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Journal of Bacteriology

Philip M Ireland, Helen L Bullifent, Nicola J Senior, Stephanie J Southern, Zheng Rong Yang, Rachel E Ireland, Michelle Nelson, Helen S Atkins, Richard W Titball, Andrew E Scott
The highly virulent intracellular pathogen Francisella tularensis is a Gram negative bacterium that has a wide host range including humans and is the causative agent of tularemia. To identify new therapeutic drug targets, vaccine candidates and investigate the genetic basis of Francisella virulence in the Fischer 344 rat we have constructed an F. tularensis Schu S4 transposon library. This library consists of over 300,000 unique transposon mutants and represents a transposon insertion for every 6 bp of the genome...
January 14, 2019: Journal of Bacteriology
Amy E Baker, Shanice S Webster, Andreas Diepold, Sherry L Kuchma, Eric Bordeleau, Judith P Armitage, George A O'Toole
Flagellar motility is critical for surface attachment and biofilm formation in many bacteria. A key regulator of flagellar motility in Pseudomonas aeruginosa and other microbes is cyclic diguanylate (c-di-GMP). High levels of this second messenger repress motility and stimulate biofilm formation. C-di-GMP levels regulate motility in P. aeruginosa in part by influencing the localization of its two flagellar stator sets, MotAB and MotCD. Here we show that while c-di-GMP can influence stator localization, stators can in turn impact c-di-GMP levels...
January 14, 2019: Journal of Bacteriology
Lydia J Kreuter, Andrea Weinfurtner, Alexander Ziegler, Julia Weigl, Jan Hoffmann, Nina Morgner, Volker Müller, Harald Huber
In this study, the ATP synthase of Ignicoccus hospitalis was purified, characterized and structurally compared to the respective enzymes of the other Ignicoccus species to shed light on energy conservation in this unique group of Archaea. The crenarchaeal genus Ignicoccus comprises three described species: I. hospitalis and I. islandicus from hot marine sediments near Iceland and I. pacificus from a hydrothermal vent system in the Pacific Ocean. This genus is unique among all Archaea due to the unusual cell envelope consisting of two membranes that enclose a large intermembrane compartment (IMC)...
January 14, 2019: Journal of Bacteriology
Robert L Bertrand
Lag is a temporary period of non-replication seen in bacteria that are introduced to new media. Despite latency being described by Müller in 1895, until only recently have we gained insights into the cellular processes characterizing lag phase. This review covers literature to date on the transcriptomic, proteomic, metabolomic, physiological, biochemical, and evolutionary features of prokaryotic lag. Though lag is commonly described as a preparative phase that allows bacteria to harvest nutrients and adapt to new environments, the implications of recent studies indicate that a refinement of this view is well-deserved...
January 14, 2019: Journal of Bacteriology
Tara Gallagher, Joann Phan, Andrew Oliver, Alexander B Chase, Whitney E England, Stephen Wandro, Clark Hendrickson, Stefan F Riedel, Katrine Whiteson
The airway fluids of cystic fibrosis (CF) patients contain local pH gradients and are more acidic than that of healthy indviduals. pH is a critical factor that is often overlooked in studies seeking to recapitulate the infection microenvironment. We sought to determine the impact of pH on the physiology of a ubiqituous yet understudied microbe, Stenotrophomonas maltophilia. Phylogenomics was first used to reconstruct evolutionary relationships between 74 strains of S. maltophilia (59 from CF patients). Neither the core genome (2,158 genes) nor the accessory genome (11,978 genes) distinguish the CF and non-CF isolates, however, strains from similar isolation sources grouped into the same sub-clades...
January 14, 2019: Journal of Bacteriology
Richa Misra, Dilip Menon, Gunjan Arora, Richa Virmani, Mohita Gaur, Saba Naz, Neetika Jaisinghani, Asani Bhaduri, Ankur Bothra, Abhijit Maji, Anshika Singhal, Preeti Karwal, Christian Hentschker, Dörte Becher, Vivek Rao, Vinay K Nandicoori, Sheetal Gandotra, Yogendra Singh
Bacterial alternative sigma factors are mostly regulated by a partner-switching mechanism. Regulation of the virulence associated alternative sigma factor, SigF, of Mycobacterium tuberculosis , has been an area of intrigue with more predicted regulators compared to other sigma factors in this organism. Rv1364c is one such predicted regulator, the mechanism of which is confounded by the presence of both anti-sigma and anti-sigma-antagonist functions in a single polypeptide. Using protein binding and phosphorylation assays, we demonstrate that the anti-sigma factor domain of Rv1364c mediates autophosphorylation of its antagonist domain and binds efficiently to SigF...
January 14, 2019: Journal of Bacteriology
Yuya Suzuki, Yusuke V Morimoto, Kodai Oono, Fumio Hayashi, Kenji Oosawa, Seishi Kudo, Shuichi Nakamura
The bacterial flagellar motor is composed of a rotor and a dozen stators and converts the ion flux through the stator into torque. Each stator unit alternates in its attachment to and detachment from the rotor even during rotation. In some species, stator assembly depends on the input energy, but it remains unclear how an electrochemical potential across the membrane (e.g., proton motive force; PMF) or ion flux is involved in stator assembly dynamics. Here we focused on pH dependence of a slow motile MotA(M206I) mutant of Salmonella The MotA(M206I) motor produces torque comparable to the wild-type motor near stall, but its rotation rate is considerably decreased as the external load is reduced...
January 14, 2019: Journal of Bacteriology
Michael Wells, Jennifer McGarry, Maissa M Gaye, Partha Basu, Ronald S Oremland, John F Stolz
The putative respiratory selenite [Se(IV)] reductase (Srr) from MLS10 has been identified through a polyphasic approach involving genomics, proteomics, and enzymology. Non-denaturing gel assays were used to identify Srr in cell fractions and the active band was shown to contain a single protein of 80 kDa. The protein was identified through LC-MS-MS as a homolog of the catalytic subunit of polysulfide reductase (PsrA). It was found to be part of an operon that contains six genes that we designated srrE, srrA , s rrB, srrC, srrD, srrF SrrA is the catalytic subunit (80 kDa), with a TAT leader sequence indicative of a periplasmic protein and one putative 4Fe-4S binding site...
January 14, 2019: Journal of Bacteriology
Chong M Lee, Guanshi Wang, Alexandros Pertsinidis, Kenneth J Marians
The role of DNA topoisomerase III (Topo III) in bacterial cells has proven elusive. Whereas eukaryotic Top IIIα homologs are clearly involved with homologs of the bacterial DNA helicase RecQ in unraveling double Holliday junctions, preventing crossover exchange of genetic information at unscheduled recombination intermediates, and Top IIIβ homologs have been shown to be involved in regulation of various mRNAs involved in neuronal function, little evidence for similar reactions exists in bacteria. Instead, most data points to Topo III playing a supplemental role to topoisomerase IV in unlinking daughter chromosomes during DNA replication...
January 7, 2019: Journal of Bacteriology
Maike M Glaser, Penelope I Higgs
His-Asp phosphorelay (a.k.a. two-component signal transduction) proteins are the predominant mechanism used in most bacteria to control behavior in response to changing environmental conditions. In addition to systems consisting of a simple two-component system utilizing an isolated histidine kinase/response regulator pair, some bacteria are enriched in histidine kinases that serve as signal integration proteins; these kinases are usually characterized by non-canonical domain architecture and the responses that they regulate may be difficult to identify...
January 7, 2019: Journal of Bacteriology
Maxwell R Fishman, Melanie J Filiatrault
CvsSR is a Ca2+ -induced two-component system (TCS) in the plant pathogen Pseudomonas syringae pv. tomato DC3000 ( Pto ). Here we discovered CvsSR is induced by Fe3+ , Zn2+ , and Cd2+ However, only supplementation of Ca2+ to medium resulted in rugose, opaque colonies in Δ cvsS and Δ cvsR strains. This phenotype corresponded to formation of calcium phosphate precipitation on the surface of Δ cvsS and Δ cvsR colonies. CvsSR regulated swarming motility in Pto in a Ca2+ -dependent manner, but swarming behavior was not influenced by Fe3+ , Zn2+ , or Cd2+ We hypothesized that reduced swarming displayed by Δ cvsS and Δ cvsR was due to precipitation of calcium phosphate on the surface of Δ cvsS and Δ cvsR grown on agar medium supplemented with Ca2+ By reducing the initial pH or adding glucose to the medium, calcium precipitation was inhibited and swarming was restored to Δ cvsS and Δ cvsR , suggesting calcium precipitation influences swarming ability...
January 7, 2019: Journal of Bacteriology
Wooi Keong Teh, Shaynoor Dramsi, Tim Tolker-Nielsen, Liang Yang, Michael Givskov
Cyclic-di-AMP is a recently identified second messenger exploited by a number of Gram-positive bacteria to regulate important biological processes. Here, we studied the phenotypic alterations induced by increased intracellular c-di-AMP levels in Streptococcus gallolyticus , an opportunistic pathogen responsible for septicemia and endocarditis in the elderly. We report that a S. gallolyticus c-di-AMP phosphodiesterase gdpP knock-out mutant, which displays a 1.5-fold higher intracellular c-di-AMP levels as compared to the parental strain UCN34, is more sensitive to osmotic stress and is morphologically smaller than the parental strain...
January 7, 2019: Journal of Bacteriology
Jing-Wen Li, Jing Li, Juanjuan Wang, Chunhao Li, Jing-Ren Zhang
Streptococcus pneumoniae (pneumococcus), a major human pathogen, is well known for its adaptation to various host environments. Multiple DNA inversions in the three DNA methyltransferase hsdS genes ( hsdSA , hsdSB and hsdSC ) of colony opacity determinant ( cod ) locus generate extensive epigenetic and phenotypic diversity. However, it is unclear whether all three hsdS genes are functional and how the inversions mechanistically occur. In this work, our transcriptional analysis revealed active expression for hsdSA but not hsdSB and hsdSC , indicating that hsdSB and hsdSC don't produce functional proteins and instead act as sources for altering the sequence of hsdSA by DNA inversions...
January 7, 2019: Journal of Bacteriology
Anuja C Joshi, Prabhjot Kaur, Radhika K Nair, Deepti S Lele, Vinay Kumar Nandicoori, Balasubramanian Gopal
Extracytoplasmic Function σ factors that are stress inducible are often sequestered in an inactive complex with a membrane-associated anti-σ factor. M. tuberculosis membrane associated anti-σ factors have a small stable RNA gene A-like degron for targeted proteolysis. Interaction between the unfoldase, ClpX, and the substrate with an accessible degron initiates energy-dependent proteolysis. Four anti-σ factors with a mutation in the degron provided a set of natural substrates to evaluate the influence of the degron on degradation strength in ClpX substrate processivity...
January 7, 2019: Journal of Bacteriology
Qingqing Gao, Le Xia, Xiaobo Wang, Zhengqin Ye, Jinbiao Liu, Song Gao
Avian pathogenic Escherichia coli (APEC), the common pathogen of avian colibacillosis, encounter reactive oxygen species (ROS) during the infection process. Superoxide dismutases (SODs), acting as antioxidant factors, can protect against ROS-mediated host defenses. Our previous reports showed that the sodA gene (encoding a Mn-cofactor-containing SOD [MnSOD]) is highly expressed during the septicemic infection process of APEC. sodA has been proved to be a virulence factor of certain pathogens, but its role in the pathogenicity of APEC has not been fully identified...
January 2, 2019: Journal of Bacteriology
Yan Chen, Bidisha Barat, W Keith Ray, Richard F Helm, Stephen B Melville, David L Popham
Bacterial endospores produced by Bacillus and Clostridium species can remain dormant and highly resistant to environmental insults for long periods but can also rapidly germinate in response to a nutrient rich environment. Multiple proteins involved in sensing and responding to nutrient germinants, initiating solute and water transport, and accomplishing spore wall degradation are associated with the membrane surrounding the spore core. In order to more fully catalog proteins that may be involved in spore germination as well as to identify protein changes taking place during germination, unbiased proteomic analyses of membrane preparations isolated from dormant and germinated spores of Bacillus anthracis and Bacillus subtilis were undertaken...
January 2, 2019: Journal of Bacteriology
Tra-My Hoang, C Zhou, J K Lindgren, M R Galac, B Corey, J E Endres, M E Olson, P D Fey
S. epidermidis is a primary cause of biofilm-mediated infections in humans due to adherence to foreign bodies. A major staphylococcal biofilm accumulation molecule is polysaccharide intracellular adhesin (PIA), which is synthesized by enzymes encoded by the icaADBC operon. Expression of PIA is highly variable amongst clinical isolates suggesting that PIA expression levels are selected in certain niches of the host. However, mechanisms that govern enhanced icaADBC transcription and PIA synthesis in these isolates is not known...
January 2, 2019: Journal of Bacteriology
Caleb Pérez-González, Clelia Domenzain, Sebastian Poggio, Diego González-Halphen, Georges Dreyfus, Laura Camarena
The flagellar lipoprotein FlgP has been identified in several species of bacteria and, its absence provokes different phenotypes. In this work we show that in the α proteobacterium Rhodobacter sphaeroides , a Δ flgP mutant is unable to assemble the hook and the filament. In contrast, the MS ring and the flagellar rod appear to be assembled. In the absence of FlgP a severe defect in the transition from rod to hook polymerization occurs. In agreement with this idea, we noticed a reduction in the amount of intracellular flagellin and the chemotactic protein CheY4, both encoded by genes dependent on σ28 This suggests that in the absence of flgP the switch to export the anti-sigma factor, FlgM, does not occur...
December 17, 2018: Journal of Bacteriology
Tianjian Hu, Lingzhi Zhang, Wei Wang, Dahai Yang, Jingfan Xiao, Yuanxing Zhang, Xiaohong Liu, Qin Liu
Edwardsiella piscicida is an important pathogen that infects a wide range of hosts from fish to human. Recent studies demonstrated that E. piscicida can invade and survive within multiple non-phagocytic cells, but the internalization mechanism remains poorly understood. Here, we employed HeLa cells as a non-phagocytic cell model to investigate the endocytic strategy used by the pathogenic E. piscicida isolate EIB202. Using a combination of optical and electron microscopy, we observed obvious membrane ruffles and F-actin rearrangements in HeLa cells after EIB202 infection...
December 10, 2018: Journal of Bacteriology
Courtney E Chandler, Alexander M Horspool, Preston J Hill, Daniel J Wozniak, Jeffrey W Schertzer, David A Rasko, Robert K Ernst
Pseudomonas aeruginosa is an opportunistic pathogen, found ubiquitously in the environment and commonly associated with airway infection in patients with cystic fibrosis. P. aeruginosa strain PAO1 is one of the most commonly used laboratory-adapted research strains and is a standard laboratory-adapted strain in multiple laboratories and strain banks worldwide. Due to potential isolate-to-isolate variability, we investigated the genomic and phenotypic diversity among ten PAO1 strains (henceforth called sublines) obtained from multiple research laboratories and commercial sources...
December 10, 2018: Journal of Bacteriology
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