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Tyrosine Nitration of Flagellins: a Response of Sinorhizobium meliloti to Nitrosative Stress. Appl Environ Microbiol 2020; 87:AEM.02210-20. [PMID: 33067191 DOI: 10.1128/aem.02210-20] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2020] [Accepted: 10/13/2020] [Indexed: 12/13/2022] Open
Abstract
Rhizobia are bacteria which can either live as free organisms in the soil or interact with plants of the legume family with, as a result, the formation of root organs called nodules in which differentiated endosymbiotic bacteria fix atmospheric nitrogen to the plant's benefit. In both lifestyles, rhizobia are exposed to nitric oxide (NO) which can be perceived as a signaling or toxic molecule. NO can act at the transcriptional level but can also modify proteins by S-nitrosylation of cysteine or nitration of tyrosine residues. However, only a few molecular targets of NO have been described in bacteria and none of them have been characterized in rhizobia. Here, we examined tyrosine nitration of Sinorhizobium meliloti proteins induced by NO. We found three tyrosine-nitrated proteins in S. meliloti grown under free-living conditions, in response to an NO donor. Two nitroproteins were identified by mass spectrometry and correspond to flagellins A and B. We showed that one of the nitratable tyrosines is essential to flagellin function in motility.IMPORTANCE Rhizobia are found as free-living bacteria in the soil or in interaction with plants and are exposed to nitric oxide (NO) in both environments. NO is known to have many effects on animals, plants, and bacteria where only a few molecular targets of NO have been described so far. We identified flagellin A and B by mass spectrometry as tyrosine-nitrated proteins in Sinorhizobium meliloti in vivo We also showed that one of the nitratable tyrosines is essential to flagellin function in motility. The results enhanced our understanding of NO effects on rhizobia. Identification of bacterial flagellin nitration opens a new possible role of NO in plant-microbe interactions.
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Hernández-Salmerón JE, Valencia-Cantero E, Santoyo G. Genome-wide analysis of long, exact DNA repeats in rhizobia. Genes Genomics 2013. [DOI: 10.1007/s13258-012-0052-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tambalo DD, Bustard DE, Del Bel KL, Koval SF, Khan MF, Hynes MF. Characterization and functional analysis of seven flagellin genes in Rhizobium leguminosarum bv. viciae. Characterization of R. leguminosarum flagellins. BMC Microbiol 2010; 10:219. [PMID: 20716375 PMCID: PMC2936354 DOI: 10.1186/1471-2180-10-219] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2010] [Accepted: 08/17/2010] [Indexed: 11/29/2022] Open
Abstract
Background Rhizobium leguminosarum bv. viciae establishes symbiotic nitrogen fixing partnerships with plant species belonging to the Tribe Vicieae, which includes the genera Vicia, Lathyrus, Pisum and Lens. Motility and chemotaxis are important in the ecology of R. leguminosarum to provide a competitive advantage during the early steps of nodulation, but the mechanisms of motility and flagellar assembly remain poorly studied. This paper addresses the role of the seven flagellin genes in producing a functional flagellum. Results R. leguminosarum strains 3841 and VF39SM have seven flagellin genes (flaA, flaB, flaC, flaD, flaE, flaH, and flaG), which are transcribed separately. The predicted flagellins of 3841 are highly similar or identical to the corresponding flagellins in VF39SM. flaA, flaB, flaC, and flaD are in tandem array and are located in the main flagellar gene cluster. flaH and flaG are located outside of the flagellar/motility region while flaE is plasmid-borne. Five flagellin subunits (FlaA, FlaB, FlaC, FlaE, and FlaG) are highly similar to each other, whereas FlaD and FlaH are more distantly related. All flagellins exhibit conserved amino acid residues at the N- and C-terminal ends and are variable in the central regions. Strain 3841 has 1-3 plain subpolar flagella while strain VF39SM exhibits 4-7 plain peritrichous flagella. Three flagellins (FlaA/B/C) and five flagellins (FlaA/B/C/E/G) were detected by mass spectrometry in the flagellar filaments of strains 3841 and VF39SM, respectively. Mutation of flaA resulted in non-motile VF39SM and extremely reduced motility in 3841. Individual mutations of flaB and flaC resulted in shorter flagellar filaments and consequently reduced swimming and swarming motility for both strains. Mutant VF39SM strains carrying individual mutations in flaD, flaE, flaH, and flaG were not significantly affected in motility and filament morphology. The flagellar filament and the motility of 3841 strains with mutations in flaD and flaG were not significantly affected while flaE and flaH mutants exhibited shortened filaments and reduced swimming motility. Conclusion The results obtained from this study demonstrate that FlaA, FlaB, and FlaC are major components of the flagellar filament while FlaD and FlaG are minor components for R. leguminosarum strains 3841 and VF39SM. We also observed differences between the two strains, wherein FlaE and FlaH appear to be minor components of the flagellar filaments in VF39SM but these flagellin subunits may play more important roles in 3841. This paper also demonstrates that the flagellins of 3841 and VF39SM are possibly glycosylated.
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Affiliation(s)
- Dinah D Tambalo
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, AB T2N1N4, Canada
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Orozco-Mosqueda MDC, Altamirano-Hernandez J, Farias-Rodriguez R, Valencia-Cantero E, Santoyo G. Homologous recombination and dynamics of rhizobial genomes. Res Microbiol 2009; 160:733-41. [DOI: 10.1016/j.resmic.2009.09.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2009] [Revised: 09/17/2009] [Accepted: 09/21/2009] [Indexed: 10/20/2022]
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Brencic A, Winans SC. Detection of and response to signals involved in host-microbe interactions by plant-associated bacteria. Microbiol Mol Biol Rev 2005; 69:155-94. [PMID: 15755957 PMCID: PMC1082791 DOI: 10.1128/mmbr.69.1.155-194.2005] [Citation(s) in RCA: 185] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Diverse interactions between hosts and microbes are initiated by the detection of host-released chemical signals. Detection of these signals leads to altered patterns of gene expression that culminate in specific and adaptive changes in bacterial physiology that are required for these associations. This concept was first demonstrated for the members of the family Rhizobiaceae and was later found to apply to many other plant-associated bacteria as well as to microbes that colonize human and animal hosts. The family Rhizobiaceae includes various genera of rhizobia as well as species of Agrobacterium. Rhizobia are symbionts of legumes, which fix nitrogen within root nodules, while Agrobacterium tumefaciens is a pathogen that causes crown gall tumors on a wide variety of plants. The plant-released signals that are recognized by these bacteria are low-molecular-weight, diffusible molecules and are detected by the bacteria through specific receptor proteins. Similar phenomena are observed with other plant pathogens, including Pseudomonas syringae, Ralstonia solanacearum, and Erwinia spp., although here the signals and signal receptors are not as well defined. In some cases, nutritional conditions such as iron limitation or the lack of nitrogen sources seem to provide a significant cue. While much has been learned about the process of host detection over the past 20 years, our knowledge is far from being complete. The complex nature of the plant-microbe interactions makes it extremely challenging to gain a comprehensive picture of host detection in natural environments, and thus many signals and signal recognition systems remain to be described.
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Affiliation(s)
- Anja Brencic
- Department of Microbiology, 361A Wing Hall, Cornell University, Ithaca, NY 14853, USA
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Yao SY, Luo L, Har KJ, Becker A, Rüberg S, Yu GQ, Zhu JB, Cheng HP. Sinorhizobium meliloti ExoR and ExoS proteins regulate both succinoglycan and flagellum production. J Bacteriol 2004; 186:6042-9. [PMID: 15342573 PMCID: PMC515170 DOI: 10.1128/jb.186.18.6042-6049.2004] [Citation(s) in RCA: 87] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The production of the Sinorhizobium meliloti exopolysaccharide, succinoglycan, is required for the formation of infection threads inside root hairs, a critical step during the nodulation of alfalfa (Medicago sativa) by S. meliloti. Two bacterial mutations, exoR95::Tn5 and exoS96::Tn5, resulted in the overproduction of succinoglycan and a reduction in symbiosis. Systematic analyses of the symbiotic phenotypes of the two mutants demonstrated their reduced efficiency of root hair colonization. In addition, both the exoR95 and exoS96 mutations caused a marked reduction in the biosynthesis of flagella and consequent loss of ability of the cells to swarm and swim. Succinoglycan overproduction did not appear to be the cause of the suppression of flagellum biosynthesis. Further analysis indicated that both the exoR95 and exoS96 mutations affected the expression of the flagellum biosynthesis genes. These findings suggest that both the ExoR protein and the ExoS/ChvI two-component regulatory system are involved in the regulation of both succinoglycan and flagellum biosynthesis. These findings provide new avenues of understanding of the physiological changes S. meliloti cells go through during the early stages of symbiosis and of the signal transduction pathways that mediate such changes.
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Affiliation(s)
- Shi-Yi Yao
- Biological Sciences Department, Lehman College, The City University of New York, 250 Bedford Park Blvd., West, Bronx, NY 10468, USA
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Ely B, Ely TW, Crymes WB, Minnich SA. A family of six flagellin genes contributes to the Caulobacter crescentus flagellar filament. J Bacteriol 2000; 182:5001-4. [PMID: 10940048 PMCID: PMC111384 DOI: 10.1128/jb.182.17.5001-5004.2000] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2000] [Accepted: 06/08/2000] [Indexed: 11/20/2022] Open
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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Affiliation(s)
- B Ely
- Department of Biological Sciences, University of South Carolina, Columbia, South Carolina 29208, USA.
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Wei X, Bauer WD. Tn5-induced and spontaneous switching of Sinorhizobium meliloti to faster-swarming behavior. Appl Environ Microbiol 1999; 65:1228-35. [PMID: 10049888 PMCID: PMC91169 DOI: 10.1128/aem.65.3.1228-1235.1999] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Tn5 mutants of Sinorhizobium meliloti RMB7201 which swarmed 1.5 to 2. 5 times faster than the parental strain in semisolid agar, moist sand, and viscous liquid were identified. These faster-swarming (FS) mutants outgrew the wild type 30- to 40-fold within 2 days in mixed swarm colonies. The FS mutants survived and grew as well as or better than the wild type under all of the circumstances tested, except in a soil matrix subjected to air drying. Exopolysaccharide (EPS) synthesis was reduced in each of the FS mutants when they were grown on defined succinate-nitrate medium, but the extent of reduction was different for each. It appears that FS behavior likely results from a modest, general derepression of motility involving an increased proportion of motile and flagellated cells and an increased average number of flagella per cell and increased average flagellar length. Spontaneous FS variants of RMB7201 were obtained at a frequency of about 1 per 10,000 to 20,000 cells by either enrichment from the periphery of swarm colonies or screening of colonies for reduced EPS synthesis on succinate-nitrate plates. The spontaneous FS variants and Tn5 FS mutants were symbiotically effective and competitive in alfalfa nodulation. Reversion of FS variants to wild-type behavior was sporadic, indicating that reversion is affected by unidentified environmental factors. Based on phenotypic and molecular differences between individual FS variants and mutants, it appears that there may be multiple genetic configurations that result in FS behavior in RMB7201. The facile isolation of spontaneous FS variants of Escherichia coli and Pseudomonas aeruginosa indicates that switching to FS behavior may be fairly common among bacterial species. The substantial growth advantage of FS mutants and variants wherever nutrient gradients exist suggests that switching to FS forms may be an important behavioral adaptation in natural environments.
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Affiliation(s)
- X Wei
- Department of Plant Biology, Ohio State University, Columbus, Ohio 43210, USA
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Rodríguez C, Romero D. Multiple recombination events maintain sequence identity among members of the nitrogenase multigene family in Rhizobium etli. Genetics 1998; 149:785-94. [PMID: 9611191 PMCID: PMC1460202 DOI: 10.1093/genetics/149.2.785] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
A distinctive characteristic of the Rhizobium genome is the frequent finding of reiterated sequences, which often constitute multigene families. Interestingly, these families usually maintain a high degree of nucleotide sequence identity. It is commonly assumed that apparent gene conversion between reiterated elements might lead to concerted variation among members of a multigene family. However, the operation of this mechanism has not yet been demonstrated in the Rhizobiaceae. In this work, we employed different genetic constructions to address the role of apparent gene conversion as a homogenizing mechanism between members of the plasmid-located nitrogenase multigene family in Rhizobium etli. Our results show that a 28-bp insertion into one of the nitrogenase reiterations can be corrected by multiple recombination events, including apparent gene conversion. The correction process was dependent on the presence of both a wild-type recA gene and wild-type copies of the nitrogenase reiterations. Frequencies of apparent gene conversion to the wild-type nitrogenase reiterations were the same when the insertion to be corrected was located either in cis or in trans, indicating that this event frequently occurs through intermolecular interactions. Interestingly, a high frequency of multiple crossovers was observed, suggesting that these large plasmid molecules are engaging repeatedly in recombination events, in a situation akin to phage recombination or recombination among small, high-copy number plasmids.
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Affiliation(s)
- C Rodríguez
- Departamento de Genética Molecular, Centro de Investigación sobre Fijación de Nitrógeno, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, México
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Abstract
Data for further development of the flagellar antigen genetics of the species Escherichia coli are reported. Two new flagellin genes named fllA and flmA were found in E. coli 781-55, E2987-73, and E223-69, the test strains for E. coli flagellar antigens H44, H55, and H54, respectively (collection of the International Escherichia and Klebsiella Centre of the World Health Organization, Copenhagen, Denmark). Two alleles of fllA were identified that encode flagellar antigens H44 (fllA44) and H55 (fllA55), and the only flmA allele found (flmA54) encodes antigen H54. The sites of their integration in the E. coli K-12 chromosome after P1-mediated transduction were approximately determined and found to be separate from each other and from the known regions of flagellar genes of E. coli and salmonellae. The region of flm54 was found to repress the expression of some alleles of the flagellin gene fliC. In addition, cryptic genes encoding antigens H4 and H38 were found in phenotypically monophasic test strains 781-55 and E2987-73, respectively.
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Affiliation(s)
- Y A Ratiner
- Department of Microbiology, Mechnikov Research Institute for Vaccines and Sera (Russian Academy of Medical Science), Moscow
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Abstract
Bartonella bacilliformis was perhaps the most lethal bacterial human pathogen in the pre-antibiotic era, but infections were and are limited to a specific geographical area, largely in Peru, corresponding to the range of its sand fly vector. B. bacilliformis targets both red cells and endothelial cells. Recent phylogenetic realignments have revealed a close genetic relationship to other bacteria which cause human diseases, including bacterial angiomatosis, to the former Grahamella species which infect red cells in other mammals, and to plant pathogens and symbionts including Agrobacterium tumefaciens and Rhizobium meliloti. Features of B. bacilliformis that contribute to its pathogenesis are slowly coming into view, and are here reviewed.
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Affiliation(s)
- G M Ihler
- Department of Medical Biochemistry and Genetics, College of Medicine, TAMU Health Science Center, College Station 77843-1114, USA.
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12
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Vanderleyden J. Surface Properties and Motility of Rhizobium and Azospirillum in Relation to Plant Root Attachment. MICROBIAL ECOLOGY 1996; 32:149-169. [PMID: 8688006 DOI: 10.1007/bf00185885] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Plant growth promotion by rhizobacteria is a widely spread phenomenon. However only a few rhizobacteria have been studied thoroughly. Rhizobium is the best-studied rhizobacterium. It forms a symbiosis with a restricted host range. Azospirillum is another plant-growth-promoting rhizobacterium which forms rhizocoenoses with a wide range of plants. In both bacteria, the interaction with the plant involves the attraction toward the host plant and the attachment to the surface of the root. Both bacteria are attracted to plant roots, but differ in specificity. Attachment to plant roots occurs in two steps for both bacteria: a quick, reversible adsorption, and a slow, irreversible anchoring to the plant root surface. However, for the two systems under study, the bacterial surface molecules involved in plant root attachment are not necessarily the same.
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McCarter LL. Genetic and molecular characterization of the polar flagellum of Vibrio parahaemolyticus. J Bacteriol 1995; 177:1595-609. [PMID: 7883718 PMCID: PMC176778 DOI: 10.1128/jb.177.6.1595-1609.1995] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
Vibrio parahaemolyticus possesses two alternate flagellar systems adapted for movement under different circumstances. A single polar flagellum propels the bacterium in liquid (swimming), while multiple lateral flagella move the bacterium over surfaces (swarming). Energy to rotate the polar flagellum is derived from the sodium membrane potential, whereas lateral flagella are powered by the proton motive force. Lateral flagella are arranged peritrichously, and the unsheathed filaments are polymerized from a single flagellin. The polar flagellum is synthesized constitutively, but lateral flagella are produced only under conditions in which the polar flagellum is not functional, e.g., on surfaces. This work initiates characterization of the sheathed, polar flagellum. Four genes encoding flagellins were cloned and found to map in two loci. These genes, as well as three genes encoding proteins resembling HAPs (hook-associated proteins), were sequenced. A potential consensus polar flagellar promoter was identified by using upstream sequences from seven polar genes. It resembled the enterobacterial sigma 28 consensus promoter. Three of the four flagellin genes were expressed in Escherichia coli, and expression was dependent on the product of the fliA gene encoding sigma 28. The fourth flagellin gene may be different regulated. It was not expressed in E. coli, and inspection of upstream sequence revealed a potential sigma 54 consensus promoter. Mutants with single and multiple defects in flagellin genes were constructed in order to determine assembly rules for filament polymerization. HAP mutants displayed new phenotypes, which were different from those of Salmonella typhimurium and most probably were the result of the filament being sheathed.
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Affiliation(s)
- L L McCarter
- Immunology Department, Scripps Research Institute, La Jolla, California 92037
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14
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Finan TM, Gough C, Truchet G. Similarity between the Rhizobium meliloti fliP gene and pathogenicity-associated genes from animal and plant pathogens. Gene X 1995; 152:65-7. [PMID: 7828930 DOI: 10.1016/0378-1119(94)00643-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The nucleotide sequence of the Rhizobium meliloti (Rm) fliP gene was determined. Rm strains carrying insertions within this gene were non-motile, lacked flagella and formed normal N2-fixing root nodules on alfalfa. The FliP protein showed similarity to several bacterial gene products involved in pathogenicity in both plant and animal pathogens. It is likely that all of these proteins share a common functional role in the secretion of specific proteins from bacterial cells.
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Affiliation(s)
- T M Finan
- Department of Biology, McMaster University, Hamilton, Ontario, Canada
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15
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Schoenhals G, Whitfield C. Comparative analysis of flagellin sequences from Escherichia coli strains possessing serologically distinct flagellar filaments with a shared complex surface pattern. J Bacteriol 1993; 175:5395-402. [PMID: 8366026 PMCID: PMC206594 DOI: 10.1128/jb.175.17.5395-5402.1993] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023] Open
Abstract
Escherichia coli morphotype E flagellar filaments have a characteristic surface pattern of short-pitch loops when examined by electron microscopy. Seven of the 50 known E. coli H (flagellar antigen) serotypes (H1, H7, H12, H23, H45, H49, and H51) produce morphotype E filaments. Polymerase chain reaction was used to amplify flagellin structural (fliC) genes from E. coli strains producing morphotype E flagellar filaments and from strains with flagellar filaments representing other morphotypes. A single DNA fragment was obtained from each strain, and the size of the amplified DNA correlated with the molecular mass of the corresponding flagellin protein. This finding and hybridization data suggest that these bacteria are monophasic. fliC genes from three E. coli serotypes (H1, H7, and H12) possessing morphotype E flagellar filaments were sequenced in order to assess the contribution of conserved flagellin primary sequence to the characteristic filament architecture. The H1 and H12 fliC sequences were identical in length (1,788 bp), while the H7 fliC sequence was shorter (1,755 bp). The deduced molecular masses of the FliC proteins were 60,857 Da (H1), 59,722 Da (H7), and 60,978 Da (H12). The H1, H7, and H12 flagellins demonstrated 98 to 99% identity over the amino-terminal region (190 amino acid residues) and 89% (H7) to 99% (H1 and H12) identity in the carboxy-terminal region (100 amino acid residues). The complete primary amino acid sequences for H1 and H12 flagellins differed by only 10 amino acids, accounting for previously reported serological cross-reactions. However, the central region of H7 flagellin had only 38% identity with H1 and H12 flagellins. The characteristic morphology of morphotype E flagellar filaments is therefore not dependent on a highly conserved primary sequence within the exposed central region. Comparison of morphotype E E. coli flagellins with those from E. coli K-12, Serratia marcescens, and several Salmonella serovars supported the established concept of highly conserved terminal regions flanking a variable central region.
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Affiliation(s)
- G Schoenhals
- Department of Microbiology, College of Biological Sciences, University of Guelph, Ontario, Canada
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Robinson JB, Tuovinen OH, Bauer WD. Role of divalent cations in the subunit associations of complex flagella from Rhizobium meliloti. J Bacteriol 1992; 174:3896-902. [PMID: 1597412 PMCID: PMC206097 DOI: 10.1128/jb.174.12.3896-3902.1992] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Rhizobium meliloti, a symbiotic, nitrogen-fixing soil bacterium with complex flagella, as well as other members of the family Rhizobiaceae, rapidly lost motility when suspended in buffers lacking divalent cations but retained good motility in buffers containing calcium, magnesium, barium, or strontium. Loss of motility was associated with loss of flagella from the cells. Analysis of flagella by sedimentation, gel electrophoresis, and electron microscopy revealed that removal of divalent cations from the complex flagella of R. meliloti resulted in extensive dissociation of the flagellar filaments into low-molecular-weight subunits. Accordingly, divalent cations such as calcium and magnesium that are normally present at high concentrations in the soil solution may be crucial to the assembly and rigidity of complex flagella.
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Affiliation(s)
- J B Robinson
- Department of Agronomy, Ohio State University, Columbus 43210
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Matthijs G, Marynen P. A deletion polymorphism in the human alpha-2-macroglobulin (A2M) gene. Nucleic Acids Res 1991; 19:5102. [PMID: 1717945 PMCID: PMC328855 DOI: 10.1093/nar/19.18.5102] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Affiliation(s)
- G Matthijs
- Center for Human Genetics, University of Leuven, Belgium
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18
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New nucleotide sequence data on the EMBL File Server. Nucleic Acids Res 1991; 19:5103-10. [PMID: 1923795 PMCID: PMC328856 DOI: 10.1093/nar/19.18.5103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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