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1
Kanbe, Masaomi, Jin Yagasaki, Susanne Zehner, Michael Göttfert, and Shin-Ichi Aizawa. "Characterization of Two Sets of Subpolar Flagella in Bradyrhizobium japonicum." Journal of Bacteriology 189, no. 3 (November 10, 2006): 1083–89. http://dx.doi.org/10.1128/jb.01405-06.
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ABSTRACT Bradyrhizobium japonicum is one of the soil bacteria that form nodules on soybean roots. The cell has two sets of flagellar systems, one thick flagellum and a few thin flagella, uniquely growing at subpolar positions. The thick flagellum appears to be semicoiled in morphology, and the thin flagella were in a tight-curly form as observed by dark-field microscopy. Flagellin genes were identified from the amino acid sequence of each flagellin. Flagellar genes for the thick flagellum are scattered into several clusters on the genome, while those genes for the thin flagellum are compactly organized in one cluster. Both types of flagella are powered by proton-driven motors. The swimming propulsion is supplied mainly by the thick flagellum. B. japonicum flagellar systems resemble the polar-lateral flagellar systems of Vibrio species but differ in several aspects.
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Yen, Jiun Y., Katherine M. Broadway, and Birgit E. Scharf. "Minimum Requirements of Flagellation and Motility for Infection of Agrobacterium sp. Strain H13-3 by Flagellotropic Bacteriophage 7-7-1." Applied and Environmental Microbiology 78, no. 20 (August 3, 2012): 7216–22. http://dx.doi.org/10.1128/aem.01082-12.
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ABSTRACTThe flagellotropic phage 7-7-1 specifically adsorbs toAgrobacteriumsp. strain H13-3 (formerlyRhizobium lupiniH13-3) flagella for efficient host infection. TheAgrobacteriumsp. H13-3 flagellum is complex and consists of three flagellin proteins: the primary flagellin FlaA, which is essential for motility, and the secondary flagellins FlaB and FlaD, which have minor functions in motility. Using quantitative infectivity assays, we showed that absence of FlaD had no effect on phage infection, while absence of FlaB resulted in a 2.5-fold increase in infectivity. AflaAdeletion strain, which produces straight and severely truncated flagella, experienced a significantly reduced infectivity, similar to that of aflaB flaDstrain, which produces a low number of straight flagella. A strain lacking all three flagellin genes is phage resistant. In addition to flagellation, flagellar rotation is required for infection. A strain that is nonmotile due to an in-frame deletion in the gene encoding the motor component MotA is resistant to phage infection. We also generated two strains with point mutations in themotAgene resulting in replacement of the conserved charged residue Glu98, which is important for modulation of rotary speed. A change to the neutral Gln caused the flagellar motor to rotate at a constant high speed, allowing a 2.2-fold-enhanced infectivity. A change to the positively charged Lys caused a jiggly motility phenotype with very slow flagellar rotation, which significantly reduced the efficiency of infection. In conclusion, flagellar number and length, as well as speed of flagellar rotation, are important determinants for infection by phage 7-7-1.
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Wu, Cheng-Mu, Hsin-Hui Huang, Li-Hua Li, Yi-Tsung Lin, and Tsuey-Ching Yang. "Molecular Characterization of Three Tandemly Located Flagellin Genes of Stenotrophomonas maltophilia." International Journal of Molecular Sciences 23, no. 7 (March 31, 2022): 3863. http://dx.doi.org/10.3390/ijms23073863.
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Stenotrophomonas maltophilia is a motile, opportunistic pathogen. The flagellum, which is involved in swimming, swarming, adhesion, and biofilm formation, is considered a virulence factor for motile pathogens. Three flagellin genes, fliC1, fliC2, and fliC3, were identified from the sequenced S. maltophilia genome. FliC1, fliC2, and fliC3 formed an operon, and their encoding proteins shared 67–82% identity. Members of the fliC1C2C3 operon were deleted individually or in combination to generate single mutants, double mutants, and a triple mutant. The contributions of the three flagellins to swimming, swarming, flagellum morphology, adhesion, and biofilm formation were assessed. The single mutants generally had a compromise in swimming and no significant defects in swarming, adhesion on biotic surfaces, and biofilm formation on abiotic surfaces. The double mutants displayed obvious defects in swimming and adhesion on abiotic and biotic surfaces. The flagellin-null mutant lost swimming ability and was compromised in adhesion and biofilm formation. All tested mutants demonstrated substantial but different flagellar morphologies, supporting that flagellin composition affects filament morphology. Bacterial swimming motility was significantly compromised under an oxidative stress condition, irrespective of flagellin composition. Collectively, the utilization of these three flagellins for filament assembly equips S. maltophilia with flagella adapted to provide better ability in swimming, adhesion, and biofilm formation for its pathogenesis.
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Campodónico, Victoria L., Nicolás J. Llosa, Martha Grout, Gerd Döring, Tomás Maira-Litrán, and Gerald B. Pier. "Evaluation of Flagella and Flagellin of Pseudomonas aeruginosa as Vaccines." Infection and Immunity 78, no. 2 (December 7, 2009): 746–55. http://dx.doi.org/10.1128/iai.00806-09.
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ABSTRACT Pseudomonas aeruginosa is a serious pathogen in hospitalized, immunocompromised, and cystic fibrosis (CF) patients. P. aeruginosa is motile via a single polar flagellum made of polymerized flagellin proteins differentiated into two major serotypes: a and b. Antibodies to flagella delay onset of infection in CF patients, but whether immunity to polymeric flagella and that to monomeric flagellin are comparable has not been addressed, nor has the question of whether such antibodies might negatively impact Toll-like receptor 5 (TLR5) activation, an important component of innate immunity to P. aeruginosa. We compared immunization with flagella and that with flagellin for in vitro effects on motility, opsonic killing, and protective efficacy using a mouse pneumonia model. Antibodies to flagella were superior to antibodies to flagellin at inhibiting motility, promoting opsonic killing, and mediating protection against P. aeruginosa pneumonia in mice. Protection against the flagellar type strains PAK and PA01 was maximal, but it was only marginal against motile clinical isolates from flagellum-immunized CF patients who nonetheless became colonized with P. aeruginosa. Purified flagellin was a more potent activator of TLR5 than were flagella and also elicited higher TLR5-neutralizing antibodies than did immunization with flagella. Antibody to type a but not type b flagella or flagellin inhibited TLR5 activation by whole bacterial cells. Overall, intact flagella appear to be superior for generating immunity to P. aeruginosa, and flagellin monomers might induce antibodies capable of neutralizing innate immunity due to TLR5 activation, but solid immunity to P. aeruginosa based on flagellar antigens may require additional components beyond type a and type b proteins from prototype strains.
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Li, Chunhao, Melanie Sal, Michael Marko, and Nyles W. Charon. "Differential Regulation of the Multiple Flagellins in Spirochetes." Journal of Bacteriology 192, no. 10 (March 19, 2010): 2596–603. http://dx.doi.org/10.1128/jb.01502-09.
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ABSTRACT The expression of flagellin genes in most bacteria is typically regulated by the flagellum-specific sigma28 factor FliA, and an anti-sigma28 factor, FlgM. However, the regulatory hierarchy in several bacteria that have multiple flagellins is more complex. In these bacteria, the flagellin genes are often transcribed by at least two different sigma factors. The flagellar filament in spirochetes consists of one to three FlaB core proteins and at least one FlaA sheath protein. Here, the genetically amenable bacterium Brachyspira hyodysenteriae was used as a model spirochete to investigate the regulation of its four flagellin genes, flaA, flaB1, flaB2, and flaB3. We found that the flaB1 and flaB2 genes are regulated by sigma28, whereas the flaA and flaB3 genes are controlled by sigma70. The analysis of a flagellar motor switch fliG mutant further supported this proposition; in the mutant, the transcription of flaB1 and flaB2 was inhibited, but that of flaA and flaB3 was not. In addition, the continued expression of flaA and flaB3 in the mutant resulted in the formation of incomplete flagellar filaments that were hollow tubes and consisted primarily of FlaA. Finally, our recent studies have shown that each flagellin unit contributes to the stiffness of the periplasmic flagella, and this stiffness directly correlates with motility. The regulatory mechanism identified here should allow spirochetes to change the relative ratio of these flagellin proteins and, concomitantly, vary the stiffness of their flagellar filament.
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Alexandre, Gladys, René Rohr, and René Bally. "A Phase Variant of Azospirillum lipoferum Lacks a Polar Flagellum and Constitutively Expresses Mechanosensing Lateral Flagella." Applied and Environmental Microbiology 65, no. 10 (October 1, 1999): 4701–4. http://dx.doi.org/10.1128/aem.65.10.4701-4704.1999.
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ABSTRACT Flagellation of a nonswimming variant of the mixed flagellated bacterium Azospirillum lipoferum 4B was characterized by electron microscopy, and polyclonal antibodies were raised against polar and lateral flagellins. The variant cells lacked a polar flagellum due to a defect in flagellin synthesis and constitutively expressed lateral flagella. The variant cells were able to respond to conditions that restricted the rotation of lateral flagella by producing more lateral flagella, suggesting that the lateral flagella, as well as the polar flagellum, are mechanosensing.
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Rabaan, Ali A., Ioannis Gryllos, Juan M. Tomás, and Jonathan G. Shaw. "Motility and the Polar Flagellum Are Required for Aeromonas caviae Adherence to HEp-2 Cells." Infection and Immunity 69, no. 7 (July 1, 2001): 4257–67. http://dx.doi.org/10.1128/iai.69.7.4257-4267.2001.
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ABSTRACT Aeromonas caviae is increasingly being recognized as a cause of gastroenteritis, especially among the young. The adherence of aeromonads to human epithelial cells in vitro has been correlated with enteropathogenicity, but the mechanism is far from well understood. Initial investigations demonstrated that adherence of A. caviae to HEp-2 cells was significantly reduced by either pretreating bacterial cells with an antipolar flagellin antibody or by pretreating HEp-2 cells with partially purified flagella. To precisely define the role of the polar flagellum in aeromonad adherence, we isolated the A. caviae polar flagellin locus and identified five polar flagellar genes, in the order flaA, flaB, flaG, flaH, and flaJ. Each gene was inactivated using a kanamycin resistance cartridge that ensures the transcription of downstream genes, and the resulting mutants were tested for motility, flagellin expression, and adherence to HEp-2 cells. N-terminal amino acid sequencing, mutant analysis, and Western blotting demonstrated that A. caviae has a complex flagellum filament composed of two flagellin subunits encoded by flaAand flaB. The predicted molecular mass of both flagellins was ∼31,700 Da; however, their molecular mass estimated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis was ∼35,500 Da. This aberrant migration was thought to be due to their glycosylation, since the proteins were reactive in glycosyl group detection assays. Single mutations in either flaA orflaB did not result in loss of flagella but did result in decreased motility and adherence by approximately 50%. Mutation offlaH, flaJ, or both flagellin genes resulted in the complete loss of motility, flagellin expression, and adherence. However, mutation of flaG did not affect motility but did significantly reduce the level of adherence. Centrifugation of the flagellate mutants (flaA, flaB, and flaG) onto the cell monolayers did not increase adherence, whereas centrifugation of the aflagellate mutants (flaH, flaJ, and flaA flaB) increased adherence slightly. We conclude that maximum adherence of A. caviae to human epithelial cells in vitro requires motility and optimal flagellar function.
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Fedorov, Oleg V., Michael G. Pyatibratov, Alla S. Kostyukova, Natalja K. Osina, and Valery Yu Tarasov. "Protofilament as a structural element of flagella of haloalkalophilic archaebacteria." Canadian Journal of Microbiology 40, no. 1 (January 1, 1994): 45–53. http://dx.doi.org/10.1139/m94-007.
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Flagella of the haloalkalophilic archaebacterium Natronobacterium magadii were purified and characterized. The diameter of the flagella was 10 nm. It was shown that the flagella consist of four major proteins with molecular weights of 105 000, 60 000, 59 000, and 45 000. With decreasing NaCl concentration, the flagella dissociated into protofilaments. The structure of dissociated flagella and individual flagellins was studied by limited proteolysis. It was found that proteolytic cleavage of flagellins in dissociated flagella into high molecular weight fragments (about 40 000) did not lead to protofilament degradation. It was shown that the most stable fragment is formed from the 60 000 molecular weight flagellin. Cleavage of this fragment led to complete disappearance of protofilaments. On the basis of the data obtained, possible principles of archaebacterial flagellar construction are discussed.Key words: flagellin, archaebacteria, protofilaments, Natronobacterium magadii.
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Rementeria, A., A. B. Vivanco, A. Ramirez, F. L. Hernando, J. Bikandi, S. Herrera-León, A. Echeita, and J. Garaizar. "Characterization of a Monoclonal Antibody Directed against Salmonella enterica Serovar Typhimurium and Serovar [4,5,12:i:−]." Applied and Environmental Microbiology 75, no. 5 (January 5, 2009): 1345–54. http://dx.doi.org/10.1128/aem.01597-08.
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ABSTRACT Flagellar extracts of Salmonella enterica serovars expressing phase 2 H1 antigenic complex (H:1,2, H:1,5, H:1,6, and H:1,7) and a mutant flagellin obtained by site-directed mutagenesis of the fljB gene from serovar Typhimurium at codon 218, transforming threonine to alanine, expressed in Escherichia coli (fljB218 A ) were used to analyze the H1 antigenic complex. Cross-reactions were detected by Western blotting and dot blotting using commercial polyclonal antibodies against the different wild-type extracts and mutant FljB218A. Therefore, we produced a monoclonal antibody (MAb), 23D4, isotyped as immunoglobulin M, against H:1,2 S. enterica serovar Typhimurium flagellin. The mutant flagellin was not recognized by this MAb. When a large number of phase 1 and phase 2 flagellin antigens of different serovars were used to characterize the 23D4 MAb, only extracts of serovars Typhimurium and [4,5,12:i:−] reacted. The protein composition of phase 1 and phase 2 extracts and highly purified H:1,2 flagellin from serovar Typhimurium strain LT2 and extract of strain 286 (serovar [4,5,12:i:−]), which reacted with the MAb, was studied. Phase 2 flagellin (FljBH:1,2) was detected in phase 1 and phase 2 flagellar heat extracts of serovar Typhimurium and was the single protein identified in all spots of purified H:1,2 flagellin. FliC, FlgK, and other proteins were detected in some immunoreactive spots and in the flagellar extract of serovar [4,5,12:i:−]. Immunoelectron microscopy of complete bacteria with 23D4 showed MAb attachment at the base of flagella, although the MAb failed to recognize the filament of flagella. Nevertheless, the results obtained by the other immunological tests (enzyme-linked immunosorbent assay, Western blotting, and dot blotting) indicate a reaction against flagellins. The epitopes could also be shared by other proteins on spots where FljB is not present, such as aminopeptidase B, isocitrate lyase, InvE, EF-TuA, enolase, DnaK, and others. In conclusion, MAb 23D4 can be useful for detection and diagnostic purposes of S. enterica serovar Typhimurium and serovar [4,5,12:i:−] and could be also helpful for epitope characterization of flagellum-associated antigens.
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Mangan, Erin K., Jaleh Malakooti, Anthony Caballero, Paul Anderson, Bert Ely, and James W. Gober. "FlbT Couples Flagellum Assembly to Gene Expression in Caulobacter crescentus." Journal of Bacteriology 181, no. 19 (October 1, 1999): 6160–70. http://dx.doi.org/10.1128/jb.181.19.6160-6170.1999.
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ABSTRACT The biogenesis of the polar flagellum of Caulobacter crescentus is regulated by the cell cycle as well as by atrans-acting regulatory hierarchy that functions to couple flagellum assembly to gene expression. The assembly of early flagellar structures (MS ring, switch, and flagellum-specific secretory system) is required for the transcription of class III genes, which encode the remainder of the basal body and the external hook structure. Similarly, the assembly of class III gene-encoded structures is required for the expression of the class IV flagellins, which are incorporated into the flagellar filament. Here, we demonstrate that mutations inflbT, a flagellar gene of unknown function, can restore flagellin protein synthesis and the expression offljK::lacZ (25-kDa flagellin) protein fusions in class III flagellar mutants. These results suggest that FlbT functions to negatively regulate flagellin expression in the absence of flagellum assembly. Deletion analysis shows that sequences within the 5′ untranslated region of the fljK transcript are sufficient for FlbT regulation. To determine the mechanism of FlbT-mediated regulation, we assayed the stability of fljKmRNA. The half-life (t 1/2) of fljKmRNA in wild-type cells was approximately 11 min and was reduced to less than 1.5 min in a flgE (hook) mutant. A flgE flbT double mutant exhibited an mRNA t 1/2of greater than 30 min. This suggests that the primary effect of FlbT regulation is an increased turnover of flagellin mRNA. The increasedt 1/2 of fljK mRNA in aflbT mutant has consequences for the temporal expression offljK. In contrast to the case for wild-type cells,fljK::lacZ protein fusions in the mutant are expressed almost continuously throughout the C. crescentus cell cycle, suggesting that coupling of flagellin gene expression to assembly has a critical influence on regulating cell cycle expression.
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Bardy, Sonia L., Takahisa Mori, Kaoru Komoriya, Shin-Ichi Aizawa, and Ken F. Jarrell. "Identification and Localization of Flagellins FlaA and FlaB3 within Flagella of Methanococcus voltae." Journal of Bacteriology 184, no. 19 (October 1, 2002): 5223–33. http://dx.doi.org/10.1128/jb.184.19.5223-5233.2002.
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ABSTRACT Methanococcus voltae possesses four flagellin genes, two of which (flaB1 and flaB2) have previously been reported to encode major components of the flagellar filament. The remaining two flagellin genes, flaA and flaB3, are transcribed at lower levels, and the corresponding proteins remained undetected prior to this work. Electron microscopy examination of flagella isolated by detergent extraction of whole cells revealed a curved, hook-like region of varying length at the end of a long filament. Enrichment of the curved region of the flagella resulted in the identification of FlaB3 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and N-terminal sequencing, and the localization of this flagellin to the cell-proximal portion of the flagellum was confirmed through immunoblotting and immunoelectron microscopy with FlaB3-specific antibodies, indicating that FlaB3 likely composes the curved portion of the flagella. This could represent a unique case of a flagellin performing the role of the bacterial hook protein. FlaA-specific antibodies were used in immunoblotting to determine that FlaA is found throughout the flagellar filament. M. voltae cells were transformed with a modified flaA gene containing a hemagglutinin (HA) tag introduced into the variable region. Transformants that had replaced the wild-type copy of the flaA gene with the HA-tagged version incorporated the HA-tagged version of FlaA into flagella which appeared normal by electron microscopy.
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Marathe, Sandhya Amol, Arjun Balakrishnan, Vidya Devi Negi, Deepika Sakorey, Nagasuma Chandra, and Dipshikha Chakravortty. "Curcumin Reduces the Motility of Salmonella enterica Serovar Typhimurium by Binding to the Flagella, Thereby Leading to Flagellar Fragility and Shedding." Journal of Bacteriology 198, no. 13 (April 18, 2016): 1798–811. http://dx.doi.org/10.1128/jb.00092-16.
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ABSTRACTOne of the important virulence properties of the pathogen is its ability to travel to a favorable environment, cross the viscous mucus barrier (intestinal barrier for enteric pathogens), and reach the epithelia to initiate pathogenesis with the help of an appendage, like flagella. Nonetheless, flagella can act as an “Achilles heel,” revealing the pathogen's presence to the host through the stimulation of innate and adaptive immune responses. We assessed whether curcumin, a dietary polyphenol, could alter the motility ofSalmonella, a foodborne pathogen. It reduced the motility ofSalmonella entericaserovar Typhimurium by shortening the length of the flagellar filament (from ∼8 μm to ∼5 μm) and decreasing its density (4 or 5 flagella/bacterium instead of 8 or 9 flagella/bacterium). Upon curcumin treatment, the percentage of flagellated bacteria declined from ∼84% to 59%. However, no change was detected in the expression of the flagellin gene and protein. A fluorescence binding assay demonstrated binding of curcumin to the flagellar filament. This might make the filament fragile, breaking it into smaller fragments. Computational analysis predicted the binding of curcumin, its analogues, and its degraded products to a flagellin molecule at an interface between domains D1 and D2. Site-directed mutagenesis and a fluorescence binding assay confirmed the binding of curcumin to flagellin at residues ASN120, ASP123, ASN163, SER164, ASN173, and GLN175.IMPORTANCEThis work, to our knowledge the first report of its kind, examines how curcumin targets flagellar density and affects the pathogenesis of bacteria. We found that curcumin does not affect any of the flagellar synthesis genes. Instead, it binds to the flagellum and makes it fragile. It increases the torsional stress on the flagellar filament that then breaks, leaving fewer flagella around the bacteria. Flagella, which are crucial ligands for Toll-like receptor 5, are some of the most important appendages ofSalmonella. Curcumin is an important component of turmeric, which is a major spice used in Asian cooking. The loss of flagella can, in turn, change the pathogenesis of bacteria, making them more robust and fit in the host.
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Naito, Kana, Fumiko Taguchi, Tomoko Suzuki, Yoshishige Inagaki, Kazuhiro Toyoda, Tomonori Shiraishi, and Yuki Ichinose. "Amino Acid Sequence of Bacterial Microbe-Associated Molecular Pattern flg22 Is Required for Virulence." Molecular Plant-Microbe Interactions® 21, no. 9 (September 2008): 1165–74. http://dx.doi.org/10.1094/mpmi-21-9-1165.
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Flagellin proteins derived from Pseudomonas syringae pv. tabaci 6605 and flg22Pa (QRLSTGSRINSAKDDAAGLQIA), one of the microbe-associated molecular patterns (MAMP) in bacterial flagellin, induce cell death and growth inhibition in Arabidopsis thaliana. To examine the importance of aspartic acid (D) at position 43 from the N-terminus of a flagellin in its elicitor activity, D43 was replaced with valine (V) and alanine (A) in P. syringae pv. tabaci flagellin and flg22Pta. The abilities of flagellins from P. syringae pv. tabaci D43V and D43A to induce cell death and growth inhibition were reduced, whereas the abilities of flg22PtaD43V and flg22PtaD43A were abolished. These results indicate that D43 is important for elicitor activity in P. syringae pv. tabaci. When tobacco plants were inoculated with each bacterium by the spray method, both P. syringae pv. tabaci D43V and D43A mutants had remarkably reduced ability to cause disease symptoms. Both mutants had reduced or no swimming and swarming motilities and adhesion ability. In P. syringae pv. tabaci D43V, little flagellin protein was detected and few flagella were observed by electron microscopy. These results indicate that mutant flagella are unstable and that flagellar motility is impaired. Thus, the amino acid residue required for MAMP activity is important for the intrinsic flagellar function.
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Verma, Amrisha, Shiwani K. Arora, Sudha K. Kuravi, and Reuben Ramphal. "Roles of Specific Amino Acids in the N Terminus of Pseudomonas aeruginosa Flagellin and of Flagellin Glycosylation in the Innate Immune Response." Infection and Immunity 73, no. 12 (December 2005): 8237–46. http://dx.doi.org/10.1128/iai.73.12.8237-8246.2005.
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ABSTRACT The Toll-like receptor 5 (TLR5) binding site has been predicted to be in the N terminus of the flagellin molecule. In order to better define the interaction between the N-terminal amino acids of Pseudomonas aeruginosa flagellin and TLR5, site-specific mutations were generated between residues 88 and 97 of P. aeruginosa PAK flagellin as well as outside of this region. The mutant flagellins were expressed in Escherichia coli BL21(plysS), purified by affinity chromatography, and passed through a polymyxin B column to remove contaminating lipopolysaccharide (LPS). Their ability to stimulate interleukin-8 (IL-8) release from A549 cells was examined. The cloned mutated genes were used to complement a PAK fliC mutant in order to test for effects on motility and on IL-8 release by purified flagellar preparations. All the mutations, single or double, in the predicted TLR5 binding region reduced IL-8 signaling to less than 95% of the wild-type flagellin levels, but the single mutation outside the binding region had no effect. Changes made at two amino acid sites resulted in loss/reduction of motility; however, changes made at single sites, i.e., Q83A, L88A, R90A, M91A, L94A, and Q97A, had no effect on motility. The mutated genes encoding two of the motile but poorly signaling flagellins had no compensatory mutations to allow motility. Thus, while it is speculated that pathogen-associated molecular patterns (PAMPs) have evolved in locations that are essential to maintain function, it appears that there is tolerance for at least single amino acid changes in the PAMP of P. aeruginosa flagellin. The purpose of flagellin glycosylation in P. aeruginosa is unknown. In order to examine its role, if any, in signaling an inflammatory response, we used whole flagella from the motile chromosomal mutant strains PAKrfbC and PAO1rfbC, which are defective in flagellin glycosylation. IL-8 release from A549 cells stimulated with nonglycosylated flagellar preparations (having less then 1 picogram of LPS/μg) was significantly reduced compared to their respective wild-type flagellar preparations, indicating a role of flagellar glycosylation in the proinflammatory action of Pseudomonas flagellin. The basis of the latter activity is unknown, since the glycosylation sites are found in the D3 domain of flagellins and the TLR5 binding site is located in the D1 domain. Thus, P. aeruginosa flagellin has evolved additional flagellar signaling mechanisms over that described for Salmonella flagellin.
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Yoon, Sang Sun, and John J. Mekalanos. "Decreased Potency of the Vibrio cholerae Sheathed Flagellum To Trigger Host Innate Immunity." Infection and Immunity 76, no. 3 (January 3, 2008): 1282–88. http://dx.doi.org/10.1128/iai.00736-07.
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ABSTRACT Vibrio cholerae is a monoflagellated gram-negative bacterium that causes the severe diarrheal disease cholera. In contrast to Salmonella enterica serovar Typhimurium infection, which is accompanied by both acute diarrhea and high-level inflammation, V. cholerae infection is largely noninflammatory in human hosts. Bacterial flagella are composed of flagellin, a highly conserved protein that is also a target of the innate immune response. Because the V. cholerae flagellum is covered by a sheath, we hypothesized that it might be less prone to activation of the innate immune response than nonsheathed flagella, such as those produced by Salmonella serovar Typhimurium. Indeed, compared with Salmonella serovar Typhimurium flagella, V. cholerae flagella demonstrated significantly reduced NF-κB activation in A549 human pulmonary epithelial cells. However, V. cholerae flagellin monomers, FlaD and FlaC, were almost equally potent with purified FliC, a monomer derived from Salmonella serovar Typhimurium flagella, in NF-κB activation. Heat- and acid-induced dissociation assays showed that Salmonella serovar Typhimurium flagella disassembled far more readily into monomeric flagellins than V. cholerae flagella, suggesting that the differential levels of NF-κB activation by V. cholerae and Salmonella serovar Typhimurium flagella are likely attributable to the difference in their flagellin shedding. Our results suggest that monomer dissociation of V. cholerae flagella is suppressed likely due to the presence of the sheath and that this unique structural feature of V. cholerae flagella may have evolved as a strategy to evade flagellin-triggered host innate immune responses in various host species.
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Wang, Hongou, Zhiheng Tang, Baoshuai Xue, Qinghui Lu, Xiaoyun Liu, and Qinghua Zou. "Salmonella Regulator STM0347 Mediates Flagellar Phase Variation via Hin Invertase." International Journal of Molecular Sciences 23, no. 15 (July 30, 2022): 8481. http://dx.doi.org/10.3390/ijms23158481.
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Salmonella enterica is one of the most important food-borne pathogens, whose motility and virulence are highly related to flagella. Flagella alternatively express two kinds of surface antigen flagellin, FliC and FljB, in a phenomenon known as flagellar phase variation. The molecular mechanisms by which the switching orientation of the Hin-composed DNA segment mediates the expression of the fljBA promoter have been thoroughly illustrated. However, the precise regulators that control DNA strand exchange are barely understood. In this study, we found that a putative response regulator, STM0347, contributed to the phase variation of flagellin in S. Typhimurium. With quantitative proteomics and secretome profiling, a lack of STM0347 was confirmed to induce the transformation of flagellin from FliC to FljB. Real-time PCR and in vitro incubation of SMT0347 with the hin DNA segment suggested that STM0347 disturbed Hin-catalyzed DNA reversion via hin degradation, and the overexpression of Hin was sufficient to elicit flagellin variation. Subsequently, the Δstm0347 strain was outcompeted by its parental strain in HeLa cell invasion. Collectively, our results reveal the crucial role of STM0347 in Salmonella virulence and flagellar phase variation and highlight the complexity of the regulatory network of Hin-modulated flagellum phase variation in Salmonella.
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Klose, Karl E., and John J. Mekalanos. "Differential Regulation of Multiple Flagellins inVibrio cholerae." Journal of Bacteriology 180, no. 2 (January 15, 1998): 303–16. http://dx.doi.org/10.1128/jb.180.2.303-316.1998.
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ABSTRACT Vibrio cholerae, the causative agent of the human diarrheal disease cholera, is a motile bacterium with a single polar flagellum. Motility has been implicated as a virulence determinant in some animal models of cholera, but the relationship between motility and virulence has not yet been clearly defined. We have begun to define the regulatory circuitry controlling motility. We have identified fiveV. cholerae flagellin genes, arranged in two chromosomal loci, flaAC and flaEDB; all five genes have their own promoters. The predicted gene products have a high degree of homology to each other. A strain containing a single mutation inflaA is nonmotile and lacks a flagellum, while strains containing multiple mutations in the other four flagellin genes, including a flaCEDB strain, remain motile. Measurement offla promoter-lacZ fusions reveals that all five flagellin promoters are transcribed at high levels in both wild-type and flaA strains. Measurement of the flagellin promoter-lacZ fusions in Salmonella typhimuriumindicates that the promoter for flaA is transcribed by the ς54 holoenzyme form of RNA polymerase while theflaE, flaD, and flaB promoters are transcribed by the ς28 holoenzyme. These results reveal that the V. cholerae flagellum is a complex structure with multiple flagellin subunits including FlaA, which is essential for flagellar synthesis and is differentially regulated from the other flagellins.
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Tanskanen, Jarna, Timo K. Korhonen, and Benita Westerlund-Wikstr�m. "Construction of a Multihybrid Display System: Flagellar Filaments Carrying Two Foreign Adhesive Peptides." Applied and Environmental Microbiology 66, no. 9 (September 1, 2000): 4152–56. http://dx.doi.org/10.1128/aem.66.9.4152-4156.2000.
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ABSTRACT A multivalent, bifunctional flagellum carrying two different adhesive peptides in separate flagellin subunits within a filament was constructed in Escherichia coli. The inserted peptides were the fibronectin-binding 115-mer D repeat region of Staphylococcus aureus and the 302-mer collagen-binding region of YadA ofYersinia enterocolitica. Western blotting, immunoelectron microscopy, and adhesion tests with hybrid flagella from an intrans-complemented ΔfliC E. coli strain showed that individual filaments consisted of both recombinant flagellins.
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Logan, Susan M. "Flagellar glycosylation – a new component of the motility repertoire?" Microbiology 152, no. 5 (May 1, 2006): 1249–62. http://dx.doi.org/10.1099/mic.0.28735-0.
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The biosynthesis, assembly and regulation of the flagellar apparatus has been the subject of extensive studies over many decades, with considerable attention devoted to the peritrichous flagella of Escherichia coli and Salmonella enterica. The characterization of flagellar systems from many other bacterial species has revealed subtle yet distinct differences in composition, regulation and mode of assembly of this important subcellular structure. Glycosylation of the major structural protein, the flagellin, has been shown most recently to be an important component of numerous flagellar systems in both Archaea and Bacteria, playing either an integral role in assembly or for a number of bacterial pathogens a role in virulence. This review focuses on the structural diversity in flagellar glycosylation systems and demonstrates that as a consequence of the unique assembly processes, the type of glycosidic linkage found on archaeal and bacterial flagellins is distinctive.
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Millikan, Deborah S., and Edward G. Ruby. "Vibrio fischeri Flagellin A Is Essential for Normal Motility and for Symbiotic Competence during Initial Squid Light Organ Colonization." Journal of Bacteriology 186, no. 13 (July 1, 2004): 4315–25. http://dx.doi.org/10.1128/jb.186.13.4315-4325.2004.
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ABSTRACT The motile bacterium Vibrio fischeri is the specific bacterial symbiont of the Hawaiian squid Euprymna scolopes. Because motility is essential for initiating colonization, we have begun to identify stage-specific motility requirements by creating flagellar mutants that have symbiotic defects. V. fischeri has six flagellin genes that are uniquely arranged in two chromosomal loci, flaABCDE and flaF. With the exception of the flaA product, the predicted gene products are more similar to each other than to flagellins of other Vibrio species. Immunoblot analysis indicated that only five of the six predicted proteins were present in purified flagella, suggesting that one protein, FlaF, is unique with respect to either its regulation or its function. We created mutations in two genes, flaA and flaC. Compared to a flaC mutant, which has wild-type flagellation, a strain having a mutation in the flaA gene has fewer flagella per cell and exhibits a 60% decrease in its rate of migration in soft agar. During induction of light organ symbiosis, colonization by the flaA mutant is impaired, and this mutant is severely outcompeted when it is presented to the animal as a mixed inoculum with the wild-type strain. Furthermore, flaA mutant cells are preferentially expelled from the animal, suggesting either that FlaA plays a role in adhesion or that normal motility is an advantage for retention within the host. Taken together, these results show that the flagellum of V. fischeri is a complex structure consisting of multiple flagellin subunits, including FlaA, which is essential both for normal flagellation and for motility, as well as for effective symbiotic colonization.
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Garrido-Sanz, Daniel, Miguel Redondo-Nieto, Elías Mongiardini, Esther Blanco-Romero, David Durán, Juan Quelas, Marta Martin, Rafael Rivilla, Aníbal Lodeiro, and M. Althabegoiti. "Phylogenomic Analyses of Bradyrhizobium Reveal Uneven Distribution of the Lateral and Subpolar Flagellar Systems, Which Extends to Rhizobiales." Microorganisms 7, no. 2 (February 13, 2019): 50. http://dx.doi.org/10.3390/microorganisms7020050.
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Dual flagellar systems have been described in several bacterial genera, but the extent of their prevalence has not been fully explored. Bradyrhizobium diazoefficiens USDA 110T possesses two flagellar systems, the subpolar and the lateral flagella. The lateral flagellum of Bradyrhizobium displays no obvious role, since its performance is explained by cooperation with the subpolar flagellum. In contrast, the lateral flagellum is the only type of flagella present in the related Rhizobiaceae family. In this work, we have analyzed the phylogeny of the Bradyrhizobium genus by means of Genome-to-Genome Blast Distance Phylogeny (GBDP) and Average Nucleotide Identity (ANI) comparisons of 128 genomes and divided it into 13 phylogenomic groups. While all the Bradyrhizobium genomes encode the subpolar flagellum, none of them encodes only the lateral flagellum. The simultaneous presence of both flagella is exclusive of the B. japonicum phylogenomic group. Additionally, 292 Rhizobiales order genomes were analyzed and both flagellar systems are present together in only nine genera. Phylogenetic analysis of 150 representative Rhizobiales genomes revealed an uneven distribution of these flagellar systems. While genomes within and close to the Rhizobiaceae family only possess the lateral flagellum, the subpolar flagellum is exclusive of more early-diverging families, where certain genera also present both flagella.
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Iino, T., Tomoko Oguchi, and T. Kuroiwa. "Polymorphism in a Flagellar-shape Mutant of Salmonella typhimurium." Microbiology 81, no. 1 (January 1, 2000): 37–45. http://dx.doi.org/10.1099/00221287-81-1-37.
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A flagellar-shape mutant, designated ‘polymorphous’, was isolated from a normal flagella strain of Salmonella typhimurium. The mutant produces normal flagella in phase 1 and polymorphous flagella in phase 2. The polymorphous flagella are either straight or possess one of the four distinct wave-forms, namely M, S, N or C, when observed with an electron microscope after negative staining with phosphotungstic acid or uranyl acetate. Conversions between the four wave-forms were found to be brought about mainly by a change in the degree of twisting of longitudinal strands around the axis of a flagella filament, without marked change in the relative lengths of the outermost and innermost strands. The major fraction of the polymorphous mutant flagella showed the N-form under any conditions of specimen preparation. The remaining four forms appeared as minor fractions in various proportions. Specimens fixed with formalin showed less pronounced polymorphism than unfixed ones. Negative staining with uranyl acetate was more effective than with phosphotungstic acid for observing polymorphism. Even though more than one form appeared among the polymorphous flagella, each individual flagellum comprised a single form except for a rare coexistence of S and N. The same form of flagella tended to coexist in a bacterium in a heteromorphously flagellated cell population. It was concluded that the conformation and arrangement of the flagellin molecules responsible for wave-form result from strong mutual interactions between the neighbouring molecules along the flagellar filaments and also, to a lesser extent, between the neighbouring filaments in a flagellar bundle, as well as being influenced by the physico-chemical environment.
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Ely, Bert, Tracey W. Ely, William B. Crymes, and Scott A. Minnich. "A Family of Six Flagellin Genes Contributes to the Caulobacter crescentus Flagellar Filament." Journal of Bacteriology 182, no. 17 (September 1, 2000): 5001–4. http://dx.doi.org/10.1128/jb.182.17.5001-5004.2000.
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ABSTRACT The Caulobacter crescentus flagellar filament is assembled from multiple flagellin proteins that are encoded by six genes. The amino acid sequences of the FljJ and FljL flagellins are divergent from those of the other four flagellins. Since these flagellins are the first to be assembled in the flagellar filament, one or both might have specialized to facilitate the initiation of filament assembly.
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Filip’echeva, Yulia A., Andrei V. Shelud’ko, Alexei G. Prilipov, Gennady L. Burygin, Elizaveta M. Telesheva, Stella S. Yevstigneyeva, Marina P. Chernyshova, Lilia P. Petrova, and Elena I. Katsy. "Plasmid AZOBR_p1-borne fabG gene for putative 3-oxoacyl-[acyl-carrier protein] reductase is essential for proper assembly and work of the dual flagellar system in the alphaproteobacterium Azospirillum brasilense Sp245." Canadian Journal of Microbiology 64, no. 2 (February 2018): 107–18. http://dx.doi.org/10.1139/cjm-2017-0561.
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Azospirillum brasilense can swim and swarm owing to the activity of a constitutive polar flagellum (Fla) and inducible lateral flagella (Laf), respectively. Experimental data on the regulation of the Fla and Laf assembly in azospirilla are scarce. Here, the coding sequence (CDS) AZOBR_p1160043 (fabG1) for a putative 3-oxoacyl-[acyl-carrier protein (ACP)] reductase was found essential for the construction of both types of flagella. In an immotile leaky Fla− Laf− fabG1::Omegon-Km mutant, Sp245.1610, defects in flagellation and motility were fully complemented by expressing the CDS AZOBR_p1160043 from plasmid pRK415. When pRK415 with the cloned CDS AZOBR_p1160045 (fliC) for a putative 65.2 kDa Sp245 Fla flagellin was transferred into the Sp245.1610 cells, the bacteria also became able to assemble a motile single flagellum. Some cells, however, had unusual swimming behavior, probably because of the side location of the organelle. Although the assembly of Laf was not restored in Sp245.1610 (pRK415-p1160045), this strain was somewhat capable of swarming motility. We propose that the putative 3-oxoacyl-[ACP] reductase encoded by the CDS AZOBR_p1160043 plays a role in correct flagellar location in the cell envelope and (or) in flagellar modification(s), which are also required for the inducible construction of Laf and for proper swimming and swarming motility of A. brasilense Sp245.
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Zhuang, Xiang-Yu, and Chien-Jung Lo. "Construction and Loss of Bacterial Flagellar Filaments." Biomolecules 10, no. 11 (November 9, 2020): 1528. http://dx.doi.org/10.3390/biom10111528.
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The bacterial flagellar filament is an extracellular tubular protein structure that acts as a propeller for bacterial swimming motility. It is connected to the membrane-anchored rotary bacterial flagellar motor through a short hook. The bacterial flagellar filament consists of approximately 20,000 flagellins and can be several micrometers long. In this article, we reviewed the experimental works and models of flagellar filament construction and the recent findings of flagellar filament ejection during the cell cycle. The length-dependent decay of flagellar filament growth data supports the injection-diffusion model. The decay of flagellar growth rate is due to reduced transportation of long-distance diffusion and jamming. However, the filament is not a permeant structure. Several bacterial species actively abandon their flagella under starvation. Flagellum is disassembled when the rod is broken, resulting in an ejection of the filament with a partial rod and hook. The inner membrane component is then diffused on the membrane before further breakdown. These new findings open a new field of bacterial macro-molecule assembly, disassembly, and signal transduction.
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Elhadad, Dana, Prerak Desai, Galia Rahav, Michael McClelland, and Ohad Gal-Mor. "Flagellin Is Required for Host Cell Invasion and Normal Salmonella Pathogenicity Island 1 Expression by Salmonella enterica Serovar Paratyphi A." Infection and Immunity 83, no. 9 (June 8, 2015): 3355–68. http://dx.doi.org/10.1128/iai.00468-15.
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Salmonella entericaserovar Paratyphi A is a human-specific serovar that, together withSalmonella entericaserovar Typhi andSalmonella entericaserovar Sendai, causes enteric fever. Unlike the nontyphoidalSalmonella entericaserovar Typhimurium, the genomes ofS. Typhi andS. Paratyphi A are characterized by inactivation of multiple genes, including in the flagellum-chemotaxis pathway. Here, we explored the motility phenotype ofS. Paratyphi A and the role of flagellin in key virulence-associated phenotypes. Motility studies established that the human-adapted typhoidalS. Typhi,S. Paratyphi A, andS. Sendai are all noticeably less motile thanS. Typhimurium, and comparative transcriptome sequencing (RNA-Seq) showed that inS. Paratyphi A, the entire motility-chemotaxis regulon is expressed at significantly lowers levels than inS. Typhimurium. Nevertheless,S. Paratyphi A, likeS. Typhimurium, requires a functional flagellum for epithelial cell invasion and macrophage uptake, probably in a motility-independent mechanism. In contrast, flagella were found to be dispensable for host cell adhesion. Moreover, we demonstrate that inS. Paratyphi A, but not inS. Typhimurium, the lack of flagellin results in increased transcription of the flagellar and theSalmonellapathogenicity island 1 (SPI-1) regulons in a FliZ-dependent manner and in oversecretion of SPI-1 effectors via type three secretion system 1. Collectively, these results suggest a novel regulatory linkage between flagellin and SPI-1 inS. Paratyphi A that does not occur inS. Typhimurium and demonstrate curious distinctions in motility and the expression of the flagellum-chemotaxis regulon between these clinically relevant pathogens.
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VanDyke, David J., John Wu, Sandy Y. M. Ng, Masaomi Kanbe, Bonnie Chaban, Shin-Ichi Aizawa, and Ken F. Jarrell. "Identification of a Putative Acetyltransferase Gene, MMP0350, Which Affects Proper Assembly of both Flagella and Pili in the Archaeon Methanococcus maripaludis." Journal of Bacteriology 190, no. 15 (June 6, 2008): 5300–5307. http://dx.doi.org/10.1128/jb.00474-08.
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ABSTRACT Glycosylation is a posttranslational modification utilized in all three domains of life. Compared to eukaryotic and bacterial systems, knowledge of the archaeal processes involved in glycosylation is limited. Recently, Methanococcus voltae flagellin proteins were found to have an N-linked trisaccharide necessary for proper flagellum assembly. Current analysis by mass spectrometry of Methanococcus maripaludis flagellin proteins also indicated the attachment of an N-glycan containing acetylated sugars. To identify genes involved in sugar biosynthesis in M. maripaludis, a putative acetyltransferase was targeted for in-frame deletion. Deletion of this gene (MMP0350) resulted in a flagellin molecular mass shift to a size comparable to that expected for underglycosylated or completely nonglycoslyated flagellins, as determined by immunoblotting. Assembled flagellar filaments were not observed by electron microscopy. Interestingly, the deletion also resulted in defective pilus anchoring. Mutant cells with a deletion of MMP0350 had very few, if any, pili attached to the cell surface compared to a nonflagellated but piliated strain. However, pili were obtained from culture supernatants of this strain, indicating that the defect was not in pilus assembly but in stable attachment to the cell surface. Complementation of MMP0350 on a plasmid restored pilus attachment, but it was unable to restore flagellation, likely because the mutant ceased to make detectable flagellin. These findings represent the first report of a biosynthetic gene involved in flagellin glycosylation in archaea. Also, it is the first gene to be associated with pili, linking flagellum and pilus structure and assembly through posttranslational modifications.
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Albert-Weissenberger, Christiane, Tobias Sahr, Odile Sismeiro, Jörg Hacker, Klaus Heuner, and Carmen Buchrieser. "Control of Flagellar Gene Regulation in Legionella pneumophila and Its Relation to Growth Phase." Journal of Bacteriology 192, no. 2 (November 13, 2009): 446–55. http://dx.doi.org/10.1128/jb.00610-09.
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ABSTRACT The bacterial pathogen Legionella pneumophila responds to environmental changes by differentiation. At least two forms are well described: replicative bacteria are avirulent; in contrast, transmissive bacteria express virulence traits and flagella. Phenotypic analysis, Western blotting, and electron microscopy of mutants of the regulatory genes encoding RpoN, FleQ, FleR, and FliA demonstrated that flagellin expression is strongly repressed and that the mutants are nonflagellated in the transmissive phase. Transcriptome analyses elucidated that RpoN, together with FleQ, enhances transcription of 14 out of 31 flagellar class II genes, which code for the basal body, hook, and regulatory proteins. Unexpectedly, FleQ independent of RpoN enhances the transcription of fliA encoding sigma 28. Expression analysis of a fliA mutant showed that FliA activates three out of the five remaining flagellar class III genes and the flagellar class IV genes. Surprisingly, FleR does not induce but inhibits expression of at least 14 flagellar class III genes on the transcriptional level. Thus, we propose that flagellar class II genes are controlled by FleQ and RpoN, whereas the transcription of the class III gene fliA is controlled in a FleQ-dependent but RpoN-independent manner. However, RpoN and FleR might influence flagellin synthesis on a posttranscriptional level. In contrast to the commonly accepted view that enhancer-binding proteins such as FleQ always interact with RpoN to fullfill their regulatory functions, our results strongly indicate that FleQ regulates gene expression that is RpoN dependent and RpoN independent. Finally, FliA induces expression of flagellar class III and IV genes leading to the complete synthesis of the flagellum.
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del Campo, Ana Martínez, Teresa Ballado, Javier de la Mora, Sebastian Poggio, Laura Camarena, and Georges Dreyfus. "Chemotactic Control of the Two Flagellar Systems of Rhodobacter sphaeroides Is Mediated by Different Sets of CheY and FliM Proteins." Journal of Bacteriology 189, no. 22 (September 21, 2007): 8397–401. http://dx.doi.org/10.1128/jb.00730-07.
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ABSTRACT Rhodobacter sphaeroides expresses two different flagellar systems, a subpolar flagellum (fla1) and multiple polar flagella (fla2). These structures are encoded by different sets of flagellar genes. The chemotactic control of the subpolar flagellum (fla1) is mediated by three of the six different CheY proteins (CheY6, CheY4, or CheY3). We show evidence that CheY1, CheY2, and CheY5 control the chemotactic behavior mediated by fla2 flagella and that RSP6099 encodes the fla2 FliM protein.
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Nedeljković, Marko, Diego Emiliano Sastre, and Eric John Sundberg. "Bacterial Flagellar Filament: A Supramolecular Multifunctional Nanostructure." International Journal of Molecular Sciences 22, no. 14 (July 14, 2021): 7521. http://dx.doi.org/10.3390/ijms22147521.
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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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Lane, M. Chelsea, Virginia Lockatell, Greta Monterosso, Daniel Lamphier, Julia Weinert, J. Richard Hebel, David E. Johnson, and Harry L. T. Mobley. "Role of Motility in the Colonization of Uropathogenic Escherichia coli in the Urinary Tract." Infection and Immunity 73, no. 11 (November 2005): 7644–56. http://dx.doi.org/10.1128/iai.73.11.7644-7656.2005.
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ABSTRACT Uropathogenic Escherichia coli (UPEC) causes most uncomplicated urinary tract infections (UTIs) in humans. Flagellum-mediated motility and chemotaxis have been suggested to contribute to virulence by enabling UPEC to escape host immune responses and disperse to new sites within the urinary tract. To evaluate their contribution to virulence, six separate flagellar mutations were constructed in UPEC strain CFT073. The mutants constructed were shown to have four different flagellar phenotypes: fliA and fliC mutants do not produce flagella; the flgM mutant has similar levels of extracellular flagellin as the wild type but exhibits less motility than the wild type; the motAB mutant is nonmotile; and the cheW and cheY mutants are motile but nonchemotactic. Virulence was assessed by transurethral independent challenges and cochallenges of CBA mice with the wild type and each mutant. CFU/ml of urine or CFU/g bladder or kidney was determined 3 days postinoculation for the independent challenges and at 6, 16, 48, 60, and 72 h postinoculation for the cochallenges. While these mutants colonized the urinary tract during independent challenge, each of the mutants was outcompeted by the wild-type strain to various degrees at specific time points during cochallenge. Altogether, these results suggest that flagella and flagellum-mediated motility/chemotaxis may not be absolutely required for virulence but that these traits contribute to the fitness of UPEC and therefore significantly enhance the pathogenesis of UTIs caused by UPEC.
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Kirov, Sylvia M., Bronwen C. Tassell, Annalese B. T. Semmler, Lisa A. O’Donovan, Ali A. Rabaan, and Jonathan G. Shaw. "Lateral Flagella and Swarming Motility in Aeromonas Species." Journal of Bacteriology 184, no. 2 (January 15, 2002): 547–55. http://dx.doi.org/10.1128/jb.184.2.547-555.2002.
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ABSTRACT Swarming motility, a flagellum-dependent behavior that allows bacteria to move over solid surfaces, has been implicated in biofilm formation and bacterial virulence. In this study, light and electron microscopic analyses and genetic and functional investigations have shown that at least 50% of Aeromonas isolates from the species most commonly associated with diarrheal illness produce lateral flagella which mediate swarming motility. Aeromonas lateral flagella were optimally produced when bacteria were grown on solid medium for ≈8 h. Transmission and thin-section electron microscopy confirmed that these flagella do not possess a sheath structure. Southern analysis of Aeromonas reference strains and strains of mesophilic species (n = 84, varied sources and geographic regions) with a probe designed to detect lateral flagellin genes (lafA1 and lafA2) showed there was no marked species association of laf distribution. Approximately 50% of these strains hybridized strongly with the probe, in good agreement with the expression studies. We established a reproducible swarming assay (0.5% Eiken agar in Difco broth, 30°C) for Aeromonas spp. The laf-positive strains exhibited vigorous swarming motility, whereas laf-negative strains grew but showed no movement from the inoculation site. Light and scanning electron microscopic investigations revealed that lateral flagella formed bacterium-bacterium linkages on the agar surface. Strains of an Aeromonas caviae isolate in which lateral flagellum expression was abrogated by specific mutations in flagellar genes did not swarm, proving conclusively that lateral flagella are required for the surface movement. Whether lateral flagella and swarming motility contribute to Aeromonas intestinal colonization and virulence remains to be determined.
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Wan, Kirsty Y., Kyriacos C. Leptos, and Raymond E. Goldstein. "Lag, lock, sync, slip: the many ‘phases’ of coupled flagella." Journal of The Royal Society Interface 11, no. 94 (May 6, 2014): 20131160. http://dx.doi.org/10.1098/rsif.2013.1160.
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In a multitude of life's processes, cilia and flagella are found indispensable. Recently, the biflagellated chlorophyte alga Chlamydomonas has become a model organism for the study of ciliary motility and synchronization. Here, we use high-speed, high-resolution imaging of single pipette-held cells to quantify the rich dynamics exhibited by their flagella. Underlying this variability in behaviour are biological dissimilarities between the two flagella—termed cis and trans , with respect to a unique eyespot. With emphasis on the wild-type, we derive limit cycles and phase parametrizations for self-sustained flagellar oscillations from digitally tracked flagellar waveforms. Characterizing interflagellar phase synchrony via a simple model of coupled oscillators with noise, we find that during the canonical swimming breaststroke the cis flagellum is consistently phase-lagged relative to, while remaining robustly phase-locked with, the trans flagellum. Transient loss of synchrony, or phase slippage , may be triggered stochastically, in which the trans flagellum transitions to a second mode of beating with attenuated beat envelope and increased frequency. Further, exploiting this alga's ability for flagellar regeneration, we mechanically induced removal of one or the other flagellum of the same cell to reveal a striking disparity between the beatings of the cis and trans flagella, in isolation. These results are evaluated in the context of the dynamic coordination of Chlamydomonas flagella.
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Kim, Yun-Kyeong, and Linda L. McCarter. "Analysis of the Polar Flagellar Gene System ofVibrio parahaemolyticus." Journal of Bacteriology 182, no. 13 (July 1, 2000): 3693–704. http://dx.doi.org/10.1128/jb.182.13.3693-3704.2000.
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ABSTRACT Vibrio parahaemolyticus has dual flagellar systems adapted for locomotion under different circumstances. A single, sheathed polar flagellum propels the swimmer cell in liquid environments. Numerous unsheathed lateral flagella move the swarmer cell over surfaces. The polar flagellum is produced continuously, whereas the synthesis of lateral flagella is induced under conditions that impede the function of the polar flagellum, e.g., in viscous environments or on surfaces. Thus, the organism possesses two large gene networks that orchestrate polar and lateral flagellar gene expression and assembly. In addition, the polar flagellum functions as a mechanosensor controlling lateral gene expression. In order to gain insight into the genetic circuitry controlling motility and surface sensing, we have sought to define the polar flagellar gene system. The hierarchy of regulation appears to be different from the polar system of Caulobacter crescentus or the peritrichous system of enteric bacteria but is pertinent to many Vibrio andPseudomonas species. The gene identity and organization of 60 potential flagellar and chemotaxis genes are described. Conserved sequences are defined for two classes of polar flagellar promoters. Phenotypic and genotypic analysis of mutant strains with defects in swimming motility coupled with primer extension analysis of flagellar and chemotaxis transcription provides insight into the polar flagellar organelle, its assembly, and regulation of gene expression.
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Parthasarathy, G., Y. Yao, and K. S. Kim. "Flagella Promote Escherichia coli K1 Association with and Invasion of Human Brain Microvascular Endothelial Cells." Infection and Immunity 75, no. 6 (March 19, 2007): 2937–45. http://dx.doi.org/10.1128/iai.01543-06.
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ABSTRACT Escherichia coli containing the K1 capsule is the leading cause of gram-negative meningitis, but the pathogenesis of this disease is not completely understood. Recent microarray experiments in which we compared the gene expression profile of E. coli K1 associated with human brain microvascular endothelial cells (HBMEC) to the gene expression profile of E. coli K1 not associated with HBMEC revealed that there was a threefold increase in the expression of the fliI gene, encoding an ATP synthase involved in flagellar synthesis and motility, in HBMEC-associated E. coli. In this study, we examined the role of flagella in E. coli K1 association with and invasion of HBMEC by constructing isogenic ΔflhDC, ΔfliI, ΔfliC, and ΔcheW mutants that represented each class of flagellar genes. Mutations that affected the flagellum structure and flagellum formation (ΔflhDC, ΔfliI, and ΔfliC) resulted in significant defects in motility, as well as in HBMEC association and invasion, compared to the characteristics of the wild-type strain when preparations were examined with or without centrifugation. Transcomplementation with the corresponding genes restored the levels of these mutants to the levels of the parent strain. These findings suggest that the HBMEC association and invasion defects of the mutants are most likely related to flagella and less likely due to their motility defects. This conclusion was supported by our demonstration that the cheW mutant was not motile but was able to associate with and invade HBMEC. In addition, purified recombinant flagellin reduced the association of the wild-type strain with HBMEC by ∼40%, while it had no effect on the fliC mutant's association with HBMEC. Together, these findings indicate that flagella promote E. coli K1 binding to HBMEC.
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Merkx-Jacques, A., R. K. Obhi, G. Bethune, and C. Creuzenet. "The Helicobacter pylori flaA1 and wbpB Genes Control Lipopolysaccharide and Flagellum Synthesis and Function." Journal of Bacteriology 186, no. 8 (April 15, 2004): 2253–65. http://dx.doi.org/10.1128/jb.186.8.2253-2265.2004.
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ABSTRACT flaA1 and wbpB are conserved genes with unknown biological function in Helicobacter pylori. Since both genes are predicted to be involved in lipopolysaccharide (LPS) biosynthesis, flagellum assembly, or protein glycosylation, they could play an important role in the pathogenesis of H. pylori. To determine their biological role, both genes were disrupted in strain NCTC 11637. Both mutants exhibited altered LPS, with loss of most O-antigen and core modification, and increased sensitivity to sodium dodecyl sulfate compared to wild-type bacteria. These defects could be complemented in a gene-specific manner. Also, flaA1 could complement these defects in the wbpB mutant, suggesting a potential redundancy of the reductase activity encoded by both genes. Both mutants were nonmotile, although the wbpB mutant still produced flagella. The defect in the flagellum functionality of this mutant was not due to a defect in flagellin glycosylation since flagellins from wild-type strain NCTC 11637 were shown not to be glycosylated. The flaA1 mutant produced flagellins but no flagellum. Overall, the similar phenotypes observed for both mutants and the complementation of the wbpB mutant by flaA1 suggest that both genes belong to the same biosynthesis pathway. The data also suggest that flaA1 and wbpB are at the interface between several pathways that govern the expression of different virulence factors. We propose that FlaA1 and WbpB synthesize sugar derivatives dedicated to the glycosylation of proteins which are involved in LPS and flagellum production and that glycosylation regulates the activity of these proteins.
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Sander, Anna, Anja Zagrosek, Wolfgang Bredt, Emile Schiltz, Yves Piémont, Christa Lanz, and Christoph Dehio. "Characterization of Bartonella clarridgeiae Flagellin (FlaA) and Detection of Antiflagellin Antibodies in Patients with Lymphadenopathy." Journal of Clinical Microbiology 38, no. 8 (2000): 2943–48. http://dx.doi.org/10.1128/jcm.38.8.2943-2948.2000.
Full textAbstract:
Cat scratch disease (CSD) is a frequent clinical outcome ofBartonella henselae infection in humans. Recently, two case reports indicated Bartonella clarridgeiae as an additional causative agent of CSD. Both pathogens have been isolated from domestic cats, which are considered to be their natural reservoir. B. clarridgeiae and B. henselae can be distinguished phenotypically by the presence or absence of flagella, respectively. Separation of the protein content of purified flagella ofB. clarridgeiae by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblot analysis indicated that the flagellar filament is mainly composed of a polypeptide with a mass of 41 kDa. N-terminal sequencing of 20 amino acids of this protein revealed a perfect match to the N-terminal sequence of flagellin (FlaA) as deduced from the sequence of the flaA gene cloned from B. clarridgeiae. The flagellin of B. clarridgeiae is closely related to flagellins of Bartonella bacilliformis and several Bartonella-related bacteria. Since flagellar proteins are often immunodominant antigens, we investigated whether antibodies specific for the FlaA protein ofB. clarridgeiae are found in patients with CSD or lymphadenopathy. Immunoblotting with 724 sera of patients suffering from lymphadenopathy and 100 healthy controls indicated specific FlaA antibodies in 3.9% of the patients' sera but in none of the controls.B. clarridgeiae FlaA is thus antigenic and expressed in vivo, providing a valuable tool for serological testing. Our results further indicate that B. clarridgeiae might be a possible etiologic agent of CSD or lymphadenopathy. However, it remains to be clarified whether antibodies to the FlaA protein ofB. clarridgeiae are a useful indicator of acute infection.
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Sal, Melanie S., Chunhao Li, M. A. Motalab, Satoshi Shibata, Shin-Ichi Aizawa, and Nyles W. Charon. "Borrelia burgdorferi Uniquely Regulates Its Motility Genes and Has an Intricate Flagellar Hook-Basal Body Structure." Journal of Bacteriology 190, no. 6 (January 11, 2008): 1912–21. http://dx.doi.org/10.1128/jb.01421-07.
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ABSTRACT Borrelia burgdorferi is a flat-wave, motile spirochete that causes Lyme disease. Motility is provided by periplasmic flagella (PFs) located between the cell cylinder and an outer membrane sheath. The structure of these PFs, which are composed of a basal body, a hook, and a filament, is similar to the structure of flagella of other bacteria. To determine if hook formation influences flagellin gene transcription in B. burgdorferi, we inactivated the hook structural gene flgE by targeted mutagenesis. In many bacteria, completion of the hook structure serves as a checkpoint for transcriptional control of flagellum synthesis and other chemotaxis and motility genes. Specifically, the hook allows secretion of the anti-sigma factor FlgM and concomitant late gene transcription promoted by σ28. However, the control of B. burgdorferi PF synthesis differs from the control of flagellum synthesis in other bacteria; the gene encoding σ28 is not present in the genome of B. burgdorferi, nor are any σ28 promoter recognition sequences associated with the motility genes. We found that B. burgdorferi flgE mutants lacked PFs, were rod shaped, and were nonmotile, which substantiates previous evidence that PFs are involved in both cell morphology and motility. Although most motility and chemotaxis gene products accumulated at wild-type levels in the absence of FlgE, mutant cells had markedly decreased levels of the flagellar filament proteins FlaA and FlaB. Further analyses showed that the reduction in the levels of flagellin proteins in the spirochetes lacking FlgE was mediated at the posttranscriptional level. Taken together, our results indicate that in B. burgdorferi, the completion of the hook does not serve as a checkpoint for transcriptional regulation of flagellum synthesis. In addition, we also present evidence that the hook protein in B. burgdorferi forms a high-molecular-weight complex and that formation of this complex occurs in the periplasmic space.
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Malamud, Florencia, Pablo S. Torres, Roxana Roeschlin, Luciano A. Rigano, Ramón Enrique, Hernán R. Bonomi, Atilio P. Castagnaro, María Rosa Marano, and Adrián A. Vojnov. "The Xanthomonas axonopodis pv. citri flagellum is required for mature biofilm and canker development." Microbiology 157, no. 3 (March 1, 2011): 819–29. http://dx.doi.org/10.1099/mic.0.044255-0.
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Xanthomonas axonopodis pv. citri (Xac) is the causative agent of citrus canker. This bacterium develops a characteristic biofilm on both biotic and abiotic surfaces. To evaluate the participation of the single flagellum of Xac in biofilm formation, mutants in the fliC (flagellin) and the flgE (hook) genes were generated. Swimming motility, assessed on 0.25 % agar plates, was markedly reduced in fliC and flgE mutants. However, the fliC and flgE mutants exhibited a flagellar-independent surface translocation on 0.5 % agar plates. Mutation of either the rpfF or the rpfC gene, which both encode proteins involved in cell–cell signalling mediated by diffusible signal factor (DSF), led to a reduction in both flagellar-dependent and flagellar-independent surface translocation, indicating a regulatory role for DSF in both types of motility. Confocal laser scanning microscopy of biofilms produced in static culture demonstrated that the flagellum is also involved in the formation of mushroom-shaped structures and water channels, and in the dispersion of biofilms. The presence of the flagellum was required for mature biofilm development on lemon leaf surfaces. The absence of flagellin produced a slight reduction in Xac pathogenicity and this reduction was more severe when the complete flagellum structure was absent.
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Bouteiller, Mathilde, Charly Dupont, Yvann Bourigault, Xavier Latour, Corinne Barbey, Yoan Konto-Ghiorghi, and Annabelle Merieau. "Pseudomonas Flagella: Generalities and Specificities." International Journal of Molecular Sciences 22, no. 7 (March 24, 2021): 3337. http://dx.doi.org/10.3390/ijms22073337.
Full textAbstract:
Flagella-driven motility is an important trait for bacterial colonization and virulence. Flagella rotate and propel bacteria in liquid or semi-liquid media to ensure such bacterial fitness. Bacterial flagella are composed of three parts: a membrane complex, a flexible-hook, and a flagellin filament. The most widely studied models in terms of the flagellar apparatus are E. coli and Salmonella. However, there are many differences between these enteric bacteria and the bacteria of the Pseudomonas genus. Enteric bacteria possess peritrichous flagella, in contrast to Pseudomonads, which possess polar flagella. In addition, flagellar gene expression in Pseudomonas is under a four-tiered regulatory circuit, whereas enteric bacteria express flagellar genes in a three-step manner. Here, we use knowledge of E. coli and Salmonella flagella to describe the general properties of flagella and then focus on the specificities of Pseudomonas flagella. After a description of flagellar structure, which is highly conserved among Gram-negative bacteria, we focus on the steps of flagellar assembly that differ between enteric and polar-flagellated bacteria. In addition, we summarize generalities concerning the fuel used for the production and rotation of the flagellar macromolecular complex. The last part summarizes known regulatory pathways and potential links with the type-six secretion system (T6SS).
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Tripepi, Manuela, Saheed Imam, and Mechthild Pohlschröder. "Haloferax volcanii Flagella Are Required for Motility but Are Not Involved in PibD-Dependent Surface Adhesion." Journal of Bacteriology 192, no. 12 (April 2, 2010): 3093–102. http://dx.doi.org/10.1128/jb.00133-10.
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ABSTRACT Although the genome of Haloferax volcanii contains genes (flgA1-flgA2) that encode flagellins and others that encode proteins involved in flagellar assembly, previous reports have concluded that H. volcanii is nonmotile. Contrary to these reports, we have now identified conditions under which H. volcanii is motile. Moreover, we have determined that an H. volcanii deletion mutant lacking flagellin genes is not motile. However, unlike flagella characterized in other prokaryotes, including other archaea, the H. volcanii flagella do not appear to play a significant role in surface adhesion. While flagella often play similar functional roles in bacteria and archaea, the processes involved in the biosynthesis of archaeal flagella do not resemble those involved in assembling bacterial flagella but, instead, are similar to those involved in producing bacterial type IV pili. Consistent with this observation, we have determined that, in addition to disrupting preflagellin processing, deleting pibD, which encodes the preflagellin peptidase, prevents the maturation of other H. volcanii type IV pilin-like proteins. Moreover, in addition to abolishing swimming motility, and unlike the flgA1-flgA2 deletion, deleting pibD eliminates the ability of H. volcanii to adhere to a glass surface, indicating that a nonflagellar type IV pilus-like structure plays a critical role in H. volcanii surface adhesion.
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Arora, Shiwani K., Alice N. Neely, Barbara Blair, Stephen Lory, and Reuben Ramphal. "Role of Motility and Flagellin Glycosylation in the Pathogenesis of Pseudomonas aeruginosa Burn Wound Infections." Infection and Immunity 73, no. 7 (July 2005): 4395–98. http://dx.doi.org/10.1128/iai.73.7.4395-4398.2005.
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ABSTRACT In this study, we tested the contribution of flagellar motility, flagellin structure, and its glycosylation in Pseudomonas aeruginosa using genetically defined flagellar mutants. All mutants and their parent strains were tested in a burned-mouse model of infection. Motility and glycosylation of the flagellum appear to be important determinants of flagellar-mediated virulence in this model. This is the first report where genetically defined flagellar variants of P. aeruginosa were tested in the burned-mouse model of infection.
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Nakamura, Shuichi, and Tohru Minamino. "Flagella-Driven Motility of Bacteria." Biomolecules 9, no. 7 (July 14, 2019): 279. http://dx.doi.org/10.3390/biom9070279.
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The bacterial flagellum is a helical filamentous organelle responsible for motility. In bacterial species possessing flagella at the cell exterior, the long helical flagellar filament acts as a molecular screw to generate thrust. Meanwhile, the flagella of spirochetes reside within the periplasmic space and not only act as a cytoskeleton to determine the helicity of the cell body, but also rotate or undulate the helical cell body for propulsion. Despite structural diversity of the flagella among bacterial species, flagellated bacteria share a common rotary nanomachine, namely the flagellar motor, which is located at the base of the filament. The flagellar motor is composed of a rotor ring complex and multiple transmembrane stator units and converts the ion flux through an ion channel of each stator unit into the mechanical work required for motor rotation. Intracellular chemotactic signaling pathways regulate the direction of flagella-driven motility in response to changes in the environments, allowing bacteria to migrate towards more desirable environments for their survival. Recent experimental and theoretical studies have been deepening our understanding of the molecular mechanisms of the flagellar motor. In this review article, we describe the current understanding of the structure and dynamics of the bacterial flagellum.
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Faguy, David M., Ken F. Jarrell, John Kuzio, and Martin L. Kalmokoff. "Molecular analysis of archaeal flagellins: similarity to the type IV pilin – transport superfamily widespread in bacteria." Canadian Journal of Microbiology 40, no. 1 (January 1, 1994): 67–71. http://dx.doi.org/10.1139/m94-011.
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Ultrastructural, biochemical and genetic evidence has shown that the flagella and flagellin proteins from members of the archaea are distinct from their bacterial counterparts. The most important evidence is the sequence dissimilarity between archaeal and bacterial flagellins. We report here similarity between archaeal flagellins and members of the bacterial type IV pilin – transport superfamily. In addition to sequence similarity, the archaeal flagellins and the type IV pilin – transport superfamily share an unusual signal sequence cleavage site and may have functional parallels. This relationship has important implications for the assembly and biogenesis of archaeal flagella.Key words: flagellin, type IV pilin, homology, general secretion proteins, archaea.
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Sunter, Jack Daniel, Flavia Moreira-Leite, and Keith Gull. "Dependency relationships between IFT-dependent flagellum elongation and cell morphogenesis in Leishmania." Open Biology 8, no. 11 (November 2018): 180124. http://dx.doi.org/10.1098/rsob.180124.
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Flagella have multiple functions that are associated with different axonemal structures. Motile flagella typically have a 9 + 2 arrangement of microtubules, whereas sensory flagella normally have a 9 + 0 arrangement. Leishmania exhibits both of these flagellum forms and differentiation between these two flagellum forms is associated with cytoskeletal and cell shape changes. We disrupted flagellum elongation in Leishmania by deleting the intraflagellar transport (IFT) protein IFT140 and examined the effects on cell morphogenesis. Δift140 cells have no external flagellum, having only a very short flagellum within the flagellar pocket. This short flagellum had a collapsed 9 + 0 (9v) axoneme configuration reminiscent of that in the amastigote and was not attached to the pocket membrane. Although amastigote-like changes occurred in the flagellar cytoskeleton, the cytoskeletal structures of Δift140 cells retained their promastigote configurations, as examined by fluorescence microscopy of tagged proteins and serial electron tomography. Thus, Leishmania promastigote cell morphogenesis does not depend on the formation of a long flagellum attached at the neck. Furthermore, our data show that disruption of the IFT system is sufficient to produce a switch from the 9 + 2 to the collapsed 9 + 0 (9v) axonemal structure, echoing the process that occurs during the promastigote to amastigote differentiation.
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Dentler, WL, and C. Adams. "Flagellar microtubule dynamics in Chlamydomonas: cytochalasin D induces periods of microtubule shortening and elongation; and colchicine induces disassembly of the distal, but not proximal, half of the flagellum." Journal of Cell Biology 117, no. 6 (June 15, 1992): 1289–98. http://dx.doi.org/10.1083/jcb.117.6.1289.
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To study the mechanisms responsible for the regulation of flagellar length, we examined the effects of colchicine and Cytochalasin D (CD) on the growth and maintenance of Chlamydomonas flagella on motile wild type cells as well as on pf 18 cells, whose flagella lack the central microtubules and are immobile. CD had no effect on the regeneration of flagella after deflagellation but it induced fully assembled flagella to shorten at an average rate of 0.03 microns-min. Cells remained fully motile in CD and even stubby flagella continued to move, indicating that flagellar shortening did not selectively disrupt machinery necessary for motility. To observe the effects of the drug on individual cells, pf 18 cells were treated with CD and flagella on cells were monitored by direct observation over a 5-hour period. Flagella on control pf 18 cells maintained their initial lengths throughout the experiment but flagella on CD-treated cells exhibited periods of elongation, shortening, and regrowth suggestive of the dynamic behavior of cytoplasmic microtubules observed in vitro and in vitro. Cells behaved individually, with no two cells exhibiting the same flagellar behavior at any given time although both flagella on any single cell behaved identically. The rate of drug-induced flagellar shortening and elongation in pf 18 cells varied from 0.08 to 0.17 microns-min-1, with each event occurring over 10-60-min periods. Addition of colchicine to wild type and pf 18 cells induced flagella to shorten at an average rate of 0.06 microns-min-1 until the flagella reached an average of 73% of their initial length, after which they exhibited no further shortening or elongation. Cells treated with colchicine and CD exhibited nearly complete flagellar resorption, with little variation in flagellar length among cells. The effects of these drugs were reversible and flagella grew to normal stable lengths after drug removal. Taken together, these results show that the distal half to one-third of the Chlamydomonas flagellum is relatively unstable in the presence of colchicine but that the proximal half to two-thirds of the flagellum is stable to this drug. In contrast to colchicine, CD can induce nearly complete flagellar microtubule disassembly as well as flagellar assembly. Flagellar microtubules must, therefore, be inherently unstable, and flagellar length is stabilized by factors that are sensitive, either directly or indirectly, to the effects of CD.
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Poggio, Sebastian, Cei Abreu-Goodger, Salvador Fabela, Aurora Osorio, Georges Dreyfus, Pablo Vinuesa, and Laura Camarena. "A Complete Set of Flagellar Genes Acquired by Horizontal Transfer Coexists with the Endogenous Flagellar System in Rhodobacter sphaeroides." Journal of Bacteriology 189, no. 8 (February 9, 2007): 3208–16. http://dx.doi.org/10.1128/jb.01681-06.
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ABSTRACT Bacteria swim in liquid environments by means of a complex rotating structure known as the flagellum. Approximately 40 proteins are required for the assembly and functionality of this structure. Rhodobacter sphaeroides has two flagellar systems. One of these systems has been shown to be functional and is required for the synthesis of the well-characterized single subpolar flagellum, while the other was found only after the genome sequence of this bacterium was completed. In this work we found that the second flagellar system of R. sphaeroides can be expressed and produces a functional flagellum. In many bacteria with two flagellar systems, one is required for swimming, while the other allows movement in denser environments by producing a large number of flagella over the entire cell surface. In contrast, the second flagellar system of R. sphaeroides produces polar flagella that are required for swimming. Expression of the second set of flagellar genes seems to be positively regulated under anaerobic growth conditions. Phylogenic analysis suggests that the flagellar system that was initially characterized was in fact acquired by horizontal transfer from a γ-proteobacterium, while the second flagellar system contains the native genes. Interestingly, other α-proteobacteria closely related to R. sphaeroides have also acquired a set of flagellar genes similar to the set found in R. sphaeroides, suggesting that a common ancestor received this gene cluster.
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Tomich, Mladen, Christine A. Herfst, Joseph W. Golden, and Christian D. Mohr. "Role of Flagella in Host Cell Invasion by Burkholderia cepacia." Infection and Immunity 70, no. 4 (April 2002): 1799–806. http://dx.doi.org/10.1128/iai.70.4.1799-1806.2002.
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ABSTRACT Burkholderia cepacia is an important opportunistic human pathogen that affects immunocompromised individuals, particularly cystic fibrosis (CF) patients. Colonization of the lungs of a CF patient by B. cepacia can lead not only to a decline in respiratory function but also to an acute systemic infection, such as bacteremia. We have previously demonstrated that a CF clinical isolate of B. cepacia, strain J2315, can invade and survive within cultured respiratory epithelial cells. In order to further characterize the mechanisms of invasion of B. cepacia, we screened a transposon-generated mutant library of strain J2315 for mutants defective in invasion of A549 respiratory epithelial cells. Here we describe isolation and characterization of a nonmotile mutant of B. cepacia with reduced invasiveness due to disruption of fliG, which encodes a component of the motor-switch complex of the flagellar basal body. We also found that a defined null mutation in fliI, a gene encoding a highly conserved ATPase required for protein translocation via the flagellar type III secretion system, also resulted in loss of motility and a significant reduction in invasion. Both mutants lacked detectable intracellular flagellin and failed to export detectable amounts of flagellin into culture supernatants, suggesting that disruption of fliG and fliI impaired flagellar biogenesis. The reduction in invasion did not appear to be due to defective adherence of the flagellar mutants to A549 cells, suggesting that functional flagella and motility are required for full invasiveness of B. cepacia. Our findings indicate that flagellum-mediated motility may facilitate penetration of host epithelial barriers by B. cepacia, contributing to establishment of infection and systemic spread of the organism.
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Lepka, Daniela, and Gottfried Wilharm. "Flagellin genes of Yersinia enterocolitica biotype 1A: playground of evolution towards novel flagellin functions." Microbiology Research 1, no. 1 (December 9, 2010): 7. http://dx.doi.org/10.4081/mr.2010.e7.
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Yersinia enterocolitica strain 8081, representing the high-pathogenic biotype 1B, harbours three flagellin genes arranged in tandem in the order fliC3, fliC, fliC2. The genes are organized monocistronic but coordinately expressed under the control of the flagellar sigma factor. No sequence data is available on flagellins of low-pathogenic Y. enterocolitica biotypes 2-5 and of biotype 1A strains, appearing non-pathogenic in the mouse infection model. We sequenced the flagellin genes of ten biotype 1A and biotype 4 isolates, respectively. While we could not identify any sequence polymorphism among flagellin genes of biotype 4 isolates, we found that biotype 1A strains harbour three variable flagellin genes. Moreover, three biotype 1A isolates exhibited a rearranged flagellin gene order and at least one rearranged flagellin gene was apparently acquired by horizontal gene transfer. The variability of flagellin genes seems to mirror evolution towards novel flagellin functions. By contrast, strictly conserved flagellins of biotype 4 isolates point at a strong selection pressure such as expected to be imposed by an important function in the context of infection.
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Dentler, William. "Intraflagellar transport (IFT) during assembly and disassembly of Chlamydomonas flagella." Journal of Cell Biology 170, no. 4 (August 15, 2005): 649–59. http://dx.doi.org/10.1083/jcb.200412021.
Full textAbstract:
Intraflagellar transport (IFT) of particles along flagellar microtubules is required for the assembly and maintenance of eukaryotic flagella and cilia. In Chlamydomonas, anterograde and retrograde particles viewed by light microscopy average 0.12-μm and 0.06-μm diameter, respectively. Examination of IFT particle structure in growing flagella by electron microscopy revealed similar size aggregates composed of small particles linked to each other and to the membrane and microtubules. To determine the relationship between the number of particles and flagellar length, the rate and frequency of IFT particle movement was measured in nongrowing, growing, and shortening flagella. In all flagella, anterograde and retrograde IFT averaged 1.9 μm/s and 2.7 μm/s, respectively, but retrograde IFT was significantly slower in flagella shorter than 4 μm. The number of flagellar IFT particles was not fixed, but depended on flagellar length. Pauses in IFT particle entry into flagella suggest the presence of a periodic “gate” that permits up to 4 particles/s to enter a flagellum.