphology and motility of the lyme disease spirochete Borrelia burgdorferi. Mol Microbiol 2018; 110:634-647. [PMID: 30303576 DOI: 10.1111/mmi.14121] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/05/2018] [Indexed: 02/07/2023]
Abstract
Spirochetes possess a unique periplasmic flagellar motor component called the collar. However, little is known about the composition or function of the flagellar collar proteins. To identify a collar protein, we have inactivated almost all genes annotated as motility-related in the Borrelia burgdorferi genome and identified only FlbB, which comprises the base of the collar. Since the major components of the collar complex remained unidentified, we took advantage of a protein-protein interaction map developed in another spirochete, Treponema pallidum to identify proteins of unknown function that could be collar proteins. Subsequently, using various comprehensive approaches, we identified a tetratricopeptide repeat protein BB0236 as a potential candidate for the collar. Biochemical assays indicated that FlbB interacts with BB0236. Furthermore, ∆bb0236 mutant analyses indicated that BB0236 is crucial for collar structure assembly, cellular morphology, motility, orientation of periplasmic flagella and assembly of other flagellar structures. Moreover, using comparative motor analyses, we propose how the collar structure is assembled in B. burgdorferi. Together, our studies provide new insights into the organization and the complex assembly inherent to the unique spirochetal collar structure.
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Affiliation(s)
- Ki Hwan Moon
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Xiaowei Zhao
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston, TX, 77030, USA
| | - Hui Xu
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
| | - Jun Liu
- Department of Pathology and Laboratory Medicine, University of Texas Health Science Center, Houston, TX, 77030, USA.,Department of Microbial Pathogenesis, Microbial Sciences Institute, Yale University, New Haven, CT, 06536, USA
| | - Md A Motaleb
- Department of Microbiology and Immunology, Brody School of Medicine, East Carolina University, Greenville, NC, 27834, USA
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Das C, Mokashi C, Mande SS, Saini S. Dynamics and Control of Flagella Assembly in Salmonella typhimurium. Front Cell Infect Microbiol 2018; 8:36. [PMID: 29473025 PMCID: PMC5809477 DOI: 10.3389/fcimb.2018.00036] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2017] [Accepted: 01/25/2018] [Indexed: 11/13/2022] Open
Abstract
The food-borne pathogen Salmonella typhimurium is a common cause of infections and diseases in a wide range of hosts. One of the major virulence factors associated to the infection process is flagella, which helps the bacterium swim to its preferred site of infection inside the host, the M-cells (Microfold cells) lining the lumen of the small intestine. The expression of flagellar genes is controlled by an intricate regulatory network. In this work, we investigate two aspects of flagella regulation and assembly: (a) distribution of the number of flagella in an isogenic population of bacteria and (b) dynamics of gene expression post cell division. More precisely, in a population of bacteria, we note a normal distribution of number of flagella assembled per cell. How is this distribution controlled, and what are the key regulators in the network which help the cell achieve this? In the second question, we explore the role of protein secretion in dictating gene expression dynamics post cell-division (when the number of hook basal bodies on the cell surface is reduced by a factor of two). We develop a mathematical model and perform stochastic simulations to address these questions. Simulations of the model predict that two accessory regulators of flagella gene expression, FliZ and FliT, have significant roles in maintaining population level distribution of flagella. In addition, FliT and FlgM were predicted to control the level and temporal order of flagellar gene expression when the cell adapts to post cell division consequences. Further, the model predicts that, the FliZ and FliT dependent feedback loops function under certain thresholds, alterations in which can substantially affect kinetics of flagellar genes. Thus, based on our results we propose that, the proteins FlgM, FliZ, and FliT, thought to have accessory roles in regulation of flagella, likely play a critical role controlling gene expression during cell division, and frequency distribution of flagella.
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Affiliation(s)
- Chandrani Das
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India.,Bio-Sciences R&D Division, TCS Research, Tata Consultancy Services Limited, Pune, India
| | - Chaitanya Mokashi
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
| | - Sharmila S Mande
- Bio-Sciences R&D Division, TCS Research, Tata Consultancy Services Limited, Pune, India
| | - Supreet Saini
- Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, India
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13
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Fungal networks shape dynamics of bacterial dispersal and community assembly in cheese rind microbiomes. Nat Commun 2018; 9:336. [PMID: 29362365 PMCID: PMC5780524 DOI: 10.1038/s41467-017-02522-z] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Accepted: 12/07/2017] [Indexed: 11/29/2022] Open
Abstract
Most studies of bacterial motility have examined small-scale (micrometer–centimeter) cell dispersal in monocultures. However, bacteria live in multispecies communities, where interactions with other microbes may inhibit or facilitate dispersal. Here, we demonstrate that motile bacteria in cheese rind microbiomes use physical networks created by filamentous fungi for dispersal, and that these interactions can shape microbial community structure. Serratia proteamaculans and other motile cheese rind bacteria disperse on fungal networks by swimming in the liquid layers formed on fungal hyphae. RNA-sequencing, transposon mutagenesis, and comparative genomics identify potential genetic mechanisms, including flagella-mediated motility, that control bacterial dispersal on hyphae. By manipulating fungal networks in experimental communities, we demonstrate that fungal-mediated bacterial dispersal can shift cheese rind microbiome composition by promoting the growth of motile over non-motile community members. Our single-cell to whole-community systems approach highlights the interactive dynamics of bacterial motility in multispecies microbiomes. Interactions with other microbes may inhibit or facilitate the dispersal of bacteria. Here, Zhang et al. use cheese rind microbiomes as a model to show that physical networks created by filamentous fungi can affect the dispersal of motile bacteria and thus shape the diversity of microbial communities.
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14
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Liu Y, Zhang DF, Zhou X, Xu L, Zhang L, Shi X. Comprehensive Analysis Reveals Two Distinct Evolution Patterns of Salmonella Flagellin Gene Clusters. Front Microbiol 2017; 8:2604. [PMID: 29312269 PMCID: PMC5744181 DOI: 10.3389/fmicb.2017.02604] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2017] [Accepted: 12/14/2017] [Indexed: 11/13/2022] Open
Abstract
Salmonella is one of the primary causes of foodborne disease, especially Salmonella enterica subsp. enterica (I) which has caused ~99% of clinical salmonellosis cases for humans and domestic mammals. The flagella genes, fliC and fljB, which encode the Salmonella phase 1 and phase 2 antigens respectively, are considered as the Salmonella serotype determinant genes, and contribute to the virulence of Salmonella. However, the evolution of the two flagellin genes is still not well-understood. In this study, the fliC and fljB gene clusters were analyzed among 205 S. enterica subspecies I genomes. The dataset covered 87 different serovars of S. enterica subsp. enterica and included 9 genomes (six serovars) of four other Salmonella subspecies. Based on a pan-genome definition and flanked gene linkages, the fliC and fljB gene clusters were identified in 207 (91 serovars) and 138 (61 serovars) genomes, respectively. A phylogenetic tree constructed based on SNPs (Single Nucleotide Polymorphisms) of core genes were used to reflect the essential evolutionary relationships among various serovars. Congruence analysis was performed among the core genome and each gene of fliC and fljB gene clusters, with only fliA and fliS showing congruence to Salmonella core genome. Congruence was also observed among fliB, fliC/fljB, and fliD genes, and their phylogeny revealed a division into two major groups, which strongly corresponded to monophasic and biphasic serovars. Besides, homologous recombination events referring fliB, fliC, and fliD were found to have mainly occurred within each group. These results suggested two distinct evolutionary patterns of Salmonella flagellin gene clusters. Further insight on the evolutionary implication of the two patterns and a framework for phase variation mechanism are needed to be further processed.
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Affiliation(s)
- Yue Liu
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Dao-Feng Zhang
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Xiujuan Zhou
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Li Xu
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Lida Zhang
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
| | - Xianming Shi
- MOST-USDA Joint Research Center for Food Safety, School of Agriculture and Biology, and State Key Laboratory of Microbial Metabolism, Shanghai Jiao Tong University, Shanghai, China
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15
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Yu C, Chen H, Tian F, Yang F, He C. RpoN2- and FliA-regulated fliTX is indispensible for flagellar motility and virulence in Xanthomonas oryzae pv. oryzae. BMC Microbiol 2017; 17:171. [PMID: 28793882 PMCID: PMC5550985 DOI: 10.1186/s12866-017-1083-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2017] [Accepted: 08/02/2017] [Indexed: 12/26/2022] Open
Abstract
Background Bacterial blight of rice caused by Xanthomonas oryzae pv. oryzae (Xoo) is one of the most important crop diseases in the world. More insights into the mechanistic regulation of bacterial pathogenesis will help us identify novel molecular targets for developing effective disease control strategies. A large flagellar gene cluster is regulated under a three-tiered hierarchy by σ54 factor RpoN2 and its activator FleQ, and σ28 factor FliA. A hypothetical protein gene fliTX is located upstream of rpoN2, however, how it is regulated and how it is related to bacterial behaviors remain to be elucidated. Results Sequence alignment analysis indicated that FliTX in Xoo is less well conserved compared with FliT proteins in Escherichia coli, Salmonella typhimurium, and Pseudomonas fluorescens. Co-transcription of fliTX with a cytosolic chaperone gene fliS and an atypical PilZ-domain gene flgZ in an operon was up-regulated by RpoN2/FleQ and FliA. Significantly shorter filament length and impaired swimming motility were observed in ∆fliTX compared with those in the wildtype strain. ∆fliTX also demonstrated reduced disease lesion length and in planta growth in rice, attenuated ability of induction of hypersensitive response (HR) in nonhost tobacco, and down-regulation of type III secretion system (T3SS)-related genes. In trans expression of fliTX gene in ∆fliTX restored these phenotypes to near wild-type levels. Conclusions This study demonstrates that RpoN2- and FliA-regulated fliTX is indispensible for flagellar motility and virulence and provides more insights into mechanistic regulation of T3SS expression in Xoo. Electronic supplementary material The online version of this article (doi:10.1186/s12866-017-1083-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Chao Yu
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Huamin Chen
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Fang Tian
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Fenghuan Yang
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China
| | - Chenyang He
- State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, 100193, China.
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16
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Radomska KA, Wösten MMSM, Ordoñez SR, Wagenaar JA, van Putten JPM. Importance of Campylobacter jejuni FliS and FliW in Flagella Biogenesis and Flagellin Secretion. Front Microbiol 2017; 8:1060. [PMID: 28659885 PMCID: PMC5466977 DOI: 10.3389/fmicb.2017.01060] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Accepted: 05/29/2017] [Indexed: 12/11/2022] Open
Abstract
Flagella-driven motility enables bacteria to reach their favorable niche within the host. The human foodborne pathogen Campylobacter jejuni produces two heavily glycosylated structural flagellins (FlaA and FlaB) that form the flagellar filament. It also encodes the non-structural FlaC flagellin which is secreted through the flagellum and has been implicated in host cell invasion. The mechanisms that regulate C. jejuni flagellin biogenesis and guide the proteins to the export apparatus are different from those in most other enteropathogens and are not fully understood. This work demonstrates the importance of the putative flagellar protein FliS in C. jejuni flagella assembly. A constructed fliS knockout strain was non-motile, displayed reduced levels of FlaA/B and FlaC flagellin, and carried severely truncated flagella. Pull-down and Far Western blot assays showed direct interaction of FliS with all three C. jejuni flagellins (FlaA, FlaB, and FlaC). This is in contrast to, the sensor and regulator of intracellular flagellin levels, FliW, which bound to FlaA and FlaB but not to FlaC. The FliS protein but not FliW preferred binding to glycosylated C. jejuni flagellins rather than to their non-glycosylated recombinant counterparts. Mapping of the binding region of FliS and FliW using a set of flagellin fragments showed that the C-terminal subdomain of the flagellin was required for FliS binding, whereas the N-terminal subdomain was essential for FliW binding. The separate binding subdomains required for FliS and FliW, the different substrate specificity, and the differential preference for binding of glycosylated flagellins ensure optimal processing and assembly of the C. jejuni flagellins.
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Affiliation(s)
- Katarzyna A Radomska
- Department of Infectious Diseases and Immunology, Utrecht UniversityUtrecht, Netherlands
| | - Marc M S M Wösten
- Department of Infectious Diseases and Immunology, Utrecht UniversityUtrecht, Netherlands
| | - Soledad R Ordoñez
- Department of Infectious Diseases and Immunology, Utrecht UniversityUtrecht, Netherlands
| | - Jaap A Wagenaar
- Department of Infectious Diseases and Immunology, Utrecht UniversityUtrecht, Netherlands.,Wageningen Bioveterinary ResearchLelystad, Netherlands.,WHO Collaborating Centre for Campylobacter/OIE Reference Laboratory for CampylobacteriosisUtrecht, Netherlands
| | - Jos P M van Putten
- Department of Infectious Diseases and Immunology, Utrecht UniversityUtrecht, Netherlands.,WHO Collaborating Centre for Campylobacter/OIE Reference Laboratory for CampylobacteriosisUtrecht, Netherlands
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17
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Furukawa Y, Inoue Y, Sakaguchi A, Mori Y, Fukumura T, Miyata T, Namba K, Minamino T. Structural stability of flagellin subunit affects the rate of flagellin export in the absence of FliS chaperone. Mol Microbiol 2016; 102:405-416. [PMID: 27461872 DOI: 10.1111/mmi.13469] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/19/2016] [Indexed: 12/17/2022]
Abstract
FliS chaperone binds to flagellin FliC in the cytoplasm and transfers FliC to a sorting platform of the flagellar type III export apparatus through the interaction between FliS and FlhA for rapid and efficient protein export during flagellar filament assembly. FliS also suppresses the secretion of an anti-σ factor, FlgM. Loss of FliS results in a short filament phenotype although the expression levels of FliC are increased considerably due to an increase in the secretion level of FlgM. Here to clarify the rate limiting step of FliC export in the absence of FliS, we isolated bypass mutants from a Salmonella ΔfliS mutant. All the bypass mutations were identified in FliC. These bypass mutations increased the export rate of FliC by ca. twofold, allowing the bypass mutant cells to produce longer filaments than the parental ΔfliS cells. Both far-UV CD measurements and limited proteolysis revealed that the bypass mutations significantly destabilize the folded structure of FliC monomer. These results suggest that an unfolding step of FliC limits the export rate of FliC in the ΔfliS mutant, thereby producing short filaments. We propose that FliS promotes FliC docking at the FlhA platform to facilitate subsequent unfolding of FliC.
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Affiliation(s)
- Yukio Furukawa
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Yumi Inoue
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Aya Sakaguchi
- Department of Food Science and Nutrition, Faculty of Human Life and Science, Doshisha Women's College of Liberal Arts, Kyoto, 602-0893, Japan
| | - Yoko Mori
- Department of Food Science and Nutrition, Faculty of Human Life and Science, Doshisha Women's College of Liberal Arts, Kyoto, 602-0893, Japan
| | - Takuma Fukumura
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Tomoko Miyata
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.,Quantitative Biology Center, RIKEN, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan. .,Quantitative Biology Center, RIKEN, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan.
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18
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Gupta SK, Gross R, Dandekar T. An antibiotic target ranking and prioritization pipeline combining sequence, structure and network-based approaches exemplified for Serratia marcescens. Gene 2016; 591:268-278. [PMID: 27425866 DOI: 10.1016/j.gene.2016.07.030] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2016] [Revised: 06/26/2016] [Accepted: 07/12/2016] [Indexed: 01/20/2023]
Abstract
We investigate a drug target screening pipeline comparing sequence, structure and network-based criteria for prioritization. Serratia marcescens, an opportunistic pathogen, serves as test case. We rank according to (i) availability of three dimensional structures and lead compounds, (ii) not occurring in man and general sequence conservation information, and (iii) network information on the importance of the protein (conserved protein-protein interactions; metabolism; reported to be an essential gene in other organisms). We identify 45 potential anti-microbial drug targets in S. marcescens with KdsA involved in LPS biosynthesis as top candidate drug target. LpxC and FlgB are further top-ranked targets identified by interactome analysis not suggested before for S. marcescens. Pipeline, targets and complementarity of the three approaches are evaluated by available experimental data and genetic evidence and against other antibiotic screening pipelines. This supports reliable drug target identification and prioritization for infectious agents (bacteria, parasites, fungi) by these bundled complementary criteria.
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Affiliation(s)
- Shishir K Gupta
- Department of Bioinformatics, Biocenter, Am Hubland, D-97074 Würzburg, Germany; Department of Microbiology, Biocenter, Am Hubland, D-97074 Würzburg, Germany.
| | - Roy Gross
- Department of Microbiology, Biocenter, Am Hubland, D-97074 Würzburg, Germany.
| | - Thomas Dandekar
- Department of Bioinformatics, Biocenter, Am Hubland, D-97074 Würzburg, Germany; EMBL Heidelberg, BioComputing Unit, Meyerhofstraße 1, 69117 Heidelberg, Germany.
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19
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Kulshreshtha G, Borza T, Rathgeber B, Stratton GS, Thomas NA, Critchley A, Hafting J, Prithiviraj B. Red Seaweeds Sarcodiotheca gaudichaudii and Chondrus crispus down Regulate Virulence Factors of Salmonella Enteritidis and Induce Immune Responses in Caenorhabditis elegans. Front Microbiol 2016; 7:421. [PMID: 27065981 PMCID: PMC4814495 DOI: 10.3389/fmicb.2016.00421] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2016] [Accepted: 03/16/2016] [Indexed: 11/23/2022] Open
Abstract
Red seaweeds are a rich source of unique bioactive compounds and secondary metabolites that are known to improve human and animal health. S. Enteritidis is a broad range host pathogen, which contaminates chicken and poultry products that end into the human food chain. Worldwide, Salmonella outbreaks have become an important economic and public health concern. Moreover, the development of resistance in Salmonella serovars toward multiple drugs highlights the need for alternative control strategies. This study evaluated the antimicrobial property of red seaweeds extracts against Salmonella Enteritidis using the Caenorhabditis elegans infection model. Six red seaweed species were tested for their antimicrobial activity against S. Enteritidis and two, Sarcodiotheca gaudichaudii (SG) and Chondrus crispus (CC), were found to exhibit such properties. Spread plate assay revealed that SG and CC (1%, w/v) significantly reduced the growth of S. Enteritidis. Seaweed water extracts (SWE) of SG and CC, at concentrations from 0.4 to 2 mg/ml, significantly reduced the growth of S. Enteritidis (log CFU 4.5–5.3 and log 5.7–6.0, respectively). However, methanolic extracts of CC and SG did not affect the growth of S. Enteritidis. Addition of SWE (0.2 mg/ml, CC and SG) significantly decreased biofilm formation and reduced the motility of S. Enteritidis. Quantitative real-time PCR analyses showed that SWE (CC and SG) suppressed the expression of quorum sensing gene sdiA and of Salmonella Pathogenesis Island-1 (SPI-1) associated genes sipA and invF, indicating that SWE might reduce the invasion of S. Enteritidis in the host by attenuating virulence factors. Furthermore, CC and SG water extracts significantly improved the survival of infected C. elegans by impairing the ability of S. Enteritidis to colonize the digestive tract of the nematode and by enhancing the expression of C. elegans immune responsive genes. As the innate immune response pathways of C. elegans and mammals show a high degree of conservation, these results suggest that these SWE may also impart beneficial effects on animal and human health.
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Affiliation(s)
- Garima Kulshreshtha
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie UniversityTruro, NS, Canada; Acadian Seaplants LimitedDartmouth, NS, Canada
| | - Tudor Borza
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada
| | - Bruce Rathgeber
- Department of Plant and Animal Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada
| | - Glenn S Stratton
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada
| | - Nikhil A Thomas
- Department of Microbiology and Immunology, Faculty of Medicine, Dalhousie University Halifax, NS, Canada
| | | | | | - Balakrishnan Prithiviraj
- Department of Environmental Sciences, Faculty of Agriculture, Dalhousie University Truro, NS, Canada
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20
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Cesbron S, Briand M, Essakhi S, Gironde S, Boureau T, Manceau C, Fischer-Le Saux M, Jacques MA. Comparative Genomics of Pathogenic and Nonpathogenic Strains of Xanthomonas arboricola Unveil Molecular and Evolutionary Events Linked to Pathoadaptation. FRONTIERS IN PLANT SCIENCE 2015; 6:1126. [PMID: 26734033 DOI: 10.3389/fpls.2015.01126.ecollection2015] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 11/27/2015] [Indexed: 05/24/2023]
Abstract
The bacterial species Xanthomonas arboricola contains plant pathogenic and nonpathogenic strains. It includes the pathogen X. arboricola pv. juglandis, causing the bacterial blight of Juglans regia. The emergence of a new bacterial disease of J. regia in France called vertical oozing canker (VOC) was previously described and the causal agent was identified as a distinct genetic lineage within the pathovar juglandis. Symptoms on walnut leaves and fruits are similar to those of a bacterial blight but VOC includes also cankers on trunk and branches. In this work, we used comparative genomics and physiological tests to detect differences between four X. arboricola strains isolated from walnut tree: strain CFBP 2528 causing walnut blight (WB), strain CFBP 7179 causing VOC and two nonpathogenic strains, CFBP 7634 and CFBP 7651, isolated from healthy walnut buds. Whole genome sequence comparisons revealed that pathogenic strains possess a larger and wider range of mobile genetic elements than nonpathogenic strains. One pathogenic strain, CFBP 7179, possessed a specific integrative and conjugative element (ICE) of 95 kb encoding genes involved in copper resistance, transport and regulation. The type three effector repertoire was larger in pathogenic strains than in nonpathogenic strains. Moreover, CFBP 7634 strain lacked the type three secretion system encoding genes. The flagellar system appeared incomplete and nonfunctional in the pathogenic strain CFBP 2528. Differential sets of chemoreceptor and different repertoires of genes coding adhesins were identified between pathogenic and nonpathogenic strains. Besides these differences, some strain-specific differences were also observed. Altogether, this study provides valuable insights to highlight the mechanisms involved in ecology, environment perception, plant adhesion and interaction, leading to the emergence of new strains in a dynamic environment.
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Affiliation(s)
- Sophie Cesbron
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences Beaucouzé, France
| | - Martial Briand
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences Beaucouzé, France
| | - Salwa Essakhi
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences Beaucouzé, France
| | - Sophie Gironde
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences Beaucouzé, France
| | - Tristan Boureau
- Université d'Angers, UMR 1345 Institut de Recherche en Horticulture et Semences Angers, France
| | - Charles Manceau
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences Beaucouzé, France
| | | | - Marie-Agnès Jacques
- INRA, UMR 1345 Institut de Recherche en Horticulture et Semences Beaucouzé, France
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21
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More than a locomotive organelle: flagella in Escherichia coli. Appl Microbiol Biotechnol 2015; 99:8883-90. [DOI: 10.1007/s00253-015-6946-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2015] [Revised: 08/17/2015] [Accepted: 08/20/2015] [Indexed: 10/23/2022]
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22
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Mathematical model of flagella gene expression dynamics in Salmonella enterica serovar typhimurium. SYSTEMS AND SYNTHETIC BIOLOGY 2015; 9:19-31. [PMID: 25972986 DOI: 10.1007/s11693-015-9160-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 10/11/2014] [Accepted: 01/21/2015] [Indexed: 01/11/2023]
Abstract
Flagellar assembly in Salmonella is controlled by an intricate genetic and biochemical network. This network comprises of a number of inter-connected feedback loops, which control the assembly process dynamically. Critical among these are the FliA-FlgM feedback, FliZ-mediated positive feedback, and FliT-mediated negative feedback. In this work, we develop a mathematical model to track the dynamics of flagellar gene expression in Salmonella. Analysis of our model demonstrates that the network is wired to not only control the transition of the cell from a non-flagellated to a flagellated state, but to also control dynamics of gene expression during cell division. Further, we predict that FliZ encoded in the flagellar regulon acts as a critical secretion-dependent molecular link between flagella and Salmonella Pathogenicity Island 1 gene expression. Sensitivity analysis of the model demonstrates that the flagellar regulatory network architecture is extremely robust to mutations.
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23
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Cesbron S, Briand M, Essakhi S, Gironde S, Boureau T, Manceau C, Fischer-Le Saux M, Jacques MA. Comparative Genomics of Pathogenic and Nonpathogenic Strains of Xanthomonas arboricola Unveil Molecular and Evolutionary Events Linked to Pathoadaptation. FRONTIERS IN PLANT SCIENCE 2015; 6:1126. [PMID: 26734033 PMCID: PMC4686621 DOI: 10.3389/fpls.2015.01126] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2015] [Accepted: 11/27/2015] [Indexed: 05/03/2023]
Abstract
The bacterial species Xanthomonas arboricola contains plant pathogenic and nonpathogenic strains. It includes the pathogen X. arboricola pv. juglandis, causing the bacterial blight of Juglans regia. The emergence of a new bacterial disease of J. regia in France called vertical oozing canker (VOC) was previously described and the causal agent was identified as a distinct genetic lineage within the pathovar juglandis. Symptoms on walnut leaves and fruits are similar to those of a bacterial blight but VOC includes also cankers on trunk and branches. In this work, we used comparative genomics and physiological tests to detect differences between four X. arboricola strains isolated from walnut tree: strain CFBP 2528 causing walnut blight (WB), strain CFBP 7179 causing VOC and two nonpathogenic strains, CFBP 7634 and CFBP 7651, isolated from healthy walnut buds. Whole genome sequence comparisons revealed that pathogenic strains possess a larger and wider range of mobile genetic elements than nonpathogenic strains. One pathogenic strain, CFBP 7179, possessed a specific integrative and conjugative element (ICE) of 95 kb encoding genes involved in copper resistance, transport and regulation. The type three effector repertoire was larger in pathogenic strains than in nonpathogenic strains. Moreover, CFBP 7634 strain lacked the type three secretion system encoding genes. The flagellar system appeared incomplete and nonfunctional in the pathogenic strain CFBP 2528. Differential sets of chemoreceptor and different repertoires of genes coding adhesins were identified between pathogenic and nonpathogenic strains. Besides these differences, some strain-specific differences were also observed. Altogether, this study provides valuable insights to highlight the mechanisms involved in ecology, environment perception, plant adhesion and interaction, leading to the emergence of new strains in a dynamic environment.
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Affiliation(s)
- Sophie Cesbron
- INRA, UMR 1345 Institut de Recherche en Horticulture et SemencesBeaucouzé, France
- *Correspondence: Sophie Cesbron
| | - Martial Briand
- INRA, UMR 1345 Institut de Recherche en Horticulture et SemencesBeaucouzé, France
| | - Salwa Essakhi
- INRA, UMR 1345 Institut de Recherche en Horticulture et SemencesBeaucouzé, France
| | - Sophie Gironde
- INRA, UMR 1345 Institut de Recherche en Horticulture et SemencesBeaucouzé, France
| | - Tristan Boureau
- Université d'Angers, UMR 1345 Institut de Recherche en Horticulture et SemencesAngers, France
| | - Charles Manceau
- INRA, UMR 1345 Institut de Recherche en Horticulture et SemencesBeaucouzé, France
| | | | - Marie-Agnès Jacques
- INRA, UMR 1345 Institut de Recherche en Horticulture et SemencesBeaucouzé, France
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24
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Barrero-Tobon AM, Hendrixson DR. Flagellar biosynthesis exerts temporal regulation of secretion of specific Campylobacter jejuni colonization and virulence determinants. Mol Microbiol 2014; 93:957-74. [PMID: 25041103 DOI: 10.1111/mmi.12711] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/08/2014] [Indexed: 01/26/2023]
Abstract
The Campylobacter jejuni flagellum exports both proteins that form the flagellar organelle for swimming motility and colonization and virulence factors that promote commensal colonization of the avian intestinal tract or invasion of human intestinal cells respectively. We explored how the C. jejuni flagellum is a versatile secretory organelle by examining molecular determinants that allow colonization and virulence factors to exploit the flagellum for their own secretion. Flagellar biogenesis was observed to exert temporal control of secretion of these proteins, indicating that a bolus of secretion of colonization and virulence factors occurs during hook biogenesis with filament polymerization itself reducing secretion of these factors. Furthermore, we found that intramolecular and intermolecular requirements for flagellar-dependent secretion of these proteins were most reminiscent to those for flagellin secretion. Importantly, we discovered that secretion of one colonization and virulence factor, CiaI, was not required for invasion of human colonic cells, which counters previous hypotheses for how this protein functions during invasion. Instead, secretion of CiaI was essential for C. jejuni to facilitate commensal colonization of the natural avian host. Our work provides insight into the versatility of the bacterial flagellum as a secretory machine that can export proteins promoting diverse biological processes.
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Affiliation(s)
- Angelica M Barrero-Tobon
- Department of Microbiology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Room NL 4.138A, Dallas, TX, 75390-9048, USA
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25
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Sajó R, Liliom K, Muskotál A, Klein A, Závodszky P, Vonderviszt F, Dobó J. Soluble components of the flagellar export apparatus, FliI, FliJ, and FliH, do not deliver flagellin, the major filament protein, from the cytosol to the export gate. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2014; 1843:2414-23. [PMID: 25068520 DOI: 10.1016/j.bbamcr.2014.07.004] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2014] [Revised: 07/01/2014] [Accepted: 07/11/2014] [Indexed: 12/21/2022]
Abstract
Flagella, the locomotion organelles of bacteria, extend from the cytoplasm to the cell exterior. External flagellar proteins are synthesized in the cytoplasm and exported by the flagellar type III secretion system. Soluble components of the flagellar export apparatus, FliI, FliH, and FliJ, have been implicated to carry late export substrates in complex with their cognate chaperones from the cytoplasm to the export gate. The importance of the soluble components in the delivery of the three minor late substrates FlgK, FlgL (hook-filament junction) and FliD (filament-cap) has been convincingly demonstrated, but their role in the transport of the major filament component flagellin (FliC) is still unclear. We have used continuous ATPase activity measurements and quartz crystal microbalance (QCM) studies to characterize interactions between the soluble export components and flagellin or the FliC:FliS substrate-chaperone complex. As controls, interactions between soluble export component pairs were characterized providing Kd values. FliC or FliC:FliS did not influence the ATPase activity of FliI alone or in complex with FliH and/or FliJ suggesting lack of interaction in solution. Immobilized FliI, FliH, or FliJ did not interact with FliC or FliC:FliS detected by QCM. The lack of interaction in the fluid phase between FliC or FliC:FliS and the soluble export components, in particular with the ATPase FliI, suggests that cells use different mechanisms for the export of late minor substrates, and the major substrate, FliC. It seems that the abundantly produced flagellin does not require the assistance of the soluble export components to efficiently reach the export gate.
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Affiliation(s)
- Ráchel Sajó
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok krt. 2, H-1117 Budapest, Hungary
| | - Károly Liliom
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok krt. 2, H-1117 Budapest, Hungary
| | - Adél Muskotál
- Bio-Nanosystems Laboratory, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary
| | - Agnes Klein
- Bio-Nanosystems Laboratory, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary
| | - Péter Závodszky
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok krt. 2, H-1117 Budapest, Hungary
| | - Ferenc Vonderviszt
- Bio-Nanosystems Laboratory, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, H-8200 Veszprém, Hungary
| | - József Dobó
- Institute of Enzymology, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok krt. 2, H-1117 Budapest, Hungary.
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26
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Analysis of factors that affect FlgM-dependent type III secretion for protein purification with Salmonella enterica serovar Typhimurium. J Bacteriol 2014; 196:2333-47. [PMID: 24706743 DOI: 10.1128/jb.01572-14] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The FlgM protein is secreted in response to flagellar hook-basal body secretion and can be used as a secretion signal to direct selected protein secretion via the flagellar type III secretion (T3S) system [H. M. Singer, M. Erhardt, A. M. Steiner, M. M. Zhang, D. Yoshikami, G. Bulaj, B. M. Olivera, and K. T. Hughes, mBio 3(3):e00115-12, 2012, http://dx.doi.org/10.1128/mBio.00115-12]. Conditions known to affect flagellar gene expression, FlgM stability, and flagellar T3S were tested either alone or in combination to determine their effects on levels of secreted FlgM. These conditions included mutations that affect activity of the flagellar FlhD4C2 master regulatory protein complex or the FlgM T3S chaperone σ(28), the removal of Salmonella pathogenicity island 1 (Spi1), the removal of flagellar late secretion substrates that could compete with FlgM for secretion, and changes in the ionic strength of the growth medium. Conditions that enhanced FlgM secretion were combined in order to maximize levels of secreted FlgM. An optimized FlgM secretion strain was used to secrete and isolate otherwise difficult-to-produce proteins and peptides fused to the C terminus of FlgM. These include cysteine-rich, hydrophobic peptides (conotoxins δ-SVIE and MrVIA), nodule-specific, cysteine-rich antimicrobial peptides (NCR), and a malaria surface antigen domain of apical membrane antigen AMA-1.
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27
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Chan JM, Guttenplan SB, Kearns DB. Defects in the flagellar motor increase synthesis of poly-γ-glutamate in Bacillus subtilis. J Bacteriol 2014; 196:740-53. [PMID: 24296669 PMCID: PMC3911173 DOI: 10.1128/jb.01217-13] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 11/25/2013] [Indexed: 12/20/2022] Open
Abstract
Bacillus subtilis swims in liquid media and swarms over solid surfaces, and it encodes two sets of flagellar stator homologs. Here, we show that B. subtilis requires only the MotA/MotB stator during swarming motility and that the residues required for stator force generation are highly conserved from the Proteobacteria to the Firmicutes. We further find that mutants that abolish stator function also result in an overproduction of the extracellular polymer poly-γ-glutamate (PGA) to confer a mucoid colony phenotype. PGA overproduction appeared to be the result of an increase in the expression of the pgs operon that encodes genes for PGA synthesis. Transposon mutagenesis was conducted to identify insertions that abolished colony mucoidy and disruptions in known transcriptional regulators of PGA synthesis (Com and Deg two-component systems) as well as mutants defective in transcription-coupled DNA repair (Mfd)-reduced expression of the pgs operon. A final class of insertions disrupted proteins involved in the assembly of the flagellar filament (FliD, FliT, and FlgL), and these mutants did not reduce expression of the pgs operon, suggesting a second mechanism of PGA control.
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Affiliation(s)
- Jia Mun Chan
- Indiana University, Department of Biology, Bloomington, Indiana, USA
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28
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Kinoshita M, Hara N, Imada K, Namba K, Minamino T. Interactions of bacterial flagellar chaperone-substrate complexes with FlhA contribute to co-ordinating assembly of the flagellar filament. Mol Microbiol 2013; 90:1249-61. [PMID: 24325251 DOI: 10.1111/mmi.12430] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/13/2013] [Indexed: 11/29/2022]
Abstract
Assembly of the bacterial flagellar filament is strictly sequential; the junction proteins, FlgK and FlgL, are assembled at the distal end of the hook prior to the FliD cap, which supports assembly of as many as 30 000 FliC molecules into the filament. Export of these proteins requires assistance of flagellar chaperones: FlgN for FlgK and FlgL, FliT for FliD and FliS for FliC. The C-terminal cytoplasmic domain of FlhA (FlhAC ), a membrane component of the export apparatus, provides a binding-site for these chaperone-substrate complexes but it remains unknown how it co-ordinates flagellar protein export. Here, we report that the highly conserved hydrophobic dimple of FlhAC is involved in the export of FlgK, FlgL, FliD and FliC but not in proteins responsible for the structure and assembly of the hook, and that the binding affinity of FlhAC for the FlgN/FlgK complex is slightly higher than that for the FliT/FliD complex and about 14-fold higher than that for the FliS/FliC complex, leading to the proposal that the different binding affinities of FlhAC for these chaperone/substrate complexes may confer an advantage for the efficient formation of the junction and cap structures at the tip of the hook prior to filament formation.
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Affiliation(s)
- Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka, 565-0871, Japan
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29
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Xu S, Peng Z, Cui B, Wang T, Song Y, Zhang L, Wei G, Wang Y, Shen X. FliS modulates FlgM activity by acting as a non-canonical chaperone to control late flagellar gene expression, motility and biofilm formation in Yersinia pseudotuberculosis. Environ Microbiol 2013; 16:1090-104. [PMID: 23957589 DOI: 10.1111/1462-2920.12222] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2013] [Accepted: 07/19/2013] [Indexed: 12/01/2022]
Abstract
The FlgM-FliA regulatory circuit plays a central role in coordinating bacterial flagellar assembly. In this study, we identified multiple novel binding partners of FlgM using bacterial two-hybrid screening. Among these binding partners, FliS, the secretion chaperone of the filament protein FliC, was identified to compete with FliA for the binding of FlgM. We further showed that by binding to FlgM, FliS protects it from secretion and degradation, thus maintaining an intracellular pool of FlgM reserved as the FliS-FlgM complex. Consequently, we found that the flagellar late-class promoter activities are significantly increased in the fliS deletion mutant. The fliS mutant is weakly motile and shows significantly increased biofilm formation on biotic surface. Based on the results obtained, we established for the first time the regulatory role of the flagellin chaperone FliS to fine-tune late flagellar assembly by modulating FlgM activity.
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Affiliation(s)
- Shengjuan Xu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China; Wuhan Institute of Virology, Chinese Academy of Sciences, Wuhan, 430071, China
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30
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FliW and FliS function independently to control cytoplasmic flagellin levels in Bacillus subtilis. J Bacteriol 2012; 195:297-306. [PMID: 23144244 DOI: 10.1128/jb.01654-12] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The cytoplasmic level of flagellin (called Hag) is homeostatically regulated in the Gram-positive bacterium Bacillus subtilis by a partner-switching mechanism between the protein FliW and either the Hag structural protein or CsrA, an RNA binding protein that represses hag translation. Here we show that FliW and the putative secretion chaperone FliS bind to Hag simultaneously but control Hag translation by different mechanisms. While FliW directly inhibits CsrA activity, FliS antagonizes CsrA indirectly by binding to Hag, enhancing Hag secretion, and depleting Hag in the cytoplasm to trigger the FliW partner switch. Consistent with a role for FliS in potentiating Hag secretion, the mutation of fliS crippled both motility and flagellar filament assembly, and both phenotypes could be partially rescued by artificially increasing the concentration of the Hag substrate through the absence of CsrA. Furthermore, the absence of FliS resulted in an approximately 30-fold reduction in extracellular Hag accumulation in cells mutated for CsrA (to relieve homeostatic control) and the filament cap protein FliD (to secrete flagellin into the supernatant). Thus, we mechanistically discriminate between the FliW regulator and the FliS chaperone to show that secretion disrupts flagellin homeostasis and promotes high-level flagellin synthesis during the period of filament assembly in B. subtilis.
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31
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Lee J, Harshey RM. Loss of FlhE in the flagellar Type III secretion system allows proton influx into Salmonella and Escherichia coli. Mol Microbiol 2012; 84:550-65. [PMID: 22435757 DOI: 10.1111/j.1365-2958.2012.08043.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
flhE belongs to the flhBAE flagellar operon in Enterobacteria, whose first two members function in Type III secretion (T3S). In Salmonella enterica, absence of FlhE affects swarming, but not swimming, motility. Based on a chance observation of a 'green' colony phenotype of flhE mutants on pH indicator plates containing glucose, we have established that this phenotype is associated with lysis of flagellated cells in an acidic environment created by glucose metabolism. The flhE mutant phenotype of Escherichia coli is similar overall to that of S. enterica but is seen in the absence of glucose and, unlike in S. enterica, causes a substantial growth defect. flhE mutants have a lowered cytoplasmic pH in both bacteria, indicative of a proton leak. GFP reporter assays indicate that the leak is dependent on the flagellar system, is present before the T3S system switches to secretion of late substrates, and gets worse after the switch and upon filament assembly, leading to cell lysis. We show that FlhE is a periplasmic protein that co-purifies with flagellar basal bodies. FlhE may act as a plug or a chaperone to regulate proton flow through the flagellar T3S system.
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Affiliation(s)
- Jaemin Lee
- Section of Molecular Genetics and Microbiology & Institute of Cellular and Molecular Biology, University of Texas at Austin, Austin, TX 78712, USA
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32
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Neal-McKinney JM, Konkel ME. The Campylobacter jejuni CiaC virulence protein is secreted from the flagellum and delivered to the cytosol of host cells. Front Cell Infect Microbiol 2012; 2:31. [PMID: 22919623 PMCID: PMC3417660 DOI: 10.3389/fcimb.2012.00031] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2011] [Accepted: 02/29/2012] [Indexed: 12/04/2022] Open
Abstract
Campylobacter jejuni is a leading cause of bacterial gastroenteritis worldwide. Acute C. jejuni-mediated disease (campylobacteriosis) involves C. jejuni invasion of host epithelial cells using adhesins (e.g., CadF and FlpA) and secreted proteins [e.g., the Campylobacter invasion antigens (Cia)]. The genes encoding the Cia proteins are up-regulated upon co-culture of C. jejuni with epithelial cells. One of the Cia proteins, CiaC, is required for maximal invasion of host cells by C. jejuni. Previous work has also revealed that CiaC is, in part, responsible for host cell cytoskeletal rearrangements that result in membrane ruffling. This study was performed to test the hypothesis that CiaC is delivered to the cytosol of host cells. To detect the delivery of CiaC into cultured epithelial cells, we used the adenylate cyclase domain (ACD) of Bordetella pertussis CyaA as a reporter. In this study, we found that export and delivery of the C. jejuni Cia proteins into human INT 407 epithelial cells required a functional flagellar hook complex composed of FlgE, FlgK, and FlgL. Assays performed with bacterial culture supernatants supported the hypothesis that CiaC delivery requires bacteria-host cell contact. We also found that CiaC was delivered to host cells by cell-associated (bound) bacteria, as judged by experiments performed with inhibitors that specifically target the cell signaling pathways utilized by C. jejuni for cell invasion. Interestingly, the C. jejuni flgL mutant, which is incapable of exporting and delivering the Cia proteins, did not induce INT 407 cell membrane ruffles. Complementation of the flgL mutant with plasmid-encoded flgL restored the motility and membrane ruffling. These data support the hypothesis that the C. jejuni Cia proteins, which are exported from the flagellum, are delivered to the cytosol of host cells.
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33
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Buschart A, Sachs S, Chen X, Herglotz J, Krause A, Reinhold-Hurek B. Flagella mediate endophytic competence rather than act as MAMPS in rice-Azoarcus sp. strain BH72 interactions. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2012; 25:191-9. [PMID: 22235904 DOI: 10.1094/mpmi-05-11-0138] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Azoarcus sp. strain BH72 is an endophytic betaproteobacterium able to colonize rice roots without induction of visible disease symptoms. BH72 possesses one polar flagellum. The genome harbors three copies of putative fliC genes, generally encoding the major structural protein flagellin. It is not clear whether, in endophytic interactions, flagella mediate endophytic competence or act as MAMPs (microbe-associated molecular patterns) inducing plant defense responses. Therefore, possible functions of the three FliC proteins were investigated. Only fliC3 was found to be highly expressed in pure culture and in association with rice roots and to be required for bacterial motility, suggesting that it encodes the major flagellin. Endophytic colonization of rice roots was significantly reduced in the in-frame deletion mutant, while the establishment of microcolonies on the root surface was not affected. Moreover, an elicitation of defense responses related to FliC3 was not observed. In conclusion, our data support the hypothesis that FliC3 does not play a major role as a MAMP but is required for endophytic colonization in the Azoarcus-rice interaction, most likely for spreading inside the plant.
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Affiliation(s)
- Anna Buschart
- Department of Microbe-Plant Interactions, University of Bremen, Bremen, Germany
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34
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Vandenbroucke V, Croubels S, Martel A, Verbrugghe E, Goossens J, Van Deun K, Boyen F, Thompson A, Shearer N, De Backer P, Haesebrouck F, Pasmans F. The mycotoxin deoxynivalenol potentiates intestinal inflammation by Salmonella typhimurium in porcine ileal loops. PLoS One 2011; 6:e23871. [PMID: 21909370 PMCID: PMC3166085 DOI: 10.1371/journal.pone.0023871] [Citation(s) in RCA: 77] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Accepted: 07/27/2011] [Indexed: 11/19/2022] Open
Abstract
Background and Aims Both deoxynivalenol (DON) and nontyphoidal salmonellosis are emerging threats with possible hazardous effects on both human and animal health. The objective of this study was to examine whether DON at low but relevant concentrations interacts with the intestinal inflammation induced by Salmonella Typhimurium. Methodology By using a porcine intestinal ileal loop model, we investigated whether intake of low concentrations of DON interacts with the early intestinal inflammatory response induced by Salmonella Typhimurium. Results A significant higher expression of IL-12 and TNFα and a clear potentiation of the expression of IL-1β, IL-8, MCP-1 and IL-6 was seen in loops co-exposed to 1 µg/mL of DON and Salmonella Typhimurium compared to loops exposed to Salmonella Typhimurium alone. This potentiation coincided with a significantly enhanced Salmonella invasion in and translocation over the intestinal epithelial IPEC-J2 cells, exposed to non-cytotoxic concentrations of DON for 24 h. Exposure of Salmonella Typhimurium to 0.250 µg/mL of DON affected the bacterial gene expression level of a limited number of genes, however none of these expression changes seemed to give an explanation for the increased invasion and translocation of Salmonella Typhimurium and the potentiated inflammatory response in combination with DON. Conclusion These data imply that the intake of low and relevant concentrations of DON renders the intestinal epithelium more susceptible to Salmonella Typhimurium with a subsequent potentiation of the inflammatory response in the gut.
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Affiliation(s)
- Virginie Vandenbroucke
- Department of Pharmacology, Toxicology and Biochemistry, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium.
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35
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Engineering and preclinical evaluation of attenuated nontyphoidal Salmonella strains serving as live oral vaccines and as reagent strains. Infect Immun 2011; 79:4175-85. [PMID: 21807911 DOI: 10.1128/iai.05278-11] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
While nontyphoidal Salmonella (NTS) has long been recognized as a cause of self-limited gastroenteritis, it is becoming increasingly evident that multiple-antibiotic-resistant strains are also emerging as important causes of invasive bacteremia and focal infections, resulting in hospitalizations and deaths. We have constructed attenuated Salmonella enterica serovar Typhimurium and Salmonella enterica serovar Enteritidis strains that can serve as live oral vaccines and as "reagent strains" for subunit vaccine production in a safe and economical manner. Prototype attenuated vaccine strains CVD 1921 and CVD 1941, derived from the invasive wild-type strains S. Typhimurium I77 and S. Enteritidis R11, respectively, were constructed by deleting guaBA, encoding guanine biosynthesis, and clpP, encoding a master protease regulator. The clpP mutation resulted in a hyperflagellation phenotype. An additional deletion in fliD yielded reagent strains CVD 1923 and CVD 1943, respectively, which export flagellin monomers. Oral 50% lethal dose (LD₅₀) analyses showed that the NTS vaccine strains were all highly attenuated in mice. Oral immunization with CVD 1921 or CVD 1923 protected mice against lethal challenge with wild-type S. Typhimurium I77. Immunization with CVD 1941 but not CVD 1943 protected mice against lethal infection with S. Enteritidis R11. Immune responses induced by these strains included high levels of serum IgG anti-lipopolysaccharide (LPS) and anti-flagellum antibodies, with titers increasing progressively during the immunization schedule. Since S. Typhimurium and S. Enteritidis are the most common NTS serovars associated with invasive disease, these findings can pave the way for development of a highly effective, broad-spectrum vaccine against invasive NTS.
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36
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FliZ acts as a repressor of the ydiV gene, which encodes an anti-FlhD4C2 factor of the flagellar regulon in Salmonella enterica serovar typhimurium. J Bacteriol 2011; 193:5191-8. [PMID: 21804009 DOI: 10.1128/jb.05441-11] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
YdiV acts as an anti-FlhD4C2 factor, which negatively regulates the class 2 flagellar operons in poor medium in Salmonella enterica serovar Typhimurium. On the other hand, one of the class 2 flagellar genes, fliZ, encodes a positive regulator of the class 2 operons. In this study, we found that the FliZ-dependent activation of class 2 operon expression was more profound in poor medium than in rich medium and not observed in the ydiV mutant background. Transcription of the ydiV gene was shown to increase in the fliZ mutant. Purified FliZ protein was shown in vitro to bind to the promoter region of the nlpC gene, which is located just upstream of the ydiV gene, and to repress its transcription. These results indicate that FliZ is a repressor of the nlpC-ydiV operon and activates the class 2 operons by repressing ydiV expression. Therefore, the fliZ and ydiV genes form a regulatory loop.
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37
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Genetic and molecular characterization of flagellar assembly in Shewanella oneidensis. PLoS One 2011; 6:e21479. [PMID: 21731763 PMCID: PMC3120886 DOI: 10.1371/journal.pone.0021479] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2011] [Accepted: 06/02/2011] [Indexed: 01/17/2023] Open
Abstract
Shewanella oneidensis is a highly motile organism by virtue of a polar flagellum. Unlike most flagellated bacteria, it contains only one major chromosome segment encoding the components of the flagellum with the exception of the motor proteins. In this region, three genes encode flagellinsaccording to the original genome annotation. However, we find that only flaA and flaB encode functional filament subunits. Although these two genesare under the control of different promoters, they are actively transcribed and subsequently translated, producing a considerable number of flagellin proteins. Additionally, both flagellins are able to interact with their chaperon FliS and are subjected to feedback regulation. Furthermore, FlaA and FlaB are glycosylated by a pathwayinvolving a major glycosylating enzyme,PseB, in spite of the lack of the majority of theconsensus glycosylation sites. In conclusion, flagellar assembly in S. oneidensis has novel features despite the conservation of homologous genes across taxa.
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38
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EAL domain protein YdiV acts as an anti-FlhD4C2 factor responsible for nutritional control of the flagellar regulon in Salmonella enterica Serovar Typhimurium. J Bacteriol 2011; 193:1600-11. [PMID: 21278297 DOI: 10.1128/jb.01494-10] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Flagellar operons are divided into three classes with respect to their transcriptional hierarchy in Salmonella enterica serovar Typhimurium. The class 1 gene products FlhD and FlhC act together in an FlhD(4)C(2) heterohexamer, which binds upstream of the class 2 promoters to facilitate binding of RNA polymerase. In this study, we showed that flagellar expression was much reduced in the cells grown in poor medium compared to those grown in rich medium. This nutritional control was shown to be executed at a step after class 1 transcription. We isolated five Tn5 insertion mutants in which the class 2 expression was derepressed in poor medium. These insertions were located in the ydiV (cdgR) gene or a gene just upstream of ydiV. The ydiV gene is known to encode an EAL domain protein and to act as a negative regulator of flagellar expression. Gene disruption and complementation analyses revealed that the ydiV gene is responsible for nutritional control. Expression analysis of the ydiV gene showed that its translation, but not transcription, was enhanced by growth in poor medium. The ydiV mutation did not have a significant effect on either the steady-state level of flhDC mRNA or that of FlhC protein. Purified YdiV protein was shown in vitro to bind to FlhD(4)C(2) through interaction with FlhD subunit and to inhibit its binding to the class 2 promoter, resulting in inhibition of FlhD(4)C(2)-dependent transcription. Taking these data together, we conclude that YdiV is a novel anti-FlhD(4)C(2) factor responsible for nutritional control of the flagellar regulon.
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Lam WWL, Woo EJ, Kotaka M, Tam WK, Leung YC, Ling TKW, Au SWN. Molecular interaction of flagellar export chaperone FliS and cochaperone HP1076 in Helicobacter pylori. FASEB J 2010; 24:4020-32. [PMID: 20581225 DOI: 10.1096/fj.10-155242] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Flagellar export chaperone FliS prevents premature polymerization of flagellins and is critical for flagellar assembly and bacterial colonization. Previously, a yeast 2-hybrid study identified various FliS-associated proteins in Helicobacter pylori, but the implications of these interactions are not known. Here we demonstrate the biophysical interaction of FliS (HP0753) and the uncharacterized protein HP1076 from H. pylori. HP1076 possesses a cochaperone activity that promotes the folding and chaperone activity of FliS. We further determined the crystal structures of FliS, HP1076, and the binary complex at 2.7, 1.8, and 2.7 Å resolution, respectively. HP1076 adopts a helix-rich bundle structure and interestingly shares a similar fold with a flagellin homologue, hook-associated protein, and FliS. The FliS-HP1076 complex revealed an extensive electrostatic and hydrophobic binding interface, which is distinct from the flagellin binding pocket in FliS. The helical stacking interaction between HP1076 and FliS suggests that HP1076 stabilizes 2 α helices of FliS and therefore the overall structure of the bundle. Our findings provide new insights into flagellar export chaperones and may have implications for other secretion chaperones in the type III secretion system.
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Affiliation(s)
- Wendy Wai Ling Lam
- Centre of Protein Science and Crystallography, Department of Biochemistry, Faculty of Science, The Chinese University of Hong Kong, Hong Kong, China
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Kinoshita M, Yamane M, Matsunami H, Minamino T, Namba K, Imada K. Purification, crystallization and preliminary X-ray analysis of FliT, a bacterial flagellar substrate-specific export chaperone. Acta Crystallogr Sect F Struct Biol Cryst Commun 2009; 65:825-8. [PMID: 19652350 PMCID: PMC2720344 DOI: 10.1107/s1744309109026736] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2009] [Accepted: 07/08/2009] [Indexed: 11/10/2022]
Abstract
The assembly process of the bacterial flagellum is coupled to flagellar gene expression. FliT acts not only as a flagellar type III substrate-specific export chaperone for the filament-capping protein FliD but also as a negative regulator that suppresses flagellar gene expression through its specific interaction with the master regulator FlhD(4)C(2) complex. In this study, FliT of Salmonella enterica serovar Typhimurium was expressed, purified and crystallized. Crystals of SeMet FliT were obtained by the sitting-drop vapour-diffusion technique with potassium/sodium tartrate as the precipitant. The crystals grew in the trigonal space group P3(1)21 or P3(2)21 and diffracted to 3.2 A resolution. The anomalous difference Patterson map of the SeMet FliT crystal showed significant peaks in its Harker sections, indicating the usefulness of the derivative data for structure determination.
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Affiliation(s)
- Miki Kinoshita
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Midori Yamane
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Hideyuki Matsunami
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- Trans-membrane Trafficking Unit, Okinawa Institute of Science and Technology, 12-22 Suzaki, Uruma, Okinawa 904-2234, Japan
| | - Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
- PRESTO (Precursory Research for Embryonic Science and Technology), JST, 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
| | - Keiichi Namba
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
| | - Katsumi Imada
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
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Minamino T, Imada K, Namba K. Mechanisms of type III protein export for bacterial flagellar assembly. MOLECULAR BIOSYSTEMS 2008; 4:1105-15. [PMID: 18931786 DOI: 10.1039/b808065h] [Citation(s) in RCA: 149] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Flagellar type III protein export is highly organized and well controlled in a timely manner by dynamic, specific and cooperative interactions among components of the export apparatus, allowing the huge and complex macromolecular assembly to be built efficiently. The bacterial flagellum, which is required for motility, consists of a rotary motor, a universal joint and a helical propeller. Most of the flagellar components are translocated to the distal, growing end of the flagellum for assembly through the central channel of the flagellum itself by the flagellar type III protein export apparatus, which is postulated to be located on the cytoplasmic side of the flagellar basal body. The export specificity switching machinery, which consists of at least two proteins that function as a molecular ruler and an export switch, respectively, monitors the state of hook-basal body assembly in the cell exterior and switches export specificity, thereby coupling sequential flagellar gene expression with the flagellar assembly process. The export ATPase complex composed of an ATPase and its regulator acts as a pilot to deliver its export substrate to the export gate and helps initial entry of the substrate N-terminal chain into a narrow pore of the export gate. The energy of ATP hydrolysis appears to be used to disassemble and release the ATPase complex from the protein about to be exported, and the rest of the successive unfolding/translocation process of the long polypeptide chain is driven solely by proton motive force (PMF), perhaps through biased one-dimensional Brownian diffusion. Interestingly, the subunits of the ATPase complex have significant sequence similarities to subunits of F(0)F(1)-ATP synthase, a rotary motor that drives the chemical reaction of ATP synthesis using PMF, and the entire crystal structure of the export ATPase is extremely similar to the alpha/beta subunits of F(0)F(1)-ATP synthase, suggesting that the flagellar export apparatus and F(0)F(1)-ATP synthase share the mechanism for their two distinct functions.
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Affiliation(s)
- Tohru Minamino
- Graduate School of Frontier Biosciences, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan
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Brown JD, Saini S, Aldridge C, Herbert J, Rao CV, Aldridge PD. The rate of protein secretion dictates the temporal dynamics of flagellar gene expression. Mol Microbiol 2008; 70:924-37. [PMID: 18811728 DOI: 10.1111/j.1365-2958.2008.06455.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Flagellar gene expression is temporally regulated in response to the assembly state of the growing flagellum. The key mechanism for enforcing this temporal hierarchy in Salmonella enterica serovar Typhimurium is the sigma(28)-FlgM checkpoint, which couples the expression of the late flagellar (P(class3)) genes to the completion of the hook-basal body. This checkpoint is triggered when FlgM is secreted from the cell. In addition to the sigma(28)-FlgM checkpoint, a number of other regulatory mechanisms respond to the secretion of late proteins. In this work, we examined how middle (P(class2)) and late (P(class3)) gene expression is affected by late protein secretion. Dynamic analysis of flagellar gene expression identified a novel mechanism where induction of P(class2) activity is delayed either when late protein secretion is abolished or when late protein secretion is increased. Using a number of different approaches, we were able to show that this mechanism did not involve any known flagellar regulator. Furthermore, the changes in P(class2) activity were not correlated with the associated changes in P(class3) activity, which was found to be proportional to late protein secretion rates. Our data indicate that both P(class2) and P(class3) promoters are continuously regulated in response to assembly and late protein secretion rates. These results suggest that flagellar regulation is more complex than previously thought.
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Affiliation(s)
- Jonathon D Brown
- Centre for Bacterial Cell Biology, Newcastle University, Framlington Place, Newcastle upon Tyne, UK
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FliZ Is a posttranslational activator of FlhD4C2-dependent flagellar gene expression. J Bacteriol 2008; 190:4979-88. [PMID: 18469103 DOI: 10.1128/jb.01996-07] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
Flagellar assembly proceeds in a sequential manner, beginning at the base and concluding with the filament. A critical aspect of assembly is that gene expression is coupled to assembly. When cells transition from a nonflagellated to a flagellated state, gene expression is sequential, reflecting the manner in which the flagellum is made. A key mechanism for establishing this temporal hierarchy is the sigma(28)-FlgM checkpoint, which couples the expression of late flagellar (P(class3)) genes to the completion of the hook-basal body. In this work, we investigated the role of FliZ in coupling middle flagellar (P(class2)) gene expression to assembly in Salmonella enterica serovar Typhimurium. We demonstrate that FliZ is an FlhD(4)C(2)-dependent activator of P(class2)/middle gene expression. Our results suggest that FliZ regulates the concentration of FlhD(4)C(2) posttranslationally. We also demonstrate that FliZ functions independently of the flagellum-specific sigma factor sigma(28) and the filament-cap chaperone/FlhD(4)C(2) inhibitor FliT. Furthermore, we show that the previously described ability of sigma(28) to activate P(class2)/middle gene expression is, in fact, due to FliZ, as both are expressed from the same overlapping P(class2) and P(class3) promoters at the fliAZY locus. We conclude by discussing the role of FliZ regulation with respect to flagellar biosynthesis based on our characterization of gene expression and FliZ's role in swimming and swarming motility.
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Bresolin G, Trček J, Scherer S, Fuchs TM. Presence of a functional flagellar cluster Flag-2 and low-temperature expression of flagellar genes in Yersinia enterocolitica W22703. MICROBIOLOGY-SGM 2008; 154:196-206. [PMID: 18174138 DOI: 10.1099/mic.0.2007/008458-0] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Twelve Yersinia enterocolitica mutants carrying luxCDABE-transposon insertions in motility and chemotaxis genes were isolated on the basis of strong low-temperature induction. Two transposons were located within an 11.2 kb enteric flagellar cluster 2 (Flag-2) of Y. enterocolitica biotype 2, serotype O : 9 strain W22703. The Flag-2 gene cluster is absent from the corresponding genomic location of the sequenced strain Y. enterocolitica biotype 1B, serotype O : 8 strain 8081. Evidence for the functionality of the O : 9 Flag-2 genes, probably located within the plasticity zone of the genome, is provided by swarming assays. PCR analysis of 49 strains revealed the presence of Flag-2 genes in biotypes 2-5, but not in biotypes 1A or 1B. Bioluminescence, measured between 6 and 37 degrees C, showed that the expression of all genes located in Flag-2 and in the known flagellar cluster, Flag-1, was highest at approximately 20 degrees C, and that expression of two Flag-2 genes is FlhC-dependent. In a motility assay, a non-motile and a hyper-motile phenotype resulted from knockout mutations of the Flag-1 genes fliS1 and fliT, respectively. Complemented strains validated these results, confirming the regulatory role of FliT.
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Affiliation(s)
- Geraldine Bresolin
- Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Abteilung Mikrobiologie, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Janja Trček
- Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Abteilung Mikrobiologie, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Siegfried Scherer
- Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Abteilung Mikrobiologie, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
| | - Thilo M Fuchs
- Zentralinstitut für Ernährungs- und Lebensmittelforschung (ZIEL), Abteilung Mikrobiologie, Technische Universität München, Weihenstephaner Berg 3, 85354 Freising, Germany
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Cheung HY, Chan GKL, Cheung SH, Sun SQ, Fong WF. Morphological and chemical changes in the attached cells of Pseudomonas aeruginosa as primary biofilms develop on aluminium and CaF2 plates. J Appl Microbiol 2007; 102:701-10. [PMID: 17309619 DOI: 10.1111/j.1365-2672.2006.03137.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
AIMS To investigate the morphological and chemical changes in attached cells of Pseudomonas aeruginosa (ATCC 14886) at different stages of biofilm development on two different types of substrata. METHODS AND RESULTS The development of primary biofilm on aluminium plates representing metals and on CaF(2) discs representing dielectric materials was monitored by FTIR microscopy, ESEM, EDAX and protein analysis by SDS-PAGE. A unique cellular feature similar in morphology to pili was observed on the surface of P. aeruginosa adhering on aluminium but not on CaF(2). Results derived from FTIR analysis confirm on both substrata the successive importance of polysaccharides and proteins during the biofilm development. These results also revealed that the increase of the ratio of carboxylates to amide I was higher with the aluminium plates than with the CaF(2) discs. The number of cells adhered and the amount of oxygen incorporated in adhered cells on the latter materials were, respectively, less and almost nil in comparison with the former. Protein analysis of the lysates of cells by SDS-PAGE revealed that expression of one protein with a molecular weight of 45 kDa, was greatly enhanced in attached cells on both substrata. However, expression of another protein with molecular weight of 35 kDa was up-regulated only in cells adhering on CaF(2) but not in those on aluminium. CONCLUSION Depending on the nature of the surface, new proteinaceous complexes and cellular features were formed in the attachment process of P. aeruginosa. SIGNIFICANCE AND IMPACT OF THE STUDY The pattern of P. aeruginosa cells adhering onto CaF(2) discs and aluminium plates is different. Formation of biofilm is more difficult on CaF(2) than on aluminium.
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Affiliation(s)
- H-Y Cheung
- Department of Biology & Chemistry, City University of Hong Kong, Hong Kong SAR, China.
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Yamamoto S, Kutsukake K. FliT acts as an anti-FlhD2C2 factor in the transcriptional control of the flagellar regulon in Salmonella enterica serovar typhimurium. J Bacteriol 2006; 188:6703-8. [PMID: 16952964 PMCID: PMC1595477 DOI: 10.1128/jb.00799-06] [Citation(s) in RCA: 80] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Flagellar operons are divided into three classes with respect to their transcriptional hierarchy in Salmonella enterica serovar Typhimurium. The class 1 gene products FlhD and FlhC act together in an FlhD(2)C(2) heterotetramer, which binds upstream of the class 2 promoters to facilitate binding of RNA polymerase. Class 2 expression is known to be enhanced by a disruption mutation in a flagellar gene, fliT. In this study, we purified FliT protein in a His-tagged form and showed that the protein prevented binding of FlhD(2)C(2) to the class 2 promoter and inhibited FlhD(2)C(2)-dependent transcription. Pull-down and far-Western blotting analyses revealed that the FliT protein was capable of binding to FlhD(2)C(2) and FlhC and not to FlhD alone. We conclude that FliT acts as an anti-FlhD(2)C(2) factor, which binds to FlhD(2)C(2) through interaction with the FlhC subunit and inhibits its binding to the class 2 promoter.
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Affiliation(s)
- Shouji Yamamoto
- Department of Biology, Faculty of Science, Okayama University, Tsushima-Naka 3-1-1, Okayama 700-8530, Japan
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Titz B, Rajagopala SV, Ester C, Häuser R, Uetz P. Novel conserved assembly factor of the bacterial flagellum. J Bacteriol 2006; 188:7700-6. [PMID: 16936039 PMCID: PMC1636259 DOI: 10.1128/jb.00820-06] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
TP0658 (FliW) and its orthologs, conserved proteins of unknown function in Treponema pallidum and other species, interact with a C-terminal region of flagellin (FlaB1-3 in T. pallidum; FliC in most other species). Mutants of orthologs in Bacillus subtilis and Campylobacter jejuni (yviF, CJ1075) showed strongly reduced motility. TP0658 stabilizes flagellin in a way similar to FliS, suggesting that TP0658 is a conserved assembly factor for the bacterial flagellum.
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Affiliation(s)
- Björn Titz
- Institute of Genetics, Forschungszentrum Karlsruhe, Box 3640, D-76021 Karlsruhe, Germany
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Muskotál A, Király R, Sebestyén A, Gugolya Z, Végh BM, Vonderviszt F. Interaction of FliS flagellar chaperone with flagellin. FEBS Lett 2006; 580:3916-20. [PMID: 16806204 DOI: 10.1016/j.febslet.2006.06.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2006] [Accepted: 06/13/2006] [Indexed: 11/22/2022]
Abstract
Premature polymerization of flagellin (FliC), the main component of flagellar filaments, is prevented by the FliS chaperone in the cytosol. Interaction of FliS with flagellin was characterized by isothermal titration calorimetry producing an association constant of 1.9x10(7) M-1 and a binding stoichiometry of 1:1. Experiments with truncated FliC fragments demonstrated that the C-terminal disordered region of flagellin is essential for FliS binding. As revealed by thermal unfolding experiments, FliS does not function as an antifolding factor keeping flagellin in a secretion-competent conformation. Instead, FliS binding facilitates the formation of alpha-helical secondary structure in the chaperone binding region of flagellin.
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Affiliation(s)
- Adél Muskotál
- Department of Nanotechnology, Faculty of Information Technology, Pannon University, Egyetem u. 10, H-8200 Veszprém, Hungary
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Frye J, Karlinsey JE, Felise HR, Marzolf B, Dowidar N, McClelland M, Hughes KT. Identification of new flagellar genes of Salmonella enterica serovar Typhimurium. J Bacteriol 2006; 188:2233-43. [PMID: 16513753 PMCID: PMC1428135 DOI: 10.1128/jb.188.6.2233-2243.2006] [Citation(s) in RCA: 125] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
RNA levels of flagellar genes in eight different genetic backgrounds were compared to that of the wild type by DNA microarray analysis. Cluster analysis identified new, potential flagellar genes, three putative methyl-accepting chemotaxis proteins, STM3138 (McpA), STM3152 (McpB), and STM3216(McpC), and a CheV homolog, STM2314, in Salmonella, that are not found in Escherichia coli. Isolation and characterization of Mud-lac insertions in cheV, mcpB, mcpC, and the previously uncharacterized aer locus of S. enterica serovar Typhimurium revealed them to be controlled by sigma28-dependent flagellar class 3 promoters. In addition, the srfABC operon previously isolated as an SsrB-regulated operon clustered with the flagellar class 2 operon and was determined to be under FlhDC control. The previously unclassified fliB gene, encoding flagellin methylase, clustered as a class 2 gene, which was verified using reporter fusions, and the fliB transcriptional start site was identified by primer extension analysis. RNA levels of all flagellar genes were elevated in flgM or fliT null strains. RNA levels of class 3 flagellar genes were elevated in a fliS null strain, while deletion of the fliY, fliZ, or flk gene did not affect flagellar RNA levels relative to those of the wild type. The cafA (RNase G) and yhjH genes clustered with flagellar class 3 transcribed genes. Null alleles in cheV, mcpA, mcpB, mcpC, and srfB did not affect motility, while deletion of yhjH did result in reduced motility compared to that of the wild type.
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Affiliation(s)
- Jonathan Frye
- Sidney Kimmel Cancer Center, San Diego, California 92121, USA
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Macnab RM. Type III flagellar protein export and flagellar assembly. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2004; 1694:207-17. [PMID: 15546667 DOI: 10.1016/j.bbamcr.2004.04.005] [Citation(s) in RCA: 243] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2003] [Accepted: 04/29/2004] [Indexed: 10/26/2022]
Abstract
Bacterial flagella, unlike eukaryotic flagella, are largely external to the cell and therefore many of their subunits have to be exported. Export is ATP-driven. In Salmonella, the bacterium on which this chapter largely focuses, the apparatus responsible for flagellar protein export consists of six membrane components, three soluble components and several substrate-specific chaperones. Other flagellated eubacteria have similar systems. The membrane components of the export apparatus are housed within the flagellar basal body and deliver their substrates into a channel or lumen in the nascent structure from which point they diffuse to the far end and assemble. Both on the basis of sequence similarities of several components and structural similarities, the flagellar protein export systems clearly belong to the type III superfamily, whose other members are responsible for secretion of virulence factors by many species of pathogenic bacteria.
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Affiliation(s)
- Robert M Macnab
- Department of Molecular Biophysics and Biochemistry, Yale University, 0734, 266 Whitney Avenue, P.O. Box 208114, New Haven, CT 06520-8114, USA.
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