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Journal articles on the topic 'Mobilité flagellaire'
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1
Soares, Maurilio J., Reginaldo P. Brazil, Amilcar Tanuri, and Wanderley de Souza. "Some ultrastructural aspects of Crithidia guilhermei n.sp. isolated from Phaenicia cuprina (Diptera: Calliphoridae)." Canadian Journal of Zoology 64, no. 12 (December 1, 1986): 2837–42. http://dx.doi.org/10.1139/z86-408.
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A flagellate trypanosomatid was isolated from the fly Phaenicia cuprina captured in Rio de Janeiro, Brazil. It grows well in liver infusion – trypticase medium, in the form of choanomastigotes, typical of the genus Crithidia. Morphometrical data obtained at the light microscopical level indicated that the new isolated Crithidia is smaller than Crithidia luciliae, a parasite isolated from Phaenicia sericata. Transmission electron microscopy of thin sections revealed that this trypanosomatid has a flagellar pocket divided into two compartments, one basal and the other apical, separated by a region of attachment of the flagellum to the cell body. The attachment region was characterized in freeze-fracture replicas. The flagellate has a compact kinetoplast DNA network. As in endosymbiote-containing trypanosomatids previously described, no subpellicular microtubules were seen in the regions where the mitochondria touched the plasma membrane, although no endosymbiotes were found in this flagellate. Electrophoretic mobility of six enzymes showed that the parasite could not be grouped in any of the isoenzymic pattern groups of other Crithidia spp. These observations indicate that the trypanosomatid isolated from P. cuprina is a new species of Crithidia. The flagellate is described as Crithidia guilhermei n.sp.
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Harris, J. Aaron, Yi Liu, Pinfen Yang, Peter Kner, and Karl F. Lechtreck. "Single-particle imaging reveals intraflagellar transport–independent transport and accumulation of EB1 in Chlamydomonas flagella." Molecular Biology of the Cell 27, no. 2 (January 15, 2016): 295–307. http://dx.doi.org/10.1091/mbc.e15-08-0608.
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The microtubule (MT) plus-end tracking protein EB1 is present at the tips of cilia and flagella; end-binding protein 1 (EB1) remains at the tip during flagellar shortening and in the absence of intraflagellar transport (IFT), the predominant protein transport system in flagella. To investigate how EB1 accumulates at the flagellar tip, we used in vivo imaging of fluorescent protein–tagged EB1 (EB1-FP) in Chlamydomonas reinhardtii. After photobleaching, the EB1 signal at the flagellar tip recovered within minutes, indicating an exchange with unbleached EB1 entering the flagella from the cell body. EB1 moved independent of IFT trains, and EB1-FP recovery did not require the IFT pathway. Single-particle imaging showed that EB1-FP is highly mobile along the flagellar shaft and displays a markedly reduced mobility near the flagellar tip. Individual EB1-FP particles dwelled for several seconds near the flagellar tip, suggesting the presence of stable EB1 binding sites. In simulations, the two distinct phases of EB1 mobility are sufficient to explain its accumulation at the tip. We propose that proteins uniformly distributed throughout the cytoplasm like EB1 accumulate locally by diffusion and capture; IFT, in contrast, might be required to transport proteins against cellular concentration gradients into or out of cilia.
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Ko, Minsu, and Chankyu Park. "H-NS-Dependent Regulation of Flagellar Synthesis Is Mediated by a LysR Family Protein." Journal of Bacteriology 182, no. 16 (August 15, 2000): 4670–72. http://dx.doi.org/10.1128/jb.182.16.4670-4672.2000.
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ABSTRACT H-NS regulates the flagellar master operon (flhDC) and thus is necessary for flagellation of Escherichia coli. However, the molecular mechanism of its regulation has remained unknown. Genetic screening of a transposon insertion abolishing the H-NS effect revealed a previously unidentified gene, namedhdfR, encoding a LysR family protein. Binding of purified HdfR to the flhDC promoter was demonstrated by a DNA mobility shift assay, indicating that HdfR is a transcriptional regulator for the flagellar master operon. Furthermore, the expression of the hdfR gene was shown to be negatively regulated by H-NS.
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Correa, Nidia E., and Karl E. Klose. "Characterization of Enhancer Binding by the Vibrio cholerae Flagellar Regulatory Protein FlrC." Journal of Bacteriology 187, no. 9 (May 1, 2005): 3158–70. http://dx.doi.org/10.1128/jb.187.9.3158-3170.2005.
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ABSTRACT The human pathogen Vibrio cholerae is a highly motile organism by virtue of a polar flagellum, and motility has been inferred to be an important aspect of virulence. It has previously been demonstrated that the σ54-dependent activator FlrC is necessary for both flagellar synthesis and for enhanced intestinal colonization. In order to characterize FlrC binding, we analyzed two FlrC-dependent promoters, the highly transcribed flaA promoter and the weakly transcribed flgK promoter, utilizing transcriptional lacZ fusions, mobility shift assays, and DNase I footprinting. Promoter fusion studies showed that the smallest fragment with wild-type transcriptional activity for flaAp was from positions −54 to +137 with respect to the start site, and from −63 to +144 for flgKp. Gel mobility shift assays indicated that FlrC binds to a fragment containing the region from positions +24 to +95 in the flaAp, and DNase I footprinting identified a protected region between positions +24 and +85. Mobility shift and DNase I footprinting indicated weak binding of FlrC to a region downstream of the flgKp transcription start site. These results demonstrate a relatively novel σ54-dependent promoter architecture, with the activator FlrC binding downstream of the σ54-dependent transcription start sites. When the FlrC binding site(s) in the flaA promoter was moved a large distance (285 bp) upstream of the transcription start site of either flaAp or flgKp, high levels of FlrC-dependent transcription resulted, indicating that this binding region functions as an enhancer element. In contrast, the relatively weak FlrC binding site(s) in the flgK promoter failed to function as an enhancer element at either promoter, suggesting that FlrC binding strength contributes to enhancer activity. Our results suggest that the differences in FlrC binding to various flagellar promoters results in the differences in transcription levels that mirror the relative requirement for the flagellar components within the flagellum.
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Teplitski, Max, Robert I. Goodier, and Brian M. M. Ahmer. "Pathways Leading from BarA/SirA to Motility andVirulence Gene Expression inSalmonella." Journal of Bacteriology 185, no. 24 (December 15, 2003): 7257–65. http://dx.doi.org/10.1128/jb.185.24.7257-7265.2003.
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ABSTRACT The barA and sirA genes of Salmonella enterica serovar Typhimurium encode a two-component sensor kinase and a response regulator, respectively. This system increases the expression of virulence genes and decreases the expression of motility genes. In this study, we examined the pathways by which SirA affects these genes. We found that the master regulator of flagellar genes, flhDC, had a positive regulatory effect on the primary regulator of intestinal virulence determinants, hilA, but that hilA had no effect on flhDC. SirA was able to repress flhDC in a hilA mutant and activate hilA in an flhDC mutant. Therefore, although the flhDC and hilA regulatory cascades interact, sirA affects each of them independently. A form of BarA lacking the two N-terminal membrane-spanning domains, BarA198, autophosphorylates in the presence of ATP and transfers the phosphate to purified SirA. Phosphorylated SirA was found to directly bind the hilA and hilC promoters in gel mobility shift assays but not the flhD, fliA, hilD, and invF promoters. Given that the CsrA/csrB system is known to directly affect flagellar gene expression, we tested the hypothesis that SirA affects flagellar gene expression indirectly by regulating csrA or csrB. The sirA gene did not regulate csrA but did activate csrB expression. Consistent with these results, phosphorylated SirA was found to directly bind the csrB promoter but not the csrA promoter. We propose a model in which SirA directly activates virulence expression via hilA and hilC while repressing the flagellar regulon indirectly via csrB.
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Soscia, Chantal, Abderrahman Hachani, Alain Bernadac, Alain Filloux, and Sophie Bleves. "Cross Talk between Type III Secretion and Flagellar Assembly Systems in Pseudomonas aeruginosa." Journal of Bacteriology 189, no. 8 (February 16, 2007): 3124–32. http://dx.doi.org/10.1128/jb.01677-06.
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ABSTRACT Pseudomonas aeruginosa cytotoxicity is linked to a type III secretion system (T3SS) that delivers effectors into the host cell. We show here that a negative cross-control exists between T3SS and flagellar assembly. We observed that, in a strain lacking flagella, T3SS gene expression, effector secretion, and cytotoxicity were increased. Conversely, we revealed that flagellar-gene expression and motility were decreased in a strain overproducing ExsA, the T3SS master regulator. Interestingly, a nonmotile strain lacking the flagellar filament (ΔfliC) presented a hyperefficient T3SS and a nonmotile strain assembling flagella (ΔmotAB) did not. More intriguingly, a strain lacking motCD genes is a flagellated strain with a slight defect in swimming. However, in this strain, T3SS gene expression was up-regulated. These results suggest that flagellar assembly and/or mobility antagonizes the T3SS and that a negative cross talk exists between these two systems. An illustration of this is the visualization by electron microscopy of T3SS needles in a nonmotile P. aeruginosa strain, needles which otherwise are not detected. The molecular basis of the cross talk is complex and remains to be elucidated, but proteins like MotCD might have a crucial role in signaling between the two processes. In addition, we found that the GacA response regulator negatively affects the T3SS. In a gacA mutant, the T3SS effector ExoS is hypersecreted. Strikingly, GacA was previously reported as a positive regulator for motility. Globally, our data document the idea that some virulence factors are coordinately but inversely regulated, depending on the bacterial colonization phase and infection types.
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Jian, Huahua, Guanpeng Xu, Yingbao Gai, Jun Xu, and Xiang Xiao. "The Histone-Like Nucleoid Structuring Protein (H-NS) Is a Negative Regulator of the Lateral Flagellar System in the Deep-Sea Bacterium Shewanella piezotolerans WP3." Applied and Environmental Microbiology 82, no. 8 (February 12, 2016): 2388–98. http://dx.doi.org/10.1128/aem.00297-16.
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ABSTRACTAlthough the histone-like nucleoid structuring protein (H-NS) is well known for its involvement in the adaptation of mesophilic bacteria, such asEscherichia coli, to cold environments and high-pressure stress, an understanding of the role of H-NS in the cold-adapted benthic microorganisms that live in the deep-sea ecosystem, which covers approximately 60% of the earth's surface, is still lacking. In this study, we characterized the function of H-NS inShewanella piezotoleransWP3, which was isolated from West Pacific sediment at a depth of 1,914 m. Anhnsgene deletion mutant (WP3Δhns) was constructed, and comparative whole-genome microarray analysis was performed. H-NS had a significant influence (fold change, >2) on the expression of a variety of WP3 genes (274 and 280 genes were upregulated and downregulated, respectively), particularly genes related to energy production and conversion. Notably, WP3Δhnsexhibited higher expression levels of lateral flagellar genes than WP3 and showed enhanced swarming motility and lateral flagellar production compared to those of WP3. The DNA gel mobility shift experiment showed that H-NS bound specifically to the promoter of lateral flagellar genes. Moreover, the high-affinity binding sequences of H-NS were identified by DNase I protection footprinting, and the results support the “binding and spreading” model for H-NS functioning. To our knowledge, this is the first attempt to characterize the function of the universal regulator H-NS in a deep-sea bacterium. Our data revealed that H-NS has a novel function as a repressor of the expression of genes related to the energy-consuming secondary flagellar system and to swarming motility.
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Williams, B. D., D. R. Mitchell, and J. L. Rosenbaum. "Molecular cloning and expression of flagellar radial spoke and dynein genes of Chlamydomonas." Journal of Cell Biology 103, no. 1 (July 1, 1986): 1–11. http://dx.doi.org/10.1083/jcb.103.1.1.
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Several flagellar dynein ATPase and radial spokehead genes have been isolated from a Chlamydomonas genomic expression library in lambda gt11. The library was probed with polyclonal and monoclonal antibodies raised against purified flagellar polypeptides, and recombinant phage giving positive signals were cloned. In vitro translation of mRNAs hybrid-selected by the cloned sequences from whole cell RNA provided confirmation of identity for three of the four clones. Evidence supporting the identification of the fourth, which encodes a dynein heavy chain, was provided by antibody selection; the fusion protein produced by this clone selected heavy chain-specific antibodies from a complex polyclonal antiserum recognizing many dynein determinants. One of the radial spoke sequences isolated here is of particular interest because it encodes the wild-type allele of a locus which was defined previously by temperature-sensitive paralyzed flagella mutation pf-26ts (Huang, B., G. Piperno, Z. Ramanis, and D. J. L. Luck, 1981, J. Cell Biol., 88:80-88). The cloned sequence was used to hybrid-select mRNA from mutant pf-26ts cells, and when translated in vitro, the selected mRNA produced a mutant spokehead polypeptide with an altered electrophoretic mobility. This confirms that the pf-26ts mutation alters the primary structure of a radial spokehead polypeptide. To quantify spokehead and dynein mRNAs during flagellar regeneration, all of the cloned sequences were used as hybridization probes in RNA dot experiments. Levels increased rapidly and coordinately after deflagellation, peaked 3-10-fold above nondeflagellated controls, and then returned to control values within 2 h. This accumulation pattern was similar to that of flagellar alpha-tubulin mRNA.
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Wen, Yi, Jing Feng, David R. Scott, Elizabeth A. Marcus, and George Sachs. "The pH-Responsive Regulon of HP0244 (FlgS), the Cytoplasmic Histidine Kinase of Helicobacter pylori." Journal of Bacteriology 191, no. 2 (October 31, 2008): 449–60. http://dx.doi.org/10.1128/jb.01219-08.
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ABSTRACT Helicobacter pylori colonizes the acidic gastric environment, in contrast to all other neutralophiles, whose acid resistance and tolerance responses allow only gastric transit. This acid adaptation is dependent on regulation of gene expression in response to pH changes in the periplasm and cytoplasm. The cytoplasmic histidine kinase, HP0244, which until now was thought only to regulate flagellar gene expression via its cognate response regulator, HP0703, was found to generate a response to declining medium pH. Although not required for survival at pH 4.5, HP0244 is required for survival at pH 2.5 with 10 mM urea after 30 min. Transcriptional profiling of a HP0244 deletion mutant grown at pH 7.4 confirmed the contribution of HP0244 to σ54 activation via HP0703 to coordinate flagellar biosynthesis by a pH-independent regulon that includes 14 flagellar genes. Microarray analysis of cells grown at pH 4.5 without urea revealed an additional 22 genes, including 4 acid acclimation genes (ureA, ureB, ureI, and amiE) that are positively regulated by HP0244. Additionally, 86 differentially expressed genes, including 3 acid acclimation genes (ureF, rocF [arginase], and ansB [asparaginase]), were found in cells grown at pH 2.5 with 30 mM urea. Hence, HP0244 has, in addition to the pH-independent flagellar regulon, a pH-dependent regulon, which allows adaptation to a wider range of environmental acid conditions. An acid survival study using an HP0703 mutant and an electrophoretic mobility shift assay with in vitro-phosphorylated HP0703 showed that HP0703 does not contribute to acid survival and does not bind to the promoter regions of several genes in the HP0244 pH-dependent regulon, suggesting that there is a pathway outside the HP0703 regulon which transduces the acid-responsive signal sensed by HP0244.
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Kim, Yun-Kyeong, and Linda L. McCarter. "ScrG, a GGDEF-EAL Protein, Participates in Regulating Swarming and Sticking in Vibrio parahaemolyticus." Journal of Bacteriology 189, no. 11 (March 30, 2007): 4094–107. http://dx.doi.org/10.1128/jb.01510-06.
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ABSTRACT In this work, we describe a new gene controlling lateral flagellar gene expression. The gene encodes ScrG, a protein containing GGDEF and EAL domains. This is the second GGDEF-EAL-encoding locus determined to be involved in the regulation of swarming: the first was previously characterized and named scrABC (for “swarming and capsular polysaccharide regulation”). GGDEF and EAL domain-containing proteins participate in the synthesis and degradation of the nucleotide signal cyclic di-GMP (c-di-GMP) in many bacteria. Overexpression of scrG was sufficient to induce lateral flagellar gene expression in liquid, decrease biofilm formation, decrease cps gene expression, and suppress the ΔscrABC phenotype. Removal of its EAL domain reversed ScrG activity, converting ScrG to an inhibitor of swarming and activator of cps expression. Overexpression of scrG decreased the intensity of a 32P-labeled nucleotide spot comigrating with c-di-GMP standard, whereas overexpression of scrG Δ EAL enhanced the intensity of the spot. Mutants with defects in scrG showed altered swarming and lateral flagellin production and colony morphology (but not swimming motility); furthermore, mutation of two GGDEF-EAL-encoding loci (scrG and scrABC) produced cumulative effects on swarming, lateral flagellar gene expression, lateral flagellin production and colony morphology. Mutant analysis supports the assignment of the primary in vivo activity of ScrG to acting as a phosphodiesterase. The data are consistent with a model in which multiple GGDEF-EAL proteins can influence the cellular nucleotide pool: a low concentration of c-di-GMP favors surface mobility, whereas high levels of this nucleotide promote a more adhesive Vibrio parahaemolyticus cell type.
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Hu, Yangbo, Yao Wang, Lisha Ding, Pei Lu, Steve Atkinson, and Shiyun Chen. "Positive regulation of flhDC expression by OmpR in Yersinia pseudotuberculosis." Microbiology 155, no. 11 (November 1, 2009): 3622–31. http://dx.doi.org/10.1099/mic.0.030908-0.
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OmpR has been demonstrated to negatively regulate the expression of the flagellar master operon flhDC in a wide variety of bacterial species. Here we report the positive regulation of flhDC expression by OmpR in Yersinia pseudotuberculosis. A σ 70-dependent promoter was identified by primer extension analysis and an active region with two conserved OmpR-binding sites around the flhDC promoter was confirmed. To confirm the regulation of flhDC expression by OmpR, flhDC as well as the downstream flagellar genes fliA, flgD, flgA, flgM, fliC and flaA were fused to lacZ, and decreased expression of all these genes in an ompR mutant (ΔompR) was detected. Furthermore, ΔompR was defective in bacterial motility and flagella synthesis. This defect was due to the low level of expression of flhDC in ΔompR since overproduction of FlhDC in ΔompR restored bacterial motility. The importance of two conserved OmpR-binding sites around the flhDC promoter region in the regulation of flhDC expression by OmpR was demonstrated by the fact that mutation of either one or both sites significantly decreased the promoter activity in the wild-type but not in ΔompR. The binding of OmpR to these two sites was also demonstrated by DNA mobility shift assay. The possible mechanism underlying this positive regulation in Y. pseudotuberculosis is discussed. To our knowledge, this is the first report to demonstrate that OmpR positively regulates flhDC expression.
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Bergara, F., C. Ibarra, J. Iwamasa, J. C. Patarroyo, R. Aguilera, and L. M. Márquez-Magaña. "CodY Is a Nutritional Repressor of Flagellar Gene Expression in Bacillus subtilis." Journal of Bacteriology 185, no. 10 (May 15, 2003): 3118–26. http://dx.doi.org/10.1128/jb.185.10.3118-3126.2003.
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ABSTRACT Expression of the σD-dependent flagellin gene, hag, is repressed by the CodY protein in nutrient-rich environments. Analysis of a codY mutant bearing a hag-lacZ reporter suggests that the availability of amino acids in the environment is the specific signal that triggers this repression. Further, hag-lacZ expression appears to be sensitive to intracellular GTP levels, as demonstrated by increased expression upon addition of decoyinine. This result is consistent with the postulate that the availability of amino acids in the environment effects intracellular GTP levels through the stringent response. However, the levels of hag-lacZ measured upon the addition of subsets of amino acids suggest an additional mechanism(s). CodY is a DNA binding protein that could repress flagellin expression directly by binding to the hag promoter region, or indirectly by binding to the fla/che promoter region that governs expression of the σD transcriptional activator required for hag gene expression. Using an electrophoretic mobility shift assay, we have demonstrated that purified CodY protein binds specifically to both the hag and fla/che promoter fragments. Additionally, CodY acts as a nutritional repressor of transcription from the fla/che promoter region that contains two functional promoters. CodY binds to both the σD- and σA-dependent promoters in this region, as demonstrated by DNase I footprint analyses. Footprint analyses of the hag gene demonstrated that CodY binds downstream of its σD-dependent promoter. Taken together, these results identify new members of the CodY regulon that encode motility functions in Bacillus subtilis and are controlled by the σD alternate sigma factor.
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Davidge, J. A. "Trypanosome IFT mutants provide insight into the motor location for mobility of the flagella connector and flagellar membrane formation." Journal of Cell Science 119, no. 19 (October 1, 2006): 3935–43. http://dx.doi.org/10.1242/jcs.03203.
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Liao, Sumei, Aihua Sun, David M. Ojcius, Senlin Wu, Jinfang Zhao, and Jie Yan. "Inactivation of the fliY gene encoding a flagellar motor switch protein attenuates mobility and virulence of Leptospira interrogans strain Lai." BMC Microbiology 9, no. 1 (2009): 253. http://dx.doi.org/10.1186/1471-2180-9-253.
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Chun, Heejin, Okhee Choi, Eunhye Goo, Nayeon Kim, Hongsup Kim, Yongsung Kang, Jinwoo Kim, Jae Sun Moon, and Ingyu Hwang. "The Quorum Sensing-Dependent Gene katG of Burkholderia glumae Is Important for Protection from Visible Light." Journal of Bacteriology 191, no. 13 (April 24, 2009): 4152–57. http://dx.doi.org/10.1128/jb.00227-09.
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ABSTRACT Quorum sensing (QS) plays important roles in the pathogenicity of Burkholderia glumae, the causative agent of bacterial rice grain rot. We determined how QS is involved in catalase expression in B. glumae. The QS-defective mutant of B. glumae exhibited less catalase activity than wild-type B. glumae. A β-glucuronidase assay of a katG::Tn3-gusA78 reporter fusion protein revealed that katG expression is under the control of QS. Furthermore, katG expression was upregulated by QsmR, a transcriptional activator for flagellar-gene expression that is regulated by QS. A gel mobility shift assay confirmed that QsmR directly activates katG expression. The katG mutant produced toxoflavin but exhibited less severe disease than BGR1 on rice panicles. Under visible light conditions and a photon flux density of 61.6 μmol−1 m−2, the survival rate of the katG mutant was 105-fold lower than that of BGR1. This suggests that KatG is a major catalase that protects bacterial cells from visible light, which probably results in less severe disease caused by the katG mutant.
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Šimkus, Remigijus, Rita Meškienė, Agota Aučynaitė, Žilvinas Ledas, Romas Baronas, and Rolandas Meškys. "Phoretic interactions and oscillations in active suspensions of growing Escherichia coli." Royal Society Open Science 5, no. 5 (May 2018): 180008. http://dx.doi.org/10.1098/rsos.180008.
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Bioluminescence imaging experiments were carried out to characterize spatio-temporal patterns of bacterial self-organization in active suspensions (cultures) of bioluminescent Escherichia coli and its mutants. An analysis of the effects of mutations shows that spatio-temporal patterns formed in standard microtitre plates are not related to the chemotaxis system of bacteria. In fact, these patterns are strongly dependent on the properties of mutants that characterize them as self-phoretic (non-flagellar) swimmers. In particular, the observed patterns are essentially dependent on the efficiency of proton translocation across membranes and the smoothness of the cell surface. These characteristics can be associated, respectively, with the surface activity and the phoretic mobility of a colloidal swimmer. An analysis of the experimental data together with mathematical modelling of pattern formation suggests the following: (1) pattern-forming processes can be described by Keller–Segel-type models of chemotaxis with logistic cell kinetics; (2) active cells can be seen as biochemical oscillators that exhibit phoretic drift and alignment; and (3) the spatio-temporal patterns in a suspension of growing E. coli form due to phoretic interactions between oscillating cells of high metabolic activity.
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Yokota, E., and I. Mabuchi. "Isolation and characterization of a novel dynein that contains C and A heavy chains from sea urchin sperm flagellar axonemes." Journal of Cell Science 107, no. 2 (February 1, 1994): 345–51. http://dx.doi.org/10.1242/jcs.107.2.345.
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A novel dynein (C/A dynein), which is composed of C and A heavy chains, two intermediate chains and several light chains, was isolated from sea urchin sperm flagella. The C/A dynein was released by the treatment with 0.7 M NaCl plus 5 mM ATP from the axonemes depleted of outer arm 21 S dynein. Sedimentation coefficient of this dynein was estimated by sucrose density gradient centrifugation to be 22–23 S. The C/A dynein particle appeared to be composed of three distinct domains; two globular head domains and one rod domain as seen by negative staining electron microscopy. The mobility of ‘A’ heavy chain of C/A dynein on SDS-gel electrophoresis was similar to that of A heavy chains (A alpha and A beta) of 21 S dynein. However, UV-cleavage patterns of C and A heavy chains of C/A dynein were different from those of A heavy chains of 21 S dynein. Furthermore, an antiserum raised against A heavy chain of C/A dynein did not crossreact with A heavy chains of 21 S dynein. Under the conditions in which the C/A dynein was released, some of inner arms were removed concomitantly from axonemes as observed by electron microscopy. These results suggested that C/A dynein is a component of the inner arms.
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Beaber, John W., Bianca Hochhut, and Matthew K. Waldor. "Genomic and Functional Analyses of SXT, an Integrating Antibiotic Resistance Gene Transfer Element Derived from Vibrio cholerae." Journal of Bacteriology 184, no. 15 (August 1, 2002): 4259–69. http://dx.doi.org/10.1128/jb.184.15.4259-4269.2002.
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ABSTRACT SXT is representative of a family of conjugative-transposon-like mobile genetic elements that encode multiple antibiotic resistance genes. In recent years, SXT-related conjugative, self-transmissible integrating elements have become widespread in Asian Vibrio cholerae. We have determined the 100-kb DNA sequence of SXT. This element appears to be a chimera composed of transposon-associated antibiotic resistance genes linked to a variety of plasmid- and phage-related genes, as well as to many genes from unknown sources. We constructed a nearly comprehensive set of deletions through the use of the one-step chromosomal gene inactivation technique to identify SXT genes involved in conjugative transfer and chromosomal excision. SXT, unlike other conjugative transposons, utilizes a conjugation system related to that encoded by the F plasmid. More than half of the SXT genome, including the composite transposon-like structure that contains its antibiotic resistance genes, was not required for its mobility. Two SXT loci, designated setC and setD, whose predicted amino acid sequences were similar to those of the flagellar regulators FlhC and FlhD, were found to encode regulators that activate the transcription of genes required for SXT excision and transfer. Another locus, designated setR, whose gene product bears similarity to lambdoid phage CI repressors, also appears to regulate SXT gene expression.
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Tart, Anne H., Michael J. Blanks, and Daniel J. Wozniak. "The AlgT-Dependent Transcriptional Regulator AmrZ (AlgZ) Inhibits Flagellum Biosynthesis in Mucoid, Nonmotile Pseudomonas aeruginosa Cystic Fibrosis Isolates." Journal of Bacteriology 188, no. 18 (September 15, 2006): 6483–89. http://dx.doi.org/10.1128/jb.00636-06.
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ABSTRACT Pseudomonas aeruginosa is a microorganism associated with the disease cystic fibrosis. While environmental P. aeruginosa strains are generally nonmucoid and motile, isolates recovered from the cystic fibrosis lung frequently display a mucoid, nonmotile phenotype. This phenotypic conversion is mediated by the alternative sigma factor AlgT. Previous work has shown that repression of fleQ by AlgT accounts for the loss of flagellum biosynthesis in these strains. Here, we elucidate the mechanism involved in the AlgT-mediated control of fleQ. Electrophoretic mobility shift assays using purified AlgT and extracts derived from isogenic AlgT+ and AlgT− strains revealed that AlgT inhibits fleQ indirectly. We observed that the AlgT-dependent transcriptional regulator AmrZ interacts directly with the fleQ promoter. To determine whether AmrZ functions as a repressor of fleQ, we mutated amrZ in the mucoid, nonmotile P. aeruginosa strain FRD1. Unlike the parental strain, the amrZ mutant was nonmucoid and motile. Complementation of the mutant with amrZ restored the mucoid, nonmotile phenotype. Thus, our data show that AlgT inhibits flagellum biosynthesis in mucoid, nonmotile P. aeruginosa cystic fibrosis isolates by promoting expression of AmrZ, which subsequently represses fleQ. Since fleQ directly or indirectly controls the expression of almost all flagellar genes, its repression ultimately leads to the loss of flagellum biosynthesis.
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Rodriguez-Zaragoza, Salvador, Einav Mayzlish, and Yosef Steinberger. "Vertical Distribution of the Free-Living Amoeba Population in Soil under Desert Shrubs in the Negev Desert, Israel." Applied and Environmental Microbiology 71, no. 4 (April 2005): 2053–60. http://dx.doi.org/10.1128/aem.71.4.2053-2060.2005.
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ABSTRACT A field study was designed to examine the effect of desert shrubs on the dynamics of free-living amoebae in arid soil. Soil samples from 0- to 50-cm depths were collected at 10-cm intervals in each of the four seasons. The vertical distributions of the four main morphological types of amoebae, grouped according to their mobility, and of small flagellate populations were measured under the canopies of Hammada scoparia and Atriplex halimus, shrubs belonging to the chloride-absorbing xerohalophytes. The result obtained from the field study demonstrated that the total number of protozoa was significantly higher during the wet seasons (winter and spring) than during the dry seasons. The protozoan population was more diverse under the canopy of H. scoparia during the wet seasons, reaching 8,000 individuals per 1 g of dry soil, whereas during the dry seasons, the populations were higher under the canopy of A. halimus, with a mean of 250 individuals. The protozoan population in the deeper layers (40 to 50 cm) was found to be as active as that in the upper layers, demonstrating that, in the desert, soil columns below 20 cm are fertile and worth studying. The type 1 amoebae (e.g., Acanthamoeba and Filamoeba spp.) were the most abundant throughout the study period, and their numbers were significantly higher than those of the other amoeba types.
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Askoura, Momen, Sabina Sarvan, Jean-François Couture, and Alain Stintzi. "The Campylobacter jejuni Ferric Uptake Regulator Promotes Acid Survival and Cross-Protection against Oxidative Stress." Infection and Immunity 84, no. 5 (February 16, 2016): 1287–300. http://dx.doi.org/10.1128/iai.01377-15.
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Campylobacter jejuniis a prevalent cause of bacterial gastroenteritis in humans worldwide. The mechanisms by whichC. jejunisurvives stomach acidity remain undefined. In the present study, we demonstrated that theC. jejuniferric uptake regulator (Fur) plays an important role inC. jejuniacid survival and acid-induced cross-protection against oxidative stress. AC. jejuniΔfurmutant was more sensitive to acid than the wild-type strain. Profiling of the acid stimulon of theC. jejuniΔfurmutant allowed us to uncover Fur-regulated genes under acidic conditions. In particular, Fur was found to upregulate genes involved in flagellar and cell envelope biogenesis upon acid stress, and mutants with deletions of these genes were found to be defective in surviving acid stress. Interestingly, prior acid exposure ofC. jejunicross-protected against oxidative stress in a catalase (KatA)- and Fur-dependent manner. Western blotting and reverse transcription-quantitative PCR revealed increased expression of KatA upon acid stress. Electrophoretic mobility shift assays (EMSAs) demonstrated that the binding affinity between Fur and thekatApromoter is reducedin vitrounder conditions of low pH, rationalizing the higher levels of expression ofkatAunder acidic conditions. Strikingly, the Δfurmutant exhibited reduced virulence in both human epithelial cells and theGalleria mellonellainfection model. Altogether, this is the first study showing that, in addition to its role in iron metabolism, Fur is an important regulator ofC. jejuniacid responses and this function cross-protects against oxidative stress. Moreover, our results clearly demonstrate Fur's important role inC. jejunipathogenesis.
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Amati, Giuseppe, Paola Bisicchia, and Alessandro Galizzi. "DegU-P Represses Expression of the Motility fla-che Operon in Bacillus subtilis." Journal of Bacteriology 186, no. 18 (September 15, 2004): 6003–14. http://dx.doi.org/10.1128/jb.186.18.6003-6014.2004.
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ABSTRACT Bacillus subtilis implements several adaptive strategies to cope with nutrient limitation experienced at the end of exponential growth. The DegS-DegU two-component system is part of the network involved in the regulation of postexponential responses, such as competence development, the production of exoenzymes, and motility. The degU32(Hy) mutation extends the half-life of the phosphorylated form of DegU (DegU-P); this in turn increases the production of alkaline protease, levan-sucrase, and other exoenzymes and inhibits motility and the production of flagella. The expression of the flagellum-specific sigma factor SigD, of the flagellin gene hag, and of the fla-che operon is strongly reduced in a degU32(Hy) genetic background. To investigate the mechanism of action of DegU-P on motility, we isolated mutants of degU32(Hy) that completely suppressed the motility deficiency. The mutations were genetically mapped and characterized by PCR and sequencing. Most of the mutations were found to delete a transcriptional termination signal upstream of the main flagellar operon, fla-che, thus allowing transcriptional readthrough from the cod operon. Two additional mutations improved the σA-dependent promoter sequence of the fla-che operon. Using an electrophoretic mobility shift assay, we have demonstrated that purified DegU binds specifically to the PA promoter region of the fla-che operon. The data suggest that DegU represses transcription of the fla-che operon, and they indicate a central role of the operon in regulating the synthesis and assembly of flagella.
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Iyoda, Sunao, Naoko Honda, Takehito Saitoh, Ken Shimuta, Jun Terajima, Haruo Watanabe, and Makoto Ohnishi. "Coordinate Control of the Locus of Enterocyte Effacement and Enterohemolysin Genes by Multiple Common Virulence Regulators in Enterohemorrhagic Escherichia coli." Infection and Immunity 79, no. 11 (August 15, 2011): 4628–37. http://dx.doi.org/10.1128/iai.05023-11.
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ABSTRACTThe locus of enterocyte effacement (LEE) pathogenicity island is required for the intimate adhesion of enterohemorrhagicEscherichia coli(EHEC) to the intestinal epithelial cells. GrlR and GrlA are LEE-encoded negative and positive regulators, respectively. The interaction of these two regulators is important for controlling the transcription of LEE genes through Ler, a LEE-encoded central activator for the LEE. The GrlR-GrlA regulatory system controls not only LEE but also the expression of the flagellar and enterohemolysin (Ehx) genes in EHEC. Since Ehx levels were markedly induced in agrlRmutant but not in agrlR grlAdouble mutant and significantly increased by overexpression of GrlA in alermutant, GrlA is responsible for this regulation (T. Saitoh et al., J. Bacteriol.190:4822-4830, 2008). In this study, additional investigations of the regulation ofehxgene expression determined that Ler also acts as an activator for Ehx expression without requiring GrlA function. We recently reported that the LysR-type regulator LrhA positively controls LEE expression (N. Honda et al., Mol. Microbiol.74:1393-1411, 2009). The hemolytic activity of thelrhAmutant strain of EHEC was lower than that of the wild-type strain, and LrhA markedly inducedehxtranscription in anE. coliK-12 strain, suggesting that LrhA also activates the transcription ofehxwithout GrlA and Ler. Gel mobility shift assays demonstrated that Ler and LrhA directly bind to the regulatory region ofehxC. Together, these results indicate that transcription ofehxis positively regulated by Ler, GrlA, and LrhA, which all act as positive regulators for LEE expression.
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Li, Qing-Mei, Ying-Li Zhou, Zhan-Fei Wei, and Yong Wang. "Phylogenomic Insights into Distribution and Adaptation of Bdellovibrionota in Marine Waters." Microorganisms 9, no. 4 (April 3, 2021): 757. http://dx.doi.org/10.3390/microorganisms9040757.
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Bdellovibrionota is composed of obligate predators that can consume some Gram-negative bacteria inhabiting various environments. However, whether genomic traits influence their distribution and marine adaptation remains to be answered. In this study, we performed phylogenomics and comparative genomics studies using 132 Bdellovibrionota genomes along with five metagenome-assembled genomes (MAGs) from deep sea zones. Four phylogenetic groups, Oligoflexia, Bdello-group1, Bdello-group2 and Bacteriovoracia, were revealed by constructing a phylogenetic tree, of which 53.84% of Bdello-group2 and 48.94% of Bacteriovoracia were derived from the ocean. Bacteriovoracia was more prevalent in deep sea zones, whereas Bdello-group2 was largely distributed in the epipelagic zone. Metabolic reconstruction indicated that genes involved in chemotaxis, flagellar (mobility), type II secretion system, ATP-binding cassette (ABC) transporters and penicillin-binding protein were necessary for the predatory lifestyle of Bdellovibrionota. Genes involved in glycerol metabolism, hydrogen peroxide (H2O2) degradation, cell wall recycling and peptide utilization were ubiquitously present in Bdellovibrionota genomes. Comparative genomics between marine and non-marine Bdellovibrionota demonstrated that betaine as an osmoprotectant is probably widely used by marine Bdellovibrionota, and all the marine genomes have a number of genes for adaptation to marine environments. The genes encoding chitinase and chitin-binding protein were identified for the first time in Oligoflexia, which implied that Oligoflexia may prey on a wider spectrum of microbes. This study expands our knowledge on adaption strategies of Bdellovibrionota inhabiting deep seas and the potential usage of Oligoflexia for biological control.
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Sergeant, Martin, Laura Baxter, Paul Jarrett, Eve Shaw, Margaret Ousley, Craig Winstanley, and J. Alun W. Morgan. "Identification, Typing, and Insecticidal Activity of Xenorhabdus Isolates from Entomopathogenic Nematodes in United Kingdom Soil and Characterization of the xpt Toxin Loci." Applied and Environmental Microbiology 72, no. 9 (September 2006): 5895–907. http://dx.doi.org/10.1128/aem.00217-06.
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ABSTRACT Xenorhabdus strains from entomopathogenic nematodes isolated from United Kingdom soils by using the insect bait entrapment method were characterized by partial sequencing of the 16S rRNA gene, four housekeeping genes (asd, ompR, recA, and serC) and the flagellin gene (fliC). Most strains (191/197) were found to have genes with greatest similarity to those of Xenorhabdus bovienii, and the remaining six strains had genes most similar to those of Xenorhabdus nematophila. Generally, 16S rRNA sequences and the sequence types based on housekeeping genes were in agreement, with a few notable exceptions. Statistical analysis implied that recombination had occurred at the serC locus and that moderate amounts of interallele recombination had also taken place. Surprisingly, the fliC locus contained a highly variable central region, even though insects lack an adaptive immune response, which is thought to drive flagellar variation in pathogens of higher organisms. All the X. nematophila strains exhibited a consistent pattern of insecticidal activity, and all contained the insecticidal toxin genes xptA1A2B1C1, which were present on a pathogenicity island (PAI). The PAIs were similar among the X. nematophila strains, except for partial deletions of a peptide synthetase gene and the presence of insertion sequences. Comparison of the PAI locus with that of X. bovienii suggested that the PAI integrated into the genome first and then acquired the xpt genes. The independent mobility of xpt genes was further supported by the presence of xpt genes in X. bovienii strain I73 on a type 2 transposon structure and by the variable patterns of insecticidal activity in X. bovienii isolates, even among closely related strains.
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Ferrándiz, Maria-José, Keith Bishop, Paul Williams, and Helen Withers. "HosA, a Member of the SlyA Family, Regulates Motility in Enteropathogenic Escherichia coli." Infection and Immunity 73, no. 3 (March 2005): 1684–94. http://dx.doi.org/10.1128/iai.73.3.1684-1694.2005.
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ABSTRACT In enteropathogenic and enterohemorraghic Escherichia coli (EPEC and EHEC), two members of the SlyA family of transcriptional regulators have been identified as SlyA. Western blot analysis of the wild type and the corresponding hosA and slyA deletion mutants indicated that SlyA and HosA are distinct proteins whose expression is not interdependent. Of 27 different E. coli strains (EPEC, EHEC, enteroinvasive, enteroaggregative, uropathogenic, and commensal) examined, 14 were positive for both genes and proteins. To investigate hosA expression, a hosA::luxCDABE reporter gene fusion was constructed. hosA expression was significantly reduced in the hosA but not the slyA mutant and was influenced by temperature, salt, and pH. In contrast to SlyA, HosA did not activate the cryptic E. coli K-12 hemolysin ClyA. Mutation of hosA did not influence type III secretion, the regulation of the LEE1 and LEE4 operons, or the ability of E2348/69 to form attaching-and-effacing lesions on intestinal epithelial cells. HosA is, however, involved in the temperature-dependent positive control of motility on swim plates and regulates fliC expression and FliC protein levels. In electrophoretic mobility shift assays, purified HosA protein bound specifically to the fliC promoter, indicating that HosA directly modulates flagellin expression. While direct examination of flagellar structure and the motile behavior of individual hosA cells grown in broth culture at 30°C did not reveal any obvious differences, hosA mutants, unlike the wild type, clumped together, forming nonmotile aggregates which could account for the markedly reduced motility of the hosA mutant on swim plates at 30°C. We conclude that SlyA and HosA are independent transcriptional regulators that respond to different physicochemical cues to facilitate the environmental adaptation of E. coli.
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He, Cynthia Y., Adarsh Singh, and Vyacheslav Yurchenko. "Cell Cycle-Dependent Flagellar Disassembly in a Firebug Trypanosomatid Leptomonas pyrrhocoris." mBio 10, no. 6 (November 26, 2019). http://dx.doi.org/10.1128/mbio.02424-19.
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ABSTRACT Current understanding of flagellum/cilium length regulation focuses on a few model organisms with flagella of uniform length. Leptomonas pyrrhocoris is a monoxenous trypanosomatid parasite of firebugs. When cultivated in vitro, L. pyrrhocoris duplicates every 4.2 ± 0.2 h, representing the shortest doubling time reported for trypanosomatids so far. Each L. pyrrhocoris cell starts its cell cycle with a single flagellum. A new flagellum is assembled de novo, while the old flagellum persists throughout the cell cycle. The flagella in an asynchronous L. pyrrhocoris population exhibited a vast length variation of ∼3 to 24 μm, casting doubt on the presence of a length regulation mechanism based on a single balance point between the assembly and disassembly rate in these cells. Through imaging of live L. pyrrhocoris cells, a rapid, partial disassembly of the existing, old flagellum is observed upon, if not prior to, the initial assembly of a new flagellum. Mathematical modeling demonstrated an inverse correlation between the flagellar growth rate and flagellar length and inferred the presence of distinct, cell cycle-dependent disassembly mechanisms with different rates. On the basis of these observations, we proposed a min-max model that could account for the vast flagellar length range observed for asynchronous L. pyrrhocoris. This model may also apply to other flagellated organisms with flagellar length variation. IMPORTANCE Current understanding of flagellum biogenesis during the cell cycle in trypanosomatids is limited to a few pathogenic species, including Trypanosoma brucei, Trypanosoma cruzi, and Leishmania spp. The most notable characteristics of trypanosomatid flagella studied so far are the extreme stability and lack of ciliary disassembly/absorption during the cell cycle. This is different from cilia in Chlamydomonas and mammalian cells, which undergo complete absorption prior to cell cycle initiation. In this study, we examined flagellum duplication during the cell cycle of Leptomonas pyrrhocoris. With the shortest duplication time documented for all Trypanosomatidae and its amenability to culture on agarose gel with limited mobility, we were able to image these cells through the cell cycle. Rapid, cell cycle-specific flagellum disassembly different from turnover was observed for the first time in trypanosomatids. Given the observed length-dependent growth rate and the presence of different disassembly mechanisms, we proposed a min-max model that can account for the flagellar length variation observed in L. pyrrhocoris.
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Millar, Jess A., and Rahul Raghavan. "Modulation of Bacterial Fitness and Virulence Through Antisense RNAs." Frontiers in Cellular and Infection Microbiology 10 (February 11, 2021). http://dx.doi.org/10.3389/fcimb.2020.596277.
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Regulatory RNAs contribute to gene expression control in bacteria. Antisense RNAs (asRNA) are a class of regulatory RNAs that are transcribed from opposite strands of their target genes. Typically, these untranslated transcripts bind to cognate mRNAs and rapidly regulate gene expression at the post-transcriptional level. In this article, we review asRNAs that modulate bacterial fitness and increase virulence. We chose examples that underscore the variety observed in nature including, plasmid- and chromosome-encoded asRNAs, a riboswitch-regulated asRNA, and asRNAs that require other RNAs or RNA-binding proteins for stability and activity. We explore how asRNAs improve bacterial fitness and virulence by modulating plasmid acquisition and maintenance, regulating transposon mobility, increasing resistance against bacteriophages, controlling flagellar production, and regulating nutrient acquisition. We conclude with a brief discussion on how this knowledge is helping to inform current efforts to develop new therapeutics.
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Fan, Xiaojing, Zhiwen Zhao, Tingyan Sun, Wei Rou, Caiying Gui, Tahira Saleem, Xuxu Zhao, et al. "The LysR-Type Transcriptional Regulator CrgA Negatively Regulates the Flagellar Master Regulator flhDC in Ralstonia solanacearum GMI1000." Journal of Bacteriology 203, no. 1 (October 12, 2020). http://dx.doi.org/10.1128/jb.00419-20.
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ABSTRACT The invasion and colonization of host plants by the destructive pathogen Ralstonia solanacearum rely on its cell motility, which is controlled by multiple factors. Here, we report that the LysR-type transcriptional regulator CrgA (RS_RS16695) represses cell motility in R. solanacearum GMI1000. CrgA possesses common features of a LysR-type transcriptional regulator and contains an N-terminal helix-turn-helix motif as well as a C-terminal LysR substrate-binding domain. Deletion of crgA results in an enhanced swim ring and increased transcription of flhDC. In addition, the ΔcrgA mutant possesses more polar flagella than wild-type GMI1000 and exhibits higher expression of the flagellin gene fliC. Despite these alterations, the ΔcrgA mutant did not have a detectable growth defect in culture. Yeast one-hybrid and electrophoretic mobility shift assays revealed that CrgA interacts directly with the flhDC promoter. Expressing the β-glucuronidase (GUS) reporter under the control of the crgA promoter showed that crgA transcription is dependent on cell density. Soil-soaking inoculation with the crgA mutant caused wilt symptoms on tomato (Solanum lycopersicum L. cv. Hong yangli) plants earlier than inoculation with the wild-type GMI1000 but resulted in lower disease severity. We conclude that the R. solanacearum regulator CrgA represses flhDC expression and consequently affects the expression of fliC to modulate cell motility, thereby conditioning disease development in host plants. IMPORTANCE Ralstonia solanacearum is a widely distributed soilborne plant pathogen that causes bacterial wilt disease on diverse plant species. Motility is a critical virulence attribute of R. solanacearum because it allows this pathogen to efficiently invade and colonize host plants. In R. solanacearum, motility-defective strains are markedly affected in pathogenicity, which is coregulated with multiple virulence factors. In this study, we identified a new LysR-type transcriptional regulator (LTTR), CrgA, that negatively regulates motility. The mutation of the corresponding gene leads to the precocious appearance of wilt symptoms on tomato plants when the pathogen is introduced using soil-soaking inoculation. This study indicates that the regulation of R. solanacearum motility is more complex than previously thought and enhances our understanding of flagellum regulation in R. solanacearum.
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Liu, Xiaoxiang, Yifan Ye, Yin Zhu, Lifang Wang, Leyang Yuan, Junli Zhu, and Aihua Sun. "Involvement of RpoN in Regulating Motility, Biofilm, Resistance, and Spoilage Potential of Pseudomonas fluorescens." Frontiers in Microbiology 12 (May 31, 2021). http://dx.doi.org/10.3389/fmicb.2021.641844.
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Pseudomonas fluorescens is a typical spoiler of proteinaceous foods, and it is characterized by high spoilage activity. The sigma factor RpoN is a well-known regulator controlling nitrogen assimilation and virulence in many pathogens. However, its exact role in regulating the spoilage caused by P. fluorescens is unknown. Here, an in-frame deletion mutation of rpoN was constructed to investigate its global regulatory function through phenotypic and RNA-seq analysis. The results of phenotypic assays showed that the rpoN mutant was deficient in swimming motility, biofilm formation, and resistance to heat and nine antibiotics, while the mutant increased the resistance to H2O2. Moreover, the rpoN mutant markedly reduced extracellular protease and total volatile basic nitrogen (TVB-N) production in sterilized fish juice at 4°C; meanwhile, the juice with the rpoN mutant showed significantly higher sensory scores than that with the wild-type strain. To identify RpoN-controlled genes, RNA-seq-dependent transcriptomics analysis of the wild-type strain and the rpoN mutant was performed. A total of 1224 genes were significantly downregulated, and 474 genes were significantly upregulated by at least two folds at the RNA level in the rpoN mutant compared with the wild-type strain, revealing the involvement of RpoN in several cellular processes, mainly flagellar mobility, adhesion, polysaccharide metabolism, resistance, and amino acid transport and metabolism; this may contribute to the swimming motility, biofilm formation, stress and antibiotic resistance, and spoilage activities of P. fluorescens. Our results provide insights into the regulatory role of RpoN of P. fluorescens in food spoilage, which can be valuable to ensure food quality and safety.
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Kimura, Tomohiro, Takeaki Tezuka, Daisuke Nakane, Takayuki Nishizaka, Shin-Ichi Aizawa, and Yasuo Ohnishi. "Characterization of Zoospore Type IV Pili inActinoplanes missouriensis." Journal of Bacteriology 201, no. 14 (April 29, 2019). http://dx.doi.org/10.1128/jb.00746-18.
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ABSTRACTThe rare actinomyceteActinoplanes missouriensisproduces terminal sporangia containing a few hundred flagellated spores. After release from the sporangia, the spores swim rapidly in aquatic environments as zoospores. The zoospores stop swimming and begin to germinate in niches for vegetative growth. Here, we report the characterization and functional analysis of zoospore type IV pili inA. missouriensis. The pilus gene (pil) cluster, consisting of three apparently σFliA-dependent transcriptional units, is activated during sporangium formation similarly to the flagellar gene cluster, indicating that the zoospore has not only flagella but also pili. With a new method in which zoospores were fixed with glutaraldehyde to prevent pilus retraction, zoospore pili were observed relatively easily using transmission electron microscopy, showing 6 ± 3 pili per zoospore (n = 37 piliated zoospores) and a length of 0.62 ± 0.35 μm (n = 206), via observation offliC-deleted, nonflagellated zoospores. No pili were observed in the zoospores of a prepilin-encodingpilAdeletion (ΔpilA) mutant. In addition, the deletion ofpilT, which encodes an ATPase predicted to be involved in pilus retraction, substantially reduced the frequency of pilus retraction. Several adhesion experiments using wild-type and ΔpilAzoospores indicated that the zoospore pili are required for the sufficient adhesion of zoospores to hydrophobic solid surfaces. Many zoospore-forming rare actinomycetes conserve thepilcluster, which indicates that the zoospore pili yield an evolutionary benefit in the adhesion of zoospores to hydrophobic materials as footholds for germination in their mycelial growth.IMPORTANCEBacterial zoospores are interesting cells in that their physiological state changes dynamically: they are dormant in sporangia, show temporary mobility after awakening, and finally stop swimming to germinate in niches for vegetative growth. However, the cellular biology of a zoospore remains largely unknown. This study describes unprecedented zoospore type IV pili in the rare actinomyceteActinoplanes missouriensis. Similar to the case for the usual bacterial type IV pili, zoospore pili appeared to be retractable. Our findings that the zoospore pili have a functional role in the adhesion of zoospores to hydrophobic solid surfaces and that the zoospores use both pili and flagella properly according to their different purposes provide an important insight into the cellular biology of the zoospore.