scholarly journals The Parachlorella Genome and Transcriptome Endorse Active RWP-RK, Meiosis and Flagellar Genes in Trebouxiophycean Algae

CYTOLOGIA ◽  
2019 ◽  
Vol 84 (4) ◽  
pp. 323-330
Author(s):  
Shuhei Ota ◽  
Kenshiro Oshima ◽  
Tomokazu Yamazaki ◽  
Tsuyoshi Takeshita ◽  
Kateřina Bišová ◽  
...  
Keyword(s):  
Flagellar Genes

scholarly journals Role of the Helicobacter hepaticus Flagellar Sigma Factor FliA in Gene Regulation and Murine Colonization

2008 ◽  
Vol 190 (19) ◽  
pp. 6398-6408 ◽  
Author(s):  
Torsten Sterzenbach ◽  
Lucie Bartonickova ◽  
Wiebke Behrens ◽  
Birgit Brenneke ◽  
Jessika Schulze ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Sigma Factor ◽  
Intestinal Inflammation ◽  
Gall Stone ◽  
Helicobacter Hepaticus ◽  
Intestinal Colonization ◽  
Wild Type ◽  
Chronic Intestinal Inflammation ◽  
Flagellar Genes

ABSTRACT The enterohepatic Helicobacter species Helicobacter hepaticus colonizes the murine intestinal and hepatobiliary tract and is associated with chronic intestinal inflammation, gall stone formation, hepatitis, and hepatocellular carcinoma. Thus far, the role of H. hepaticus motility and flagella in intestinal colonization is unknown. In other, closely related bacteria, late flagellar genes are mainly regulated by the sigma factor FliA (σ28). We investigated the function of the H. hepaticus FliA in gene regulation, flagellar biosynthesis, motility, and murine colonization. Competitive microarray analysis of the wild type versus an isogenic fliA mutant revealed that 11 genes were significantly more highly expressed in wild-type bacteria and 2 genes were significantly more highly expressed in the fliA mutant. Most of these were flagellar genes, but four novel FliA-regulated genes of unknown function were identified. H. hepaticus possesses two identical copies of the gene encoding the FliA-dependent major flagellin subunit FlaA (open reading frames HH1364 and HH1653). We characterized the phenotypes of mutants in which fliA or one or both copies of the flaA gene were knocked out. flaA_1 flaA_2 double mutants and fliA mutants did not synthesize detectable amounts of FlaA and possessed severely truncated flagella. Also, both mutants were nonmotile and unable to colonize mice. Mutants with either flaA gene knocked out produced flagella morphologically similar to those of wild-type bacteria and expressed FlaA and FlaB. flaA_1 mutants which had flagella but displayed reduced motility did not colonize mice, indicating that motility is required for intestinal colonization by H. hepaticus and that the presence of flagella alone is not sufficient.

scholarly journals Basal Body Structures Differentially Affect Transcription of RpoN- and FliA-Dependent Flagellar Genes in Helicobacter pylori

2015 ◽  
Vol 197 (11) ◽  
pp. 1921-1930 ◽  
Author(s):  
Jennifer Tsang ◽  
Timothy R. Hoover
Keyword(s):  
Helicobacter Pylori ◽  
Basal Body ◽  
Protein Interactions ◽  
Transcript Levels ◽  
Content Type ◽  
Genes Encoding ◽  
H Pylori ◽  
Flagellar Biogenesis ◽  
Flagellar Genes

ABSTRACTFlagellar biogenesis inHelicobacter pyloriis regulated by a transcriptional hierarchy governed by three sigma factors, RpoD (σ80), RpoN (σ54), and FliA (σ28), that temporally coordinates gene expression with the assembly of the flagellum. Previous studies showed that loss of flagellar protein export apparatus components inhibits transcription of flagellar genes. The FlgS/FlgR two-component system activates transcription of RpoN-dependent genes though an unknown mechanism. To understand better the extent to which flagellar gene regulation is coupled to flagellar assembly, we disrupted flagellar biogenesis at various points and determined how these mutations affected transcription of RpoN-dependent (flaBandflgE) and FliA-dependent (flaA) genes. The MS ring (encoded byfliF) is one of the earliest flagellar structures assembled. Deletion offliFresulted in the elimination of RpoN-dependent transcripts and an ∼4-fold decrease inflaAtranscript levels. FliH is a cytoplasmic protein that functions with the C ring protein FliN to shuttle substrates to the export apparatus. Deletions offliHand genes encoding C ring components (fliMandfliY) decreased transcript levels offlaBandflgEbut had little or no effect on transcript levels offlaA. Transcript levels offlaBandflgEwere elevated in mutants where genes encoding rod proteins (fliEandflgBC) were deleted, while transcript levels offlaAwas reduced ∼2-fold in both mutants. We propose that FlgS responds to an assembly checkpoint associated with the export apparatus and that FliH and one or more C ring component assist FlgS in engaging this flagellar structure.IMPORTANCEThe mechanisms used by bacteria to couple transcription of flagellar genes with assembly of the flagellum are poorly understood. The results from this study identified components of theH. pyloriflagellar basal body that either positively or negatively affect expression of RpoN-dependent flagellar genes. Some of these basal body proteins may interact directly with regulatory proteins that control transcription of theH. pyloriRpoN regulon, a hypothesis that can be tested by examining protein-protein interactionsin vitro.

scholarly journals Diatom flagellar genes and their expression during sexual reproduction in Leptocylindrus danicus

BMC Genomics ◽  
2017 ◽  
Vol 18 (1) ◽  
Author(s):  
Deepak Nanjappa ◽  
Remo Sanges ◽  
Maria I. Ferrante ◽  
Adriana Zingone
Keyword(s):  
Sexual Reproduction ◽  
Flagellar Genes

scholarly journals Use of pulsed field gel electrophoresis and transposon mutagenesis to estimate the minimal number of genes required for motility in Caulobacter crescentus.

Genetics ◽  
1989 ◽  
Vol 123 (4) ◽  
pp. 649-654 ◽  
Author(s):  
B Ely ◽  
T W Ely
Keyword(s):  
Gel Electrophoresis ◽  
Caulobacter Crescentus ◽  
Pulsed Field Gel Electrophoresis ◽  
Restriction Fragments ◽  
Pulsed Field ◽  
Transposon Insertion ◽  
Number Of Genes ◽  
Physical And Genetic Map ◽  
Insertion Mutations ◽  
Flagellar Genes

Abstract To facilitate the mapping of transposon insertion mutations in Caulobacter crescentus, we have used pulsed field gel electrophoresis to construct a detailed physical and genetic map of the C. crescentus genome. Restriction fragments were generated by DraI, AseI, or SpeI which cleave the C. crescentus 40, 13, and 26 times, respectively, and Tn5 insertions were used to align the restriction fragments generated by each of the enzymes. The utility of the resulting map was demonstrated by determining the chromosomal locations of a collection of flagellar mutations. As a result of this study, we were able to identify ten new flagellar genes at various locations on the chromosome. Thus, at least 48 genes are required for the assembly of a functional flagellum in C. crescentus.

scholarly journals Identification of New Flagellar Genes of Salmonella enterica Serovar Typhimurium

2006 ◽  
Vol 188 (6) ◽  
pp. 2233-2243 ◽  
Author(s):  
Jonathan Frye ◽  
Joyce E. Karlinsey ◽  
Heather R. Felise ◽  
Bruz Marzolf ◽  
Naeem Dowidar ◽  
...  
Keyword(s):  
Salmonella Enterica Serovar Typhimurium ◽  
Transcriptional Start Site ◽  
Null Alleles ◽  
Wild Type ◽  
Gene Encoding ◽  
Isolation And Characterization ◽  
Serovar Typhimurium ◽  
Chemotaxis Proteins ◽  
Flagellar Genes ◽  
Rna Levels

ABSTRACT RNA levels of flagellar genes in eight different genetic backgrounds were compared to that of the wild type by DNA microarray analysis. Cluster analysis identified new, potential flagellar genes, three putative methyl-accepting chemotaxis proteins, STM3138 (McpA), STM3152 (McpB), and STM3216(McpC), and a CheV homolog, STM2314, in Salmonella, that are not found in Escherichia coli. Isolation and characterization of Mud-lac insertions in cheV, mcpB, mcpC, and the previously uncharacterized aer locus of S. enterica serovar Typhimurium revealed them to be controlled by σ28-dependent flagellar class 3 promoters. In addition, the srfABC operon previously isolated as an SsrB-regulated operon clustered with the flagellar class 2 operon and was determined to be under FlhDC control. The previously unclassified fliB gene, encoding flagellin methylase, clustered as a class 2 gene, which was verified using reporter fusions, and the fliB transcriptional start site was identified by primer extension analysis. RNA levels of all flagellar genes were elevated in flgM or fliT null strains. RNA levels of class 3 flagellar genes were elevated in a fliS null strain, while deletion of the fliY, fliZ, or flk gene did not affect flagellar RNA levels relative to those of the wild type. The cafA (RNase G) and yhjH genes clustered with flagellar class 3 transcribed genes. Null alleles in cheV, mcpA, mcpB, mcpC, and srfB did not affect motility, while deletion of yhjH did result in reduced motility compared to that of the wild type.

scholarly journals Flagellum-Mediated Mechanosensing and RflP Control Motility State of Pathogenic Escherichia coli

mBio ◽  
2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Leanid Laganenka ◽  
María Esteban López ◽  
Remy Colin ◽  
Victor Sourjik
Keyword(s):  
Gene Expression ◽  
Escherichia Coli ◽  
Porous Medium ◽  
Biofilm Formation ◽  
Liquid Culture ◽  
Content Type ◽  
E Coli ◽  
Surface Contact ◽  
Conditional Inhibition ◽  
Flagellar Genes

ABSTRACT Bacterial flagellar motility plays an important role in many processes that occur at surfaces or in hydrogels, including adhesion, biofilm formation, and bacterium-host interactions. Consequently, expression of flagellar genes, as well as genes involved in biofilm formation and virulence, can be regulated by the surface contact. In a few bacterial species, flagella themselves are known to serve as mechanosensors, where an increased load on flagella experienced during surface contact or swimming in viscous media controls gene expression. In this study, we show that gene regulation by motility-dependent mechanosensing is common among pathogenic Escherichia coli strains. This regulatory mechanism requires flagellar rotation, and it enables pathogenic E. coli to repress flagellar genes at low loads in liquid culture, while activating motility in porous medium (soft agar) or upon surface contact. It also controls several other cellular functions, including metabolism and signaling. The mechanosensing response in pathogenic E. coli depends on the negative regulator of motility, RflP (YdiV), which inhibits basal expression of flagellar genes in liquid. While no conditional inhibition of flagellar gene expression in liquid and therefore no upregulation in porous medium was observed in the wild-type commensal or laboratory strains of E. coli, mechanosensitive regulation could be recovered by overexpression of RflP in the laboratory strain. We hypothesize that this conditional activation of flagellar genes in pathogenic E. coli reflects adaptation to the dual role played by flagella and motility during infection. IMPORTANCE Flagella and motility are widespread virulence factors among pathogenic bacteria. Motility enhances the initial host colonization, but the flagellum is a major antigen targeted by the host immune system. Here, we demonstrate that pathogenic E. coli strains employ a mechanosensory function of the flagellar motor to activate flagellar expression under high loads, while repressing it in liquid culture. We hypothesize that this mechanism allows pathogenic E. coli to regulate its motility dependent on the stage of infection, activating flagellar expression upon initial contact with the host epithelium, when motility is beneficial, but reducing it within the host to delay the immune response.

scholarly journals Hundreds of Flagellar Basal Bodies Cover the Cell Surface of the Endosymbiotic Bacterium Buchnera aphidicola sp. Strain APS

2006 ◽  
Vol 188 (18) ◽  
pp. 6539-6543 ◽  
Author(s):  
Kazuki Maezawa ◽  
Shuji Shigenobu ◽  
Hisaaki Taniguchi ◽  
Takeo Kubo ◽  
Shin-ichi Aizawa ◽  
...  
Keyword(s):  
Cell Surface ◽  
Basal Bodies ◽  
Endosymbiotic Bacterium ◽  
Symbiotic System ◽  
Buchnera Aphidicola ◽  
Flagellin Gene ◽  
Small Genome ◽  
Late Genes ◽  
Flagellar Proteins ◽  
Flagellar Genes

ABSTRACT Buchnera aphidicola is the endosymbiotic bacterium of the pea aphid. Due to its small genome size, Buchnera lacks many essential genes for autogenous life but obtains nutrients from the host. Although the Buchnera cell is nonmotile, it retains clusters of flagellar genes that lack the late genes necessary for motility, including the flagellin gene. In this study, we show that the flagellar genes are actually transcribed and translated and that the Buchnera cell surface is covered with hundreds of hook-basal-body (HBB) complexes. The abundance of HBB complexes suggests a role other than motility. We discuss the possibility that the HBB complex may serve as a protein transporter not only for the flagellar proteins but also for other proteins to maintain the symbiotic system.

scholarly journals Functional analysis of the flagellar genes in the fliD operon of Salmonella typhimurium

Microbiology ◽  
1995 ◽  
Vol 141 (7) ◽  
pp. 1715-1722 ◽  
Author(s):  
T. Yokoseki ◽  
K. Kutsukake ◽  
K. Ohnishi ◽  
T. lino
Keyword(s):  
Functional Analysis ◽  
Salmonella Typhimurium ◽  
Flagellar Genes
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