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PubMed1999

Flagella modulate the multicellular behavior of Salmonella typhimurium on the community level.

Salmonella typhimurium strains MAE52 and MAE32 display a constitutive multicellular morphotype mediated by the expression of the agfD operon. In those strains, the role of flagella in the formation of various modes of multicellular behavior was investigated. Flagella were not required for the formation of the multicellular morphotype (rdar) on plates. However, visual examination showed that the global behavior of the bacterial community on air-liquid, surface-liquid or cell-cell-liquid interfaces changed in the absence of flagella. No differences in the local cell-cell interactions were observed at the microscopic level. Using Western blot analysis, no co-regulation of flagella and thin aggregative fimbriae, an extracellular component of the multicellular morphotype, was observed either on plates or in standing culture. In a mutant lacking flagella and thin aggregative fimbriae, the contribution of the latter to the multicellular morphotype was dominant. We concluded that independently regulated genes can act in an additive fashion to confer a pronounced multicellular behavior.

Bacterial Adhesion↗

PubMed1981

Immunological and biochemical relationships among flagella isolated from Legionella pneumophila serogroups 1, 2, and 3.

Flagella were isolated from virulent Legionella pneumophila serogroups 1, 2, and 3. Antiserum made against purified serogroups 1 flagellin agglutinated live, flagellated serogroups 1, 2, and 3 but not heat-killed or nonflagellated bacteria. A single line of identity was seen in immunodiffusion slides between the flagella isolated from the three serogroups and antibody to flagellin isolated from serogroups 1, 2, and 3. Indirect immunoperoxidase staining showed that antibody to flagellin isolated from serogroup 1 organisms reacted with flagella on serogroup 1, 2, and 3 bacteria. Indirect immunoperoxidase staining was also showed that antibody to flagellin isolated from serogroup 1 L. pneumophila did not react with the serogroup-specific cell surface antigen, thus demonstrating that the flagella- and the serogroup-specific antigen are separate antigens. The amino acid content of the flagella from the three serogroups was essentially the same, with aspartate, glutamate, alanine, and threonine comprising 41% of the total. Thirty-five percent of the amino acids were hydrophobic, and there were not detectable amounts of cysteine, tryptophan, or tyrosine.

Agglutination Tests↗

PubMed1990

Salmonella typhimurium mutants lacking flagella or motility remain virulent in BALB/c mice.

Nonmotile flagellated (mot) and nonflagellated (fla) mutants of Salmonella typhimurium LT-2 were isolated from a collection of mutants with random Tn10-insertion mutations. Both classes of mutants were resistant to infection by the flagellotropic bacteriophage chi. The nonflagellated (fla::Tn10) mutants did not react with H antigen-specific antisera and did not possess flagella when examined by electron microscopy, and sheared-cell extracts were devoid of flagellin. The nonmotile (mot::Tn10) mutants reacted with H-specific antisera and expressed paralyzed flagella that were indistinguishable from wild-type flagella. The Tn10 insertions in strain LT-2 were mapped to loci in regions II (flh and mot) and III (fli) of the flagellar genes, and the mutations were transduced into the mouse-virulent S. typhimurium strains SR-11 and SL1344. Lack of motility reduced the ability of S. typhimurium to invade Henle cells in vitro, yet the virulence in mice of the nonmotile mutants of SR-11 and SL1344 was unaffected by the inactivity or loss of flagella. Wild-type SR-11 had a 50% lethal dose (LD50) in BALB/c mice following oral (p.o.) challenge of 2.4 x 10(4) CFU. The p.o. LD50 of the SR-11 fli-8007::Tn10 mutant was 4.5 x 10(4) CFU. The mot-8008::Tn10 mutation in SR-11 conferred paralyzed flagella and increased the p.o. LD50 in mice to 2.2 x 10(5) CFU, but this was not statistically significant. A similar increase in the p.o. LD50 was observed when the SL1344 mot-8008::Tn10 mutant was tested in mice. Wild-type SR-11 and the isogenic nonflagellated and nonmotile mutants were equally virulent in mice challenged via intraperitoneal injection.

Animals↗

PubMed2006

Flagella of Pyrococcus furiosus: multifunctional organelles, made for swimming, adhesion to various surfaces, and cell-cell contacts.

Pyrococcus furiosus ("rushing fireball") was named for the ability of this archaeal coccus to rapidly swim at its optimal growth temperature, around 100 degrees C. Early electron microscopic studies identified up to 50 cell surface appendages originating from one pole of the coccus, which have been called flagella. We have analyzed these putative motility organelles and found them to be composed primarily (>95%) of a glycoprotein that is homologous to flagellins from other archaea. Using various electron microscopic techniques, we found that these flagella can aggregate into cable-like structures, forming cell-cell connections between ca. 5% of all cells during stationary growth phase. P. furiosus cells could adhere via their flagella to carbon-coated gold grids used for electron microscopic analyses, to sand grains collected from the original habitat (Porto di Levante, Vulcano, Italy), and to various other surfaces. P. furiosus grew on surfaces in biofilm-like structures, forming microcolonies with cells interconnected by flagella and adhering to the solid supports. Therefore, we concluded that P. furiosus probably uses flagella for swimming but that the cell surface appendages also enable this archaeon to form cable-like cell-cell connections and to adhere to solid surfaces.

Archaeal Proteins↗

PubMed1971

Structure and arrangement of flagella in species of the genus Beneckea and Photobacterium fischeri.

Species of marine bacteria belonging to the genus Beneckea and strains of Photobacterium fischeri were negatively stained and examined by means of the electron microscope to determine the structure and arrangement of their flagella. All of the species of the genus Beneckea had single, polar, sheathed flagella when grown in liquid medium. When grown on solid medium, most strains of B. campbellii and B. neptuna and all strains of B. alginolytica and B. parahaemolytica had unsheathed, peritrichous flagella in addition to the single, sheathed, polar flagellum. The remaining species, B. nereida, B. pelagia, and B. natriegens, had a single, polar, sheathed flagellum when grown on solid medium. Strains of P. fischeri had sheathed flagella arranged in polar tufts. Only one group (B-2) of marine bacteria included in this study was found to have polar, unsheathed flagella.

Agar↗

PubMed1974

Antigenic difference between polar montrichous and peritrichous flagella of Vibrio parahaemolyticus.

Polar monotrichous and peritrichous flagella of Vibrio parahaemolyticus were isolated and purified separately. On hydroxylapatite column chromatography, the flagellins of polar monotrichous flagella were eluted with a higher concentration of phosphate than those of peritrichous flagella. Gel diffusion tests showed an antigenic difference between the flagellins of polar monotrichous and peritrichous flagella. Electron microscope observations on cells stained with ferritin-conjugated antibodies demonstrated that polar monotrichous and peritrichous flagella reacted specifically with antimonotrichous flagellin and antiperitrichous flagellin antisera, respectively.

Animals↗

PubMed1986

Regulation of lateral flagella gene transcription in Vibrio parahaemolyticus.

Two distinctly different organelles of locomotion are produced by Vibrio parahaemolyticus. The polar flagellum is responsible for motility in a liquid environment (swimming), and the lateral flagella enable the bacteria to move over surfaces (swarming). Synthesis of lateral flagella occurs when V. parahaemolyticus is grown on agar media but not when it is grown in liquid media. We used lux (luminescence gene) fusions to conveniently and sensitively analyze the factors which influence transcription of lateral flagella genes (laf). Transposon mini-Mu lux was used to mutagenize V. parahaemolyticus and to generate laf::lux transcriptional fusions. Mutants with insertions of mini-Mu lux in laf genes were defective in the swarming phenotype and produced light when the bacteria were propagated on agar media, but not when cells were grown in liquid media. Thus, surface-dependent expression of lateral flagella synthesis is controlled by regulation of transcription. Such fusion strains were also used to further define the environmental conditions which induce laf gene expression. Cultivation on media solidified by gelling agents other than agar also induced light production in fusion strains, as did growth on a variety of hydrophilic membrane filters suspended over liquid media. Growth at an air-surface interface was not necessary for expression since embedding the fusion strains in agar was also effective. Furthermore, induction of laf gene transcription could also be accomplished by increasing the viscosity of the liquid medium by the addition of a high-molecular-weight polymer such as polyvinylpyrrolidone. Increase in luminescence of the fusion strains was detected within 30 min of initiation of the inducing circumstance, and reversal of induction, e.g., by dilution of the viscous medium, resulted in a rapid decline in the rate of increase in luminescence. Conditions that induced luminescence in the fusion strains also induced the synthesis of lateral flagella in wild-type V. parahaemolyticus. The growth environment of the genes, and it appears that the signal that triggers laf expression is physical rather than chemical in nature. Possibilities for a sensing mechanism are discussed.

Agar↗

PubMed1992

Role of divalent cations in the subunit associations of complex flagella from Rhizobium meliloti.

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.

Calcium↗

PubMed1998

Characterization of chemotactic responses and flagella of Hyphomicrobium strain W1-1B.

Motile swarmer cells of Hyphomicrobium strain W1-1B displayed positive chemotactic responses toward methylamine, dimethylamine, and trimethylamine but did not display significant chemotactic responses towards methanol and arginine. Electron micrographs of negatively stained intact flagellar filaments indicated a novel striated surface pattern. The flagella were composed of two proteins of 39 and 41 kDa. Neither protein was a glycoprotein as determined by Schiff's staining and by enzyme immunoassay. Protein fingerprints visualized from silver-stained polyacrylamide gels and Western blots of protease-digested samples indicated that the two proteins were similar but not identical. Monoclonal antibodies prepared to the complex flagella of Rhizobium meliloti cross-reacted with the striated flagella of Hyphomicrobium strain W1-1B; however, these antibodies did not cross-react with smooth-surface flagella. These results suggest that complex and striated flagella possess homologous epitope regions.

Antibodies, Bacterial↗

PubMed1994

Investigations on the role of flagella in adhesion of Pseudomonas aeruginosa to mouse and human corneal epithelial proteins.

Antiflagellar monoclonal antibodies (MAbs) were used in an overlay assay to determine whether flagella bind to blots of mouse and human corneal epithelial proteins (CEPs). The role of carbohydrates and surface charge was also explored by preincubation of blots with periodate or neuraminidase, or flagella with monosaccharides or charged compounds, respectively. Periodate slightly decreased binding of flagella, while sialic acid inhibited binding, and the effect was dose dependent. Neuraminidase treatment of blots or incubation of flagella with a negatively, but not a positively charged compound, also blocked binding. The data suggest that flagella interact with mouse and human CEPs by electrostatic mechanisms.

Animals↗

PubMed1991

A flagella-less mutant of Borrelia burgdorferi. Structural, molecular, and in vitro functional characterization.

A nonmotile mutant of Borrelia burgdorferi, the etiologic agent of Lyme disease, was isolated and characterized. The mutant was compared with the wild-type predecessor as well as with a motile back-revertant of the same genetic background. The mutant lacked, by morphologic, biochemical, and immunologic criteria, the major structural protein of flagella, flagellin. This mutation was not associated with major DNA rearrangements or with failure of transcription. An apparent consequence of a loss of flagella was reduced ability to penetrate human endothelial cell layers in vitro. In another assessment of functional significance, the flagella-less mutant was equal if not superior to flagella-bearing, isogenic isolates when examined in an enzyme-linked immunosorbent assay for anti-B. burgdorferi antibodies in the sera of Lyme disease patients. These studies of a mutant, the first among pathogenic Borrelia spp. to be characterized, indicate that the flagellum and motility it confers play a role in B. burgdorferi's invasion of human tissues. A flagella-less B. burgdorferi may be useful as the basis of a more specific immunoassay and a vaccine for protection against Lyme disease.

Blotting, Western↗

PubMed2007

Functional genomics in Trypanosoma brucei identifies evolutionarily conserved components of motile flagella.

Cilia and flagella are highly conserved, complex organelles involved in a variety of important functions. Flagella are required for motility of several human pathogens and ciliary defects lead to a variety of fatal and debilitating human diseases. Many of the major structural components of cilia and flagella are known, but little is known about regulation of flagellar beat. Trypanosoma brucei, the causative agent of African sleeping sickness, provides an excellent model for studying flagellar motility. We have used comparative genomics to identify a core group of 50 genes unique to organisms with motile flagella. These genes, referred to as T. brucei components of motile flagella (TbCMF) include 30 novel genes, and human homologues of many of the TbCMF genes map to loci associated with human ciliary diseases. To characterize TbCMF protein function we used RNA interference to target 41 TbCMF genes. Sedimentation assays and direct observation demonstrated clear motility defects in a majority of these knockdown mutants. Epitope tagging, fluorescence localization and biochemical fractionation demonstrated flagellar localization for several TbCMF proteins. Finally, ultrastructural analysis identified a family of novel TbCMF proteins that function to maintain connections between outer doublet microtubules, suggesting that they are the first identified components of nexin links. Overall, our results provide insights into the workings of the eukaryotic flagellum, identify several novel human disease gene candidates, reveal unique aspects of the trypanosome flagellum and underscore the value of T. brucei as an experimental system for studying flagellar biology.

Amino Acid Sequence↗

PubMed1997

A multicenter vaccine trial using the Pseudomonas aeruginosa flagella vaccine IMMUNO in patients with cystic fibrosis.

Pseudomonas aeruginosa is a major pathogen in patients with cystic fibrosis (CF). In CF patients the opportunistic pathogen causes chronic pulmonary infections which are difficult to treat with antibiotics. Loss of lung function is the major cause of death in CF. Vaccination against P. aeruginosa is a possible way to prevent these infections and flagella antigens of P. aeruginosa seem to be promising vaccine candidates. In vitro and animal studies showed that flagella antigens were protective both as actively administered immunogens and in passive studies in compromised animals. Phase I studies using IMMUNO's flagella vaccines in healthy individuals revealed that, intramuscularly administered, these vaccine preparations were well tolerated, showed no adverse side effects and gave rise to high and longlasting antibody titers in the circulation of the individuals. Furthermore, immunisation with a flagella vaccine elicited specific anti-flagella antibodies not only systemically, but also in the secretory immune system of the airways. Consequently, a phase III multicenter vaccine trial using the Pseudomonas aeruginosa 5142/1210-Flagella Vaccine IMMUNO was initiated. The study design is placebo-controlled, randomized and double-blind, involving 400 CF patients without P. aeruginosa lung infection m 16 CF centers in Germany, France and Italy. The study will start in the fall of 1996 and will be carried out for 2 years.

Adult↗

PubMed2006

Tektin 4 is located on outer dense fibers, not associated with axonemal tubulins of flagella in rodent spermatozoa.

Tektins, which are thought to be the constitutive proteins of microtubules in cilia, flagella, basal bodies, and centrioles, have been reported to be involved in the stability and structural complexity of axonemal microtubules. Four types of mammalian Tektins have been reported, and at least two types of Tektins, Tektin 2 and Tektin 4, have been verified to be present in sperm flagella. To elucidate the molecular localization of Tektin 4 in flagella of rodent spermatozoa, we performed immunocytochemistry, fractionation study followed by immunoblot analysis, and immunogold electron microscopy. Confocal laser scanning microscopy and immunogold electron microscopy indicated that Tektin 4 was associated with outer dense fibers (ODFs) in both the middle and principal piece of flagella in rat and mouse spermatozoa. Tektin 4 in rat spermatozoa is completely released by 6 M urea treatment, but not extracted by 1% Triton X-100 and 0.6 M potassium thiocyanate. Pre-embedding immunoelectron microscopy demonstrated that Tektin 4 located on the abaxial (convex) surface of ODFs in flagella, not associate with axonemal microtubules. Our data strongly suggested that Tektin 4 is not associated with axonemal tubulins but an ODFs-affiliated molecule in rodent spermatozoa.

Animals↗

PubMed1995

Rigor and relaxed outer dynein arms in replicas of cryofixed motile flagella.

A method of image classification based on multivariate statistics has been developed and applied to freeze-etch images of outer dynein arms (ODAs) from cockerel sperm flagella. Demembranated flagella were cryofixed in three different nucleotide states: rigor (i.e. no added ATP); relaxed (i.e. 1 mM ATP plus vanadate); and active (i.e. 1 mM ATP). Freeze-etch replica fragments from them were coded to conceal their identities and sampled for flagella. From these a total of 6048 individual ODA images were successfully windowed and aligned, covering an angular range of 66 degrees. Each nucleotide condition produced a statistically significant ODA morphology. The relaxed and active morphologies differed only in the angulation of their heads, with the relaxed ODA favouring a more tilted position. The rigor morphology was more distinct and showed a conformational change involving a 12 nm distal shift relative to the A-tubule and highly variable heads and B-links, suggesting an ability to develop tension. Outer arms were classified by discriminant analysis as being either rigor-like, relaxed-like or active-like, and 80% of all ODAs were correctly classified. The misclassification of the remaining 20% indicated morphological heterogeneity in some of the groups. From the rigor group, 8.8% of the ODAs were misclassified as relaxed-like or active-like (i.e. non-rigor-like). It is speculated that this is a consequence of mechanochemical interactions between the B-tubules and the rigor ODAs and/or contaminating ATP remaining after demembranation. Active flagella were found to show all three morphologies, with 5.4% in the rigor conformation and 18.6% in the relaxed conformation. The finding of rigor-like and relaxed-like ODAs in flagella exposed to ATP is discussed in relation to the cross-bridge cycle.

Adenosine Triphosphate↗

PubMed2000

Role of flagellins from A and B loci in flagella formation of Halobacterium salinarum.

Haloarchaeal flagella are composed of a number of distinct flagellin proteins, specified by genes in two separate operons (A and B). The roles of these flagellins were assessed by studying mutants of H. salinarum with insertions in either the A or the B operon. Cells of the flgA- mutant produced abnormally short, curved flagella that were distributed all over the cell surface. The flgA2- strain produced straight flagella, mainly found at the poles. The flgB- mutant had flagella of the same size and spiral shape as wild-type cells, but these cells also showed unusual outgrowths, which appeared to be sacs filled with basal body-like structures. In broth cultures of this mutant, the medium accumulated flagella with basal body-like structures at their ends.

Base Sequence↗

PubMed1992

Dynein from serotonin-activated cilia and flagella: extraction characteristics and distinct sites for cAMP-dependent protein phosphorylation.

Serotonin, an activator of adenylate cyclase, stimulates motility in molluscan gill cilia and sperm flagella. To determine and compare potential targets of cAMP action, dynein was prepared from the lateral gill.cilia and sperm flagella of the mussel Mytilus edulis and the clam Spisula solidissima. In the flagella of both species, high-salt extraction removes about half of the ATPase activity, half of the alpha and beta heavy chains, and the outer arms. The dynein from both species sediments at 18-20 S, contains two or three intermediate chains, and three light chains. High-salt plus detergent removes most of the remaining dynein ATPase, alpha and beta heavy chains, and inner arms, also yielding a stable 18-20 S particle. In gill cilia of both species, high-salt extraction removes only 12-18% of the ATPase, up to 1/3 of the alpha heavy chains, an equivalent amount of beta heavy chain, and a subset of the outer arms. The dynein sediments at 18-20 S and, in Spisula, the heavy, intermediate, and light chains precisely co-sediment. High-salt plus detergent removes another 1/3 of the alpha heavy chains, an equivalent amount of beta heavy chain, and the remaining outer arms. The ATPase sediments mainly as a 13-14 S form showing considerable dissociation of co-sedimenting intermediate and light chains. The inner arms and at least half of the ciliary dynein ATPase activity remain unextractable, corresponding in mass mainly to an apparent beta heavy chain that is vanadate-cleavable. Cyclic AMP-dependent, calcium-independent phosphorylation takes place on specific dynein light chains in cilia but on only the dynein alpha heavy chain in flagella. Pre-activation of the flagella prevents subsequent addition of labeled phosphate. Phosphorylation has no effect on the steady-state ATPase properties. The single phosphate added to the flagellar alpha chain is located within the LUV1 vanadate photocleavage fragment. Considering the probable locus of the light chains and the site of the alpha heavy chain phosphorylation, both beyond the active site and toward the base of the molecule, these distinct phosphorylations may regulate dynein action by modulating arm flexibility or interaction.

Adenosine Triphosphate↗

PubMed1981

Motility of basal fragments of sea urchin sperm flagella.

Both live and reactivated sea urchin sperm flagella were broken by passage through a pipette. Distal fragments stopped, but basal fragments continued to beat. Intact flagella were about 48 micrometer long; basal fragments were about 4-20 micrometer long. Beat periods of tritonated fragments were 11% shorter than those of unbroken controls, possibly reflecting decreased viscous loading; beat periods of live fragments were 18% shorter than those of unbroken controls, possibly reflecting reduced rates of ATP consumption as well as decreased viscous loading. The undulations of basal fragments were compared with those of the basal regions of unbroken flagella, using the patterns of development of the radii and angles of basal bends. Fragments closely resembled basal regions of unbroken flagella, except that bends tended to open as they approached the distal end of a fragment, so that their radii increased more rapidly than those unbroken flagella. Fragments about 4 micrometer long contained only one bend during part of the cycle, and appeared to be straight during part of the cycle. They flipped back and forth with fairly constant angular speeds and abrupt changes in direction, so that plots of angle between their distal end and base often resembled triangular waves, although the peaks of the waveforms were often rounded. This behaviour suggests a mechanism in which sliding switches between 2 modes. Both the speed of sliding and the maximum angles attained in one direction of bending were greater than those attained in the other direction, suggesting differences between the doublets on the 2 sides of the axoneme. Sliding of the doublets continued as fast speeds as the fragments straightened, in contrast to the characteristics of some curvature-sensitive models. These flagellar fragments provide a simplified system for the study of flagellar oscillations.

Animals↗