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https://www.readbyqxmd.com/read/28100305/environment-directed-activation-the-escherichia-coli-flhdc-operon-by-transposons
#1
Zhongge Zhang, Chika Kukita, Mir Zafri Humayun, Milton H Saier
The flagellar system in E. coli K12 is expressed under the control of the flhDC-encoded master regulator, FlhDC. Transposition of insertion sequence (IS) elements to the upstream flhDC promoter region up-regulates transcription of this operon, resulting in more rapid motility. Wang and Wood (2011) provided evidence that insertion of IS5 into upstream activating sites occurs at higher rates in semisolid agar media in which swarming behavior is allowed as compared with liquid or solid media where swarming cannot occur...
January 17, 2017: Microbiology
https://www.readbyqxmd.com/read/28091933/flagellar-regulation-and-virulence-in-the-entomopathogenic-bacteria-xenorhabdus-nematophila-and-photorhabdus-luminescens
#2
Alain Givaudan, Anne Lanois
There is a complex interplay between the regulation of flagellar motility and the expression of virulence factors in many bacterial pathogens. Here, we review the literature on the direct and indirect roles of flagellar motility in mediating the tripartite interaction between entomopathogenic bacteria (Photorhabdus and Xenorhabdus), their nematode hosts, and their insect targets. First, we describe the swimming and swarming motility of insect pathogenic bacteria and its impact on insect colonization. Then, we describe the coupling between the expression of flagellar and virulence genes and the dynamic of expression of the flagellar regulon during invertebrate infection...
December 28, 2016: Current Topics in Microbiology and Immunology
https://www.readbyqxmd.com/read/28065820/bioavailability-enhanced-resveramax%C3%A2-modulates-quorum-sensing-and-inhibits-biofilm-formation-in-pseudomonas-aeruginosa-pao1
#3
H S Vasavi, H V Sudeep, H B Lingaraju, K Shyam Prasad
Quorum sensing (QS), a cell-to-cell communication mechanism present in many bacterial species plays a key role in regulating the virulence factor and biofilm formation in many pathogens, which causes severe public health risk. Therefore, interfering with QS mechanism offers an attractive strategy to combat bacterial infections. In the present study, anti-QS activity of a novel resveratrol formulation, Resveramax™, was detected using Chromobacterium violaceum biosensor bioassay and the effect of Resveramax on QS-regulated phenotypes in Pseudomonas aeruginosa PAO1 was assessed by standard protocols...
January 5, 2017: Microbial Pathogenesis
https://www.readbyqxmd.com/read/28056789/evolutionary-diversification-of-pseudomonas-aeruginosa-in-an-artificial-sputum-model
#4
Emily V Davies, Chloe E James, Michael A Brockhurst, Craig Winstanley
BACKGROUND: During chronic lung infections of cystic fibrosis patients Pseudomonas aeruginosa populations undergo extensive evolutionary diversification. However, the selective drivers of this evolutionary process are poorly understood. To test the effects of temperate phages on diversification in P. aeruginosa biofilms we experimentally evolved populations of P. aeruginosa for approximately 240 generations in artificial sputum medium with or without a community of three temperate phages...
January 5, 2017: BMC Microbiology
https://www.readbyqxmd.com/read/28046014/pseudomonas-aeruginosa-sera-gene-is-required-for-bacterial-translocation-through-caco-2-cell-monolayers
#5
Masashi Yasuda, Syouya Nagata, Satoshi Yamane, Chinami Kunikata, Yutaka Kida, Koichi Kuwano, Chigusa Suezawa, Jun Okuda
To specify critical factors responsible for Pseudomonas aeruginosa penetration through the Caco-2 cell epithelial barrier, we analyzed transposon insertion mutants that demonstrated a dramatic reduction in penetration activity relative to P. aeruginosa PAO1 strain. From these strains, mutations could be grouped into five classes, specifically flagellin-associated genes, pili-associated genes, heat-shock protein genes, genes related to the glycolytic pathway, and biosynthesis-related genes. Of these mutants, we here focused on the serA mutant, as the association between this gene and penetration activity is yet unknown...
2017: PloS One
https://www.readbyqxmd.com/read/28036241/suppressor-analysis-of-eepr-mutant-defects-reveals-coordinate-regulation-of-secondary-metabolites-and-serralysin-biosynthesis-by-eepr-and-hexs
#6
Robert M Q Shanks, Nicholas A Stella, Roni M Lahr, Marissa A Aston, Kimberly M Brothers, Jake Callaghan, Cihad Sigindere, Xinyu Liu
The EepR transcription factor positively regulates secondary metabolites and tissue damaging metalloproteases. To gain insight into mechanisms by which EepR regulates pigment and co-regulated factors, genetic suppressor analysis was performed. Suppressor mutations that restored pigment to the non-pigmented ∆eepR mutant mapped to the hexS open reading frame. Mutation of hexS also restored hemolysis, swarming motility, and protease production to the eepR mutant. HexS is a known direct and negative regulator of secondary metabolites in S...
December 30, 2016: Microbiology
https://www.readbyqxmd.com/read/28008851/functional-dichotomy-and-distinct-nanoscale-assemblies-of-a-cell-cycle-controlled-bipolar-zinc-finger-regulator
#7
Johann Mignolet, Seamus Holden, Matthieu Bergé, Gaël Panis, Ezgi Eroglu, Laurence Théraulaz, Suliana Manley, Patrick H Viollier
Protein polarization underlies differentiation in metazoans and in bacteria. How symmetric polarization can instate functional asymmetry remains elusive. Here, we show by super-resolution photo-activated localization microscopy and edgetic mutations that the bitopic zinc-finger protein ZitP implements specialized developmental functions - pilus biogenesis and multifactorial swarming motility - while shaping distinct nanoscale (bi)polar architectures in the asymmetric model bacterium Caulobacter crescentus. Polar assemblage and accumulation of ZitP and its effector protein CpaM are orchestrated in time and space by conserved components of the cell cycle circuitry that coordinate polar morphogenesis with cell cycle progression, and also act on the master cell cycle regulator CtrA...
December 23, 2016: ELife
https://www.readbyqxmd.com/read/28004809/characterization-of-the-relationship-between-polar-and-lateral-flagellar-structural-genes-in-the-deep-sea-bacterium-shewanella-piezotolerans-wp3
#8
Huahua Jian, Han Wang, Xianping Zeng, Lei Xiong, Fengping Wang, Xiang Xiao
Bacteria with a dual flagellar system, which consists of a polar flagellum (PF) and several lateral flagella (LF), have been identified in diverse environments. Nevertheless, whether and how these two flagellar systems interact with each other is largely unknown. In the present study, the relationship between the structural genes for the PF and LF of the deep-sea bacterium Shewanella piezotolerans WP3 was investigated by genetic, phenotypic and phylogenetic analyses. The mutation of PF genes induced the expression of LF genes and the production of LF in liquid medium, while the defective LF genes led to a decrease in PF gene transcription...
December 22, 2016: Scientific Reports
https://www.readbyqxmd.com/read/27990141/the-ecological-coherence-of-temperature-and-salinity-tolerance-interaction-and-pigmentation-in-a-non-marine-vibrio-isolated-from-salar-de-atacama
#9
Karem Gallardo, Jonathan E Candia, Francisco Remonsellez, Lorena V Escudero, Cecilia S Demergasso
The occurrence of microorganisms from the Vibrio genus in saline lakes from northern Chile had been evidenced using Numerical Taxonomy decades before and, more recently, by phylogenetic analyses of environmental samples and isolates. Most of the knowledge about this genus came from marine isolates and showed temperature and salinity to be integral agents in shaping the niche of the Vibrio populations. The stress tolerance phenotypes of Vibrio sp. Teb5a1 isolated from Salar de Atacama was investigated. It was able to grow without NaCl and tolerated up to 100 g/L of the salt...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27983482/lack-of-formylated-methionyl-trna-has-pleiotropic-effects-on-bacillus-subtilis
#10
Yanfei Cai, Pete Chandrangsu, Ahmed Gaballa, John D Helmann
Bacteria initiate translation using a modified amino acid, N-formylmethionine (fMet), adapted specifically for this function. Most proteins are processed co-translationally by peptide deformylase (PDF) to remove this modification. Although PDF activity is essential in wild-type cells, and is the target of the antibiotic actinonin, bypass mutations in the fmt gene that eliminate the formylation of Met-tRNAMet render PDF dispensable. The extent to which the emergence of fmt bypass mutations might compromise the therapeutic utility of actinonin is determined, in part, by the effects of these bypass mutations on fitness...
December 15, 2016: Microbiology
https://www.readbyqxmd.com/read/27965643/the-minor-flagellin-of-campylobacter-jejuni-flab-confers-defensive-properties-against-bacteriophage-infection
#11
Lukas Lis, Ian F Connerton
A screen of bacteriophages infecting a panel of Campylobacter jejuni PT14 gene knock-out mutants identified a role for the minor flagellin encoded by the flaB gene, in the defense of the host against CP8unalikevirus bacteriophage CP_F1 infection. Inactivation of the flaB gene resulted in an increase in the susceptibility of PT14 cultures to infection by CP_F1 and an increase in bacteriophage yields. Infection of wild type PT14 with CP_F1 produces turbid plaques in bacterial lawns, from which 78% of the resistant isolates recovered exhibit either attenuation or complete loss of motility...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27965638/functional-characterization-of-triclosan-resistant-enoyl-acyl-carrier-protein-reductase-fabv-in-pseudomonas-aeruginosa
#12
Yong-Heng Huang, Jin-Shui Lin, Jin-Cheng Ma, Hai-Hong Wang
Pseudomonas aeruginosa is extremely resistant to triclosan. Previous studies have shown that P. aeruginosa encodes a triclosan-resistant enoyl-acyl-carrier protein reductase (ENR), FabV, and that deletion of fabV causes P. aeruginosa to be extremely sensitive to triclosan. In this report, we complemented a P. aeruginosa fabV deletion strain with several triclosan-resistant ENR encoding genes, including Vibrio cholerae fabV, Bacillus subtilis fabL and Enterococcus faecalis fabK. All complemented strains restored triclosan resistance to the level of the wild-type strain, which confirmed that triclosan-resistant ENR allows P...
2016: Frontiers in Microbiology
https://www.readbyqxmd.com/read/27902425/virulence-adaptations-of-pseudomonas-aeruginosa-isolated-from-patients-with-non-cystic-fibrosis-bronchiectasis
#13
Taylor Evart Woo, Jessica Duong, Nicole M Jervis, Harvey R Rabin, Michael D Parkins, Douglas Gordon Storey
Pseudomonas aeruginosa is a major pathogen in chronic lung diseases such as cystic fibrosis (CF) and non-cystic fibrosis bronchiectasis (nCFB). Much of our understanding regarding infections in nCFB patients is extrapolated from findings in CF with little direct investigation on the adaptation of P. aeruginosa in nCFB patients. As such, we investigated whether the adaptation of P. aeruginosa was indeed similar between nCFB and CF. From our prospectively collected biobank we identified 40 nCFB patients who had repeated P...
November 8, 2016: Microbiology
https://www.readbyqxmd.com/read/27879336/beyond-antimicrobial-resistance-evidence-for-a-distinct-role-of-the-acrd-efflux-pump-in-salmonella-biology
#14
Michelle M C Buckner, Jessica M A Blair, Roberto M La Ragione, Jane Newcombe, Daniel J Dwyer, Alasdair Ivens, Laura J V Piddock
: For over 20 years, bacterial multidrug resistance (MDR) efflux pumps have been studied because of their impact on resistance to antimicrobials. However, critical questions remain, including why produce efflux pumps under non-antimicrobial treatment conditions, and why have multiple pumps if their only purpose is antimicrobial efflux? Salmonella spp. possess five efflux pump families, including the resistance-nodulation-division (RND) efflux pumps. Notably, the RND efflux pump AcrD has a unique substrate profile, distinct from other Salmonella efflux pumps...
November 22, 2016: MBio
https://www.readbyqxmd.com/read/27874229/exopolysaccharides-promote-myxococcus-xanthus-social-motility-by-inhibiting-cellular-reversals
#15
Tianyi Zhou, Beiyan Nan
The biofilm-forming bacterium Myxococcus xanthus moves on surfaces as structured swarms utilizing type IV pili-dependent social (S) motility. In contrast to isolated cells that reverse their moving direction frequently, individual cells within swarms rarely reverse. The regulatory mechanisms that inhibit cellular reversal and promote the formation of swarms are not well understood. Here we show that exopolysaccharides (EPS), the major extracellular components of M. xanthus swarms, inhibit cellular reversal in a concentration-dependent manner...
November 22, 2016: Molecular Microbiology
https://www.readbyqxmd.com/read/27873565/patterns-of-virulence-factor-expression-and-antimicrobial-resistance-in-achromobacter-xylosoxidans-and-achromobacter-ruhlandii-isolates-from-patients-with-cystic-fibrosis
#16
R H V Pereira, R S Leão, A P Carvalho-Assef, R M Albano, E R A Rodrigues, M C Firmida, T W Folescu, M C Plotkowski, V G Bernardo, E A Marques
Achromobacter spp. are opportunistic pathogens increasingly recovered from adult patients with cystic fibrosis (CF). We report the characterization of 122 Achromobacter spp. isolates recovered from 39 CF patients by multilocus sequence typing, virulence traits, and susceptibility to antimicrobials. Two species, A. xylosoxidans (77%) and A. ruhlandii (23%) were identified. All isolates showed a similar biofilm formation ability, and a positive swimming phenotype. By contrast, 4·3% and 44·4% of A. xylosoxidans and A...
November 22, 2016: Epidemiology and Infection
https://www.readbyqxmd.com/read/27868330/structural-and-functional-analysis-of-cyclophilin-ppib-mutants-supports-an-in%C3%A2-vivo-function-not-limited-to-prolyl-isomerization-activity
#17
Aggeliki Skagia, Eleni Vezyri, Markezina Sigala, Areti Kokkinou, Michael Karpusas, Anastasia Venieraki, Panagiotis Katinakis, Maria Dimou
Escherichia coli cyclophilin PpiB is a peptidyl-prolyl cis/trans isomerase (PPIase, EC: 5.2.1.8), involved in the negative modulation of various bacterial processes, such as swimming and swarming motility and biofilm formation ability. In this study, we show that PpiB possesses also a chaperone function as it can prevent the thermal denaturation of citrate synthase even with essentially eliminated PPIase activity. We demonstrate, using active site mutations, that the PPIase activity of PpiB is required in all processes, except for the negative effect on swimming, indicating a possible isomerase-independent function...
November 21, 2016: Genes to Cells: Devoted to Molecular & Cellular Mechanisms
https://www.readbyqxmd.com/read/27862537/pervasive-yet-idiosyncratic-epistatic-pleiotropy-during-adaptation-in-a-behaviourally-complex-microbe
#18
P C Zee, J Liu, G J Velicer
Understanding how multiple mutations interact to jointly impact multiple ecologically important traits is critical for creating a robust picture of organismal fitness and the process of adaptation. However, this is complicated by both environmental heterogeneity and the complexity of genotype-to-phenotype relationships generated by pleiotropy and epistasis. Moreover, little is known about how pleiotropic and epistatic relationships themselves change over evolutionary time. The soil bacterium Myxococcus xanthus employs several distinct social traits across a range of environments...
October 19, 2016: Journal of Evolutionary Biology
https://www.readbyqxmd.com/read/27860087/the-effect-of-burdock-leaf-fraction-on-adhesion-biofilm-formation-quorum-sensing-and-virulence-factors-of-pseudomonas-aeruginosa
#19
Z Lou, H Wang, Y Tang, X Chen
AIMS: This study aimed to evaluate the effect of a fraction of burdock (Arctium lappa L.) leaf on the initial adhesion, biofilm formation, quorum sensing and virulence factors of Pseudomonas aeruginosa. METHODS AND RESULTS: Antibiofilm activity of the burdock leaf fraction was studied by the method of crystal violet staining. When the concentration of the burdock leaf fraction was 2·0 mg ml(-1) , the inhibition rates on biofilm formation of P. aeruginosa were 100%...
November 12, 2016: Journal of Applied Microbiology
https://www.readbyqxmd.com/read/27834875/resveratrol-and-coumarin-novel-agricultural-antibacterial-agent-against-ralstonia-solanacearum-in-vitro-and-in-vivo
#20
Juanni Chen, Yanmei Yu, Shili Li, Wei Ding
Bacterial wilt is a destructive disease caused by the phytopathogen Ralstonia solanacearum (R. solanacearum), which is widely found in various tobacco-growing areas all over the world. Botanical bactericidal substances have gradually emerged as a hot topic in modern pesticide research. In this study, the antibacterial activities of two phytochemicals (resveratrol and coumarin) against R. solanacearum and their in vivo and in vitro efficacy for controlling tobacco bacterial wilt were evaluated. We rule out significant biological effects of both phytochemicals using transmission electron microscope (TEM) and fluorescence microscope, which suppressed the growth of R...
November 9, 2016: Molecules: a Journal of Synthetic Chemistry and Natural Product Chemistry
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