Molecular Microbiology

Cover image for Vol. 102 Issue 5

Early View (Online Version of Record published before inclusion in an issue)

Edited By: John D. Helmann

Impact Factor: 3.761

ISI Journal Citation Reports © Ranking: 2015: 32/123 (Microbiology); 86/289 (Biochemistry & Molecular Biology)

Online ISSN: 1365-2958

Associated Title(s): Cellular Microbiology


  1. 1 - 47
  1. Research Articles

    1. The essential cell division protein FtsN contains a critical disulfide bond in a non-essential domain

      Brian M. Meehan, Cristina Landeta, Dana Boyd and Jon Beckwith

      Version of Record online: 2 DEC 2016 | DOI: 10.1111/mmi.13565

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      Mutations in the essential cell division protein FtsN that render it incapable of forming a disulfide bond lead to filamentous growth of E. coli. Formation of this disulfide bond can be catalyzed by the Dsb enzymatic system or it can be introduced spontaneously through growth in an aerobic environment.

    2. A PTS EII mutant library in Group A Streptococcus identifies a promiscuous man-family PTS transporter influencing SLS-mediated hemolysis

      Ganesh S. Sundar, Emrul Islam, Kanika Gera, Yoann Le Breton and Kevin S. McIver

      Version of Record online: 29 NOV 2016 | DOI: 10.1111/mmi.13573

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      Several sugar transporters (Enzyme IICs, EIIC) contribute to the timely expression of the toxin Streptolysin S (SLS), and are redundant for the transport of sugars. The Mannose-specific EII plays an important role in GAS for both PTS carbohydrate metabolism and Streptolysin S expression, potentially allowing for GAS to extract nutrients from the host in order to survive. Black dashed arrows represent the influence of EIIs and other components of carbon metabolism on SLS production.

    3. Combinatorial control of adhesion of Brucella abortus 2308 to host cells by transcriptional rewiring of the trimeric autotransporter btaE gene

      Rodrigo Sieira, Magalí G. Bialer, Mara S. Roset, Verónica Ruiz-Ranwez, Tomás Langer, Gastón M. Arocena, Estefanía Mancini and Angeles Zorreguieta

      Version of Record online: 29 NOV 2016 | DOI: 10.1111/mmi.13576

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      Regulatory network plasticity is a key attribute underlying changes in bacterial gene expression and a source of phenotypic diversity to interact with the environment. Here, we identified a functional HutC-binding site upstream the Brucella adhesin btaE, which was generated de novo by a single point mutation in the Brucella abortus 2308 virulent strain. This transcriptional rewiring event integrated btaE promoter activity and bacterial adhesion into an ancient regulatory network controlling both metabolic and virulence genes, probably as a result of nucleotide variability associated to intrinsic btaE promoter structural features.

    4. Robust Min-system oscillation in the presence of internal photosynthetic membranes in cyanobacteria

      Joshua S. MacCready, Jory Schossau, Katherine W. Osteryoung and Daniel C. Ducat

      Version of Record online: 28 NOV 2016 | DOI: 10.1111/mmi.13571

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      Unlike canonical prokaryotic models for cell division, cyanobacteria possess extensive thylakoid membranes that could disrupt self-organizing dynamics of the Min system, thereby preventing proper division site placement. We find MinCD regulate FtsZ positioning via dynamic MinE-driven oscillations that require thylakoid membrane perforations. Cdv3 also localises a static MinC pool at the midzone to promote division. Therefore, cyanobacterial fission uses a Min system that combines two distinct classic models and can circumnavigate complex membrane topology.

    5. You have full text access to this OnlineOpen article
      Staphylococcus aureus requires at least one FtsK/SpoIIIE protein for correct chromosome segregation

      Helena Veiga and Mariana G. Pinho

      Version of Record online: 25 NOV 2016 | DOI: 10.1111/mmi.13572

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      The two Staphylococcus aureus DNA translocases, SpoIIIE and FtsK, act through independent, but redundant, pathways to ensure proper management of the chromosomes. SpoIIIE forms foci at the septum of ∼ 50% of cells at late stages of septum synthesis. FtsK is a multifunctional septal protein, whose C-terminal domain is not required for correct chromosome management in the presence of SpoIIIE. Absence of both DNA translocases causes severe nucleoid segregation and morphological defects.

    6. Essential role of Bordetella NadC in a quinolinate salvage pathway for NAD biosynthesis

      Timothy J. Brickman, Ryan J. Suhadolc, Pamela J. McKelvey and Sandra K. Armstrong

      Version of Record online: 25 NOV 2016 | DOI: 10.1111/mmi.13566

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      NAD is a vital coenzyme or co-substrate for all living cells. Classical Bordetella species are auxotrophic for pyridines required for NAD biosynthesis. Our report confirms that they lack de novo pathway genes nadA and nadB; however, they possess an orphan de novo pathway gene, nadC, encoding quinolinate phosphoribosyltransferase. nadC is required for use of salvaged quinolinate as an NAD precursor, and its expression is controlled by nicotinic acid and by a NadQ family transcriptional regulator.

  2. MicroCommentary

    1. You have free access to this content
      Discovery of the type VII ESX-1 secretion needle?

      Louis S. Ates and Roland Brosch

      Version of Record online: 25 NOV 2016 | DOI: 10.1111/mmi.13579

  3. Research Articles

    1. You have full text access to this OnlineOpen article
      EspC forms a filamentous structure in the cell envelope of Mycobacterium tuberculosis and impacts ESX-1 secretion

      Ye Lou, Jan Rybniker, Claudia Sala and Stewart T. Cole

      Version of Record online: 25 NOV 2016 | DOI: 10.1111/mmi.13575

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      EspC is a small, helical hairpin protein restricted to pathogenic mycobacteria, like Mycobacterium tuberculosis, where it impacts the function of the ESX-1 secretion system and controls pathogenesis. Purified EspC polymerizes into filaments with a diameter of 10–15 nm and similar structures may be found in the capsule layer. It is conceivable that the EspC filaments are either a component of the secretion apparatus itself or that they modulate its function in an essential manner.

    2. The pleiotropic transcriptional regulator NlpR contributes to the modulation of nitrogen metabolism, lipogenesis and triacylglycerol accumulation in oleaginous rhodococci

      Martín A. Hernández, Julia Lara, Gabriela Gago, Hugo Gramajo and Héctor M. Alvarez

      Version of Record online: 25 NOV 2016 | DOI: 10.1111/mmi.13564

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      The ability to accumulate significant amounts of triacylglycerols by rhodococci requires a special metabolic network involving concerted reactions and pathways, and a specific regulatory circuit for the control and coordination of the process. In this study, we identified a transcriptional regulator that contributes to control of nitrogen metabolism and the modulation of lipid biosynthesis and triacylglycerol accumulation in R. jostii RHA1 under nitrogen starvation conditions.

    3. Cryptic purine transporters in Aspergillus nidulans reveal the role of specific residues in the evolution of specificity in the NCS1 family

      Georgia Sioupouli, George Lambrinidis, Emmanuel Mikros, Sotiris Amillis and George Diallinas

      Version of Record online: 25 NOV 2016 | DOI: 10.1111/mmi.13559

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      • Characterization of Fcy-like transporters in Aspergillus nidulans.
      • FcyD is a highly specific adenine transporter and FcyE contributes to 8-azaguanine uptake.
      • Mutational analysis, homology modelling and substrate docking showed that Leu356 and Ser359 in transmembrane segment 8 (TMS8) of FcyD are critical for transport kinetics and specificity, while Phe167 and Ser171 in TMS3 are important for function.
    4. Maf1 is a negative regulator of transcription in Trypanosoma brucei

      Gabriela Romero-Meza, Daniel E. Vélez-Ramírez, Luis E. Florencio-Martínez, Fiordaliso C. Román-Carraro, Rebeca Manning-Cela, Rosaura Hernández-Rivas and Santiago Martínez-Calvillo

      Version of Record online: 25 NOV 2016 | DOI: 10.1111/mmi.13568

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      Maf1 is a negative regulator of transcription conserved from yeast to human. In this work we characterized Maf1 in Trypanosoma brucei (TbMaf1), an early-diverging eukaryote. Our data show that TbMaf1 is involved in the control of cell growth in procyclic forms of T. brucei and that it represses transcription of Pol III-dependent genes. Our results also reveal that TbMaf1 regulates transcription of some Pol I- and Pol II-dependent genes.

    5. ProP-ProP and ProP-phospholipid interactions determine the subcellular distribution of osmosensing transporter ProP in Escherichia coli

      Tatyana Romantsov, Doreen E. Culham, Tavia Caplan, Jennifer Garner, Robert S. Hodges and Janet M. Wood

      Version of Record online: 25 NOV 2016 | DOI: 10.1111/mmi.13569

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      Osmosensing transporter ProP mediates osmolyte uptake to protect bacteria from osmotically-induced dehydration. ProP activity is anionic lipid-dependent and ProP concentrates at the poles of Escherichia coli cells in a cardiolipin-dependent manner. This work suggests that polar localization of ProP results from association of its C-terminal domain with the anionic lipid-enriched membrane at the cell poles. The coiled-coil present on only some orthologues renders that phenomenon CL-dependent.

    6. Starvation and recovery in the deep-sea methanotroph Methyloprofundus sedimenti

      Patricia L. Tavormina, Matthias Y. Kellermann, Chakkiath Paul Antony, Elitza I. Tocheva, Nathan F. Dalleska, Ashley J. Jensen, David L. Valentine, Kai-Uwe Hinrichs, Grant J. Jensen, Nicole Dubilier and Victoria J. Orphan

      Version of Record online: 22 NOV 2016 | DOI: 10.1111/mmi.13553

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      The stress response of a deep-sea methane oxidizing bacterium is reported in this study. During starvation, cells display certain hallmark features of stress including reduced cytoplasmic volume. Unusual features were also detected during starvation, including maintenance of certain membrane characteristics and an increase in the abundance of select gene transcripts. Shown is an cryotomographic slice of a deep-sea methanotrophic cell after four days of methane starvation.

    7. Salmonella enterica synthesizes 5,6-dimethylbenzimidazolyl-(DMB)-α-riboside. Why some Firmicutes do not require the canonical DMB activation system to synthesize adenosylcobalamin

      Theodoric A. Mattes and Jorge C. Escalante-Semerena

      Version of Record online: 22 NOV 2016 | DOI: 10.1111/mmi.13555

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      Some Firmicutes have a two-protein system that can scavenge α-ribazole and convert it to α-ribazole-5′-phosphate. Expression of the Firmicute system in Salmonella revealed the existence of an unknown pathway for the synthesis of the α-ribazole in this bacterium. Knowledge about how Salmonella uses the Firmicute enzyme system provides insights into how these microorganisms synthesize adenosylcobalamin in the absence of a canonical lower ligand base activation system and an exogenous source of α-ribazole.

    8. Discovery of McrA, a master regulator of Aspergillus secondary metabolism

      C. Elizabeth Oakley, Manmeet Ahuja, Wei-Wen Sun, Ruth Entwistle, Tomohiro Akashi, Junko Yaegashi, Chun-Jun Guo, Gustavo C. Cerqueira, Jennifer Russo Wortman, Clay C. C. Wang, Yi-Ming Chiang and Berl R. Oakley

      Version of Record online: 14 NOV 2016 | DOI: 10.1111/mmi.13562

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      Using a new genetic screen, we have identified a conserved but uncharacterized gene that negatively regulates secondary metabolite production in the filamentous fungus Aspergillus nidulans. Deletion of the gene increases production of a large number of secondary metabolites including novel compounds and it alters the transcription of a large number of genes including many involved in secondary metabolite biosynthesis. Deletions of this gene and its homologs may be valuable tools for secondary metabolite discovery.

    9. You have full text access to this OnlineOpen article
      ArnS, a kinase involved in starvation-induced archaellum expression

      M. Florencia Haurat, Ana Sofia Figueiredo, Lena Hoffmann, Lingling Li, Katharina Herr, Amanda J. Wilson, Morgan Beeby, Jörg Schaber and Sonja-Verena Albers

      Version of Record online: 14 NOV 2016 | DOI: 10.1111/mmi.13550

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      In S. acidocaldarius the archaeal motility organelle (archaellum) is regulated by a complex phosphorylation dependent regulatory network. Here, we employ in vivo experiments and mathematical models to understand the dynamics of this network and the role the protein kinase ArnS plays herein.

    10. Clathrin localization and dynamics in Aspergillus nidulans

      Z. Schultzhaus, T. B. Johnson and B. D. Shaw

      Version of Record online: 14 NOV 2016 | DOI: 10.1111/mmi.13557

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      Aspergillus nidulans clathrin heavy chain ClaH localizes to three distinct structures. These include a dynamic plaque at the endocytic collar, domains on the late Golgi that increasingly recruit clathrin through the Golgi lifetime before dissipating at vesiculation into post-Golgi, and mobile puncta that travel long distances on microtubules in apical and subapical regions but are generally distinct from early endosomes.

  4. MicroReview

    1. You have free access to this content
      Dual-function small regulatory RNAs in bacteria

      Matthias Gimpel and Sabine Brantl

      Version of Record online: 14 NOV 2016 | DOI: 10.1111/mmi.13558

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      Dual-function sRNAs are a subgroup of small regulatory RNAs that act on the one hand as base-pairing sRNAs to inhibit or activate target gene expression and on the other hand as peptide-encoding mRNAs. The mechanisms of action of the currently known five dual-function sRNAs are represented schematically.

  5. Research Articles

    1. The Group A Streptococcus serotype M2 pilus plays a role in host cell adhesion and immune evasion

      Jia-Yun C. Tsai, Jacelyn M. S. Loh, Fiona Clow, Natalie Lorenz and Thomas Proft

      Version of Record online: 14 NOV 2016 | DOI: 10.1111/mmi.13556

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      The Group A Streptococcus serotype M2 strain carries a pilus encoded in the FCT-6 region. This pilus type has never been characterised before. We found that in addition to its function as an adhesive structure, the FCT-6 pilus also plays a role in immune evasion. This appears to be mediated mainly by the backbone pilin which was shown to bind fibrinogen.

    2. Structural basis for the transcriptional repressor NicR2 in nicotine degradation from Pseudomonas

      Kunzhi Zhang, Geng Wu, Hongzhi Tang, Chuanming Hu, Ting Shi and Ping Xu

      Version of Record online: 13 NOV 2016 | DOI: 10.1111/mmi.13548

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      NicR2 contains a pocket to selectively recognize its inducer, thus unties the transcription of nic2 cluster. The key residues from both HTH motif and N-terminal extension of NicR2 participate in the association with DNA and repress the transcription of nic2 cluster. Our structural and biochemical investigations unravel how NicR2 selectively recognizes HSP and DNA, and provide new insights into the TetR family of repressors.

    3. Sinorhizobium meliloti chemotaxis to quaternary ammonium compounds is mediated by the chemoreceptor McpX

      Benjamin A. Webb, K. Karl Compton, Rafael Castañeda Saldaña, Timofey D. Arapov, W. Keith Ray, Richard F. Helm and Birgit E. Scharf

      Version of Record online: 11 NOV 2016 | DOI: 10.1111/mmi.13561

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      The alfalfa seed germination process releases quaternary ammonium compounds (QACs) into the soil, which were confirmed as attractants for the microsymbiont Sinorhizobium meliloti. The canonical bacterial chemoreceptor for QAC sensing was identified to be McpX, which binds ligands directly. These attractants elicit stronger chemotaxic responses than the more abundant amino acid proline, suggesting that genetic modification of alfalfa for an increased QAC release can provide greater attraction of the microsymbiont to the host.

    4. Bordetella adenylate cyclase toxin interacts with filamentous haemagglutinin to inhibit biofilm formation in vitro

      Casandra Hoffman, Joshua Eby, Mary Gray, F. Heath Damron, Jeffrey Melvin, Peggy Cotter and Erik Hewlett

      Version of Record online: 3 NOV 2016 | DOI: 10.1111/mmi.13551

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      The catalytic domain (AC domain) of Bordetella Adenylate Cyclase Toxin (ACT) interacts with the distal tip of filamentous haemagglutinin, the mature C-terminal domain with approximately 650 nM affinity. This interaction results in the inhibition of biofilm formation by B. pertussis and B. bronchiseptica in vitro. Despite the AC domain being necessary and sufficient for inhibition, the catalytic activity of ACT is not required for biofilm inhibition.

    5. Structurally diverse dehydroshikimate dehydratase variants participate in microbial quinate catabolism

      James Peek, Joseph Roman, Graham R. Moran and Dinesh Christendat

      Version of Record online: 3 NOV 2016 | DOI: 10.1111/mmi.13542

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      The Pseudomonas protein, QuiC1, is a novel dimeric ‘two-domain’ dehydroshikimate dehydratase (DSD) that participates in the catabolism of quinate and shikimate. The Nterminal half of the protein is associated with DSD activity while an enigmatic Cterminal domain resembles hydroxyphenylpyruvate dioxygenase. At least four DSD subclasses can now be identified among bacteria and fungi, each with distinct structural properties.

    6. Bacillus subtilis MntR coordinates the transcriptional regulation of manganese uptake and efflux systems

      Xiaojuan Huang, Jung-Ho Shin, Azul Pinochet-Barros, Tina T. Su and John D. Helmann

      Version of Record online: 2 NOV 2016 | DOI: 10.1111/mmi.13554

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      The dimeric MntR metalloregulatory protein monitors intracellular Mn(II) status in B. subtilis. As Mn(II) levels increase, MntR represses the expression of two Mn(II) uptake systems (MntH and MntABCD) and then activates the expression of two efflux systems (MneP and MneS).

    7. Identification of aminopyrimidine-sulfonamides as potent modulators of Wag31-mediated cell elongation in mycobacteria

      Vinayak Singh, Neeraj Dhar, János Pató, Gaëlle S. Kolly, Jana Korduláková, Martin Forbak, Joanna C. Evans, Rita Székely, Jan Rybniker, Zuzana Palčeková, Júlia Zemanová, Isabella Santi, François Signorino-Gelo, Liliana Rodrigues, Anthony Vocat, Adrian S. Covarrubias, Monica G. Rengifo, Kai Johnsson, Sherry Mowbray, Joseph Buechler, Vincent Delorme, Priscille Brodin, Graham W. Knott, José A. Aínsa, Digby F. Warner, György Kéri, Katarína Mikušová, John D. McKinney, Stewart T. Cole, Valerie Mizrahi and Ruben C. Hartkoorn

      Version of Record online: 29 OCT 2016 | DOI: 10.1111/mmi.13535

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      Here a potent anti-tuberculosis compound is described (APYS1), with resistant isolates carrying clustered mutations in the elongation scaffolding protein: Wag31. Visualisation of the impact of APYS1 on Mycobacterium tuberculosisby microscopy reveals gross malformations of the bacterial pole, a phenomenon similar to that observedupon genetic downregulation of wag31. Further validation demonstrates that APYS1 has an atypical mechanism of action, not directly targeting Wag31, but perhaps an associated protein-protein interaction.

    8. Plasticity of archaeal C/D box sRNA biogenesis

      Vanessa Tripp, Roman Martin, Alvaro Orell, Omer S. Alkhnbashi, Rolf Backofen and Lennart Randau

      Version of Record online: 29 OCT 2016 | DOI: 10.1111/mmi.13549

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      C/D box sRNAs constitute one of the most abundant RNA families in Archaea and are used to guide methylation of target RNA molecules. We analyzed the biogenesis of this RNA family and observed its independence of the genetic context. This plasticity of C/D box sRNA biogenesis is suggested to enable their accelerated evolution and allow for adjustments of the RNA modification landscape. Graphical Abstract 59×44mm (300 × 300 DPI)

    9. A novel glycan modifies the flagellar filament proteins of the oral bacterium Treponema denticola

      Kurni Kurniyati, John F. Kelly, Evgeny Vinogradov, Anna Robotham, Youbing Tu, Juyu Wang, Jun Liu, Susan M. Logan and Chunhao Li

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/mmi.13544

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      Swimming with sugar: We demonstrate that the flagellar filament proteins of oral bacterium Treponema denticola are modified with a novel glycan (a C7-acylated pseudaminic acid derivative, m/z 451.2) and that such a modification is essential for flagellar assembly and motility.

    10. Regulation of katanin activity in the ciliate Tetrahymena thermophila

      Ewa Waclawek, Ewa Joachimiak, Malgorzata Hanna Hall, Hanna Fabczak and Dorota Wloga

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/mmi.13547

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      Katanin, a microtubule severing protein functions as a heterodimer of a catalytic subunit, p60, and a regulatory subunit, a WD40 repeat protein, p80.We found that prolonged overproduction of the p80 subunit in Tetrahymena cells partly phenocopies knockout of the catalytic subunit, p60. Thus, our data support a dual character of KAT3p as both an activator and a repressor of KAT1p.

    11. Glucose deprivation induced upregulation of phosphoenolpyruvate carboxykinase modulates virulence in Leishmania donovani

      Savita Saini, Ayan Kumar Ghosh, Ruby Singh, Sushmita Das, Kumar Abhishek, Ajay Kumar, Sudha Verma, Abhishek Mandal, Abul Hasan Sardar, Bidyut Purkait, Ashish Kumar, Kislay Kumar Sinha and Pradeep Das

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/mmi.13534

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      This investigation indicates that glucose starvation increase the gluconeogenic flux in L.donovani with the involvement of LdPEPCK, to harness alternative energy source which simultaneously, enhances its virulence with induction of autophagy and intracellular ROS generation, that increases survival inside macrophage after infection.

    12. You have full text access to this OnlineOpen article
      The Paracoccus denitrificans NarK-like nitrate and nitrite transporters—probing nitrate uptake and nitrate/nitrite exchange mechanisms

      Alan D. Goddard, Shilpa Bali, Despoina A.I. Mavridou, Victor M. Luque-Almagro, Andrew J. Gates, M. Dolores Roldán, Simon Newstead, David J. Richardson and Stuart J. Ferguson

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/mmi.13546

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      NarK-like proteins have been proposed to function either as nitrate/proton symporters or as nitrate/nitrite exchangers. According to functional studies, NasA and the NarK1 domain of NarK in Paracoccus denitrificans are examples of the former and the NarK2 domain of the latter. Structural data are not readily consistent with this classification thus the possibility that all NarK-like proteins have a nitrate/nitrite exchange function, with nitrite being imported by the nitrite channel NasH when required, is discussed.

    13. Utilization of glycerophosphodiesters by Staphylococcus aureus

      Ana Maria Jorge, Jonathan Schneider, Sandra Unsleber, Nadine Göhring, Christoph Mayer and Andreas Peschel

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/mmi.13552

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      Staphylococcus aureus can use glycerophosphodiesters (GroPC, GroPI, GroPS, GroPE, and GroPG) obtained after deacylation of the corresponding phospholipids phosphatidylcholine, phosphatidylinositol, phosphatidylserine, phosphatidylethanolamine, and phosphatidylglycerol. Secreted GlpQ from S. aureus cleaves the glycerophospho bond releasing an alcohol and glycerol-3-phosphate (Gro-3P), which can be used by S. aureus as a carbon, phosphate and energy source, and in many physiological processes.

    14. Identification of pneumococcal proteins that are functionally linked to penicillin-binding protein 2b (PBP2b)

      Daniel Straume, Gro Anita Stamsås, Kari Helene Berg, Zhian Salehian and Leiv Sigve Håvarstein

      Version of Record online: 27 OCT 2016 | DOI: 10.1111/mmi.13543

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      In the present paper, we show that deletion or depletion of PBP2b, RodA, MreD, DivIVA or Spr0777 induce very similar phenotypic changes in Streptococcus pneumoniae strain R6, providing strong evidence that these proteins cooperate to build a functional elongasome. DivIVA targets negatively curved membranes. It is therefore likely that the function of DivIVA is to correctly localize the elongasome at the highly negatively curved membrane region between the septal and lateral cell wall.

    15. The putative Walker A and Walker B motifs of Rrp2 are required for the growth of Borrelia burgdorferi

      Zhiming Ouyang and Jianli Zhou

      Version of Record online: 26 OCT 2016 | DOI: 10.1111/mmi.13545

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      Rrp2 acts in concert with BosR to activate σ54-dependent rpoS transcription in Borrelia burgdorferi. In contrast to canonical bacterial enhancer binding proteins, Rrp2 is essential for the growth of B. burgdorferi. We demonstrate that the Walker A and B motifs constituting ATP binding and hydrolysis activities of Rrp2 are required for borrelial growth, suggesting that the Walker motifs are involved in Rrp2's control over another unknown RpoS-independent gene product(s) associated with cell replication.

    16. Staphylococcus aureus SufT: an essential iron-sulphur cluster assembly factor in cells experiencing a high-demand for lipoic acid

      Ameya A. Mashruwala, Christina A. Roberts, Shiven Bhatt, Kerrie L. May, Ronan K. Carroll, Lindsey N. Shaw and Jeffrey M. Boyd

      Version of Record online: 21 OCT 2016 | DOI: 10.1111/mmi.13539

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      Cells contain iron-sulphur (Fe-S) cluster utilizing proteins and proteins that facilitate cluster assembly. Lipoic acid (LA) is a product of the Fe-S cluster dependent enzyme LipA. The SufT Fe-S cluster assembly factor is essential in cells experiencing a high demand for lipoamide-dependent enzymes. We propose that the demand for products of Fe-S enzymes is a factor governing the usage of one Fe-S assembly factor over another in the maturation of apo-proteins.

    17. Investigation on the anaerobic propionate degradation by Escherichia coli K12

      Francesca M. Simonte, Andreas Dötsch, Lisete Galego, Cecilia Arraiano and Johannes Gescher

      Version of Record online: 20 OCT 2016 | DOI: 10.1111/mmi.13541

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      Escherichia coli K12 is able to utilize propionate as carbon and energy source only under oxic conditions. The propionate degradation pathway, also called 2-methylcitrate cycle, is encoded by the prp-operon. In this study, we revealed a posttranscriptional regulation of the prp-operon under anoxic conditions. Different lines of evidence suggest a pivotal role of RNase R for the stability of the corresponding mRNA to the prp-gene cluster. Although the data suggest a direct hydrolysis of the mRNA by RNase R, we cannot exclude a further indirect posttranscriptional regulation (indicated by an x), which is mediated by the RNA hydrolyzing enzyme.

    18. Role of EhRab7A in phagocytosis of type 1 fimbriated E. coli by Entamoeba histolytica

      Kuldeep Verma, Tomoyoshi Nozaki and Sunando Datta

      Version of Record online: 20 OCT 2016 | DOI: 10.1111/mmi.13533

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      Members of Rab GTPase family are involved in various stages of phagocytosis. Rab7 subfamily is known to control the late stage of phagocytosis in higher eukaryotes. We demonstrated that the function of EhRab7A is indispensable during the early and late stages of type 1 Escherichia coli phagocytosis in Entamoeba histolytica. The internalization process was found to be actin independent in the parasite.

    19. Regulation, sensory domains and roles of two Desulfovibrio desulfuricans ATCC27774 Crp family transcription factors, HcpR1 and HcpR2, in response to nitrosative stress

      Ian T. Cadby, Susan A. Ibrahim, Matthew Faulkner, David J. Lee, Douglas Browning, Stephen J. Busby, Andrew L. Lovering, Melanie R. Stapleton, Jeffrey Green and Jeffrey A. Cole

      Version of Record online: 20 OCT 2016 | DOI: 10.1111/mmi.13540

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      Abbreviated abstract

      Some sulfate reducing bacteria isolated from the human body contain two Crp/Fnr family transcription factors, HcpR1 and HcpR2, that use different sensory mechanisms to regulate their defense against NO-induced nitrosative stress. We propose that acquisition of an additional hcpR gene, possibly from another member of the gut microbiome, permits specialisation of these regulators to fulfill different roles under selective pressure in the gastro-intestinal tract where they are exposed to multiple sources of nitrosative stress.

    20. ClpAP is an auxiliary protease for DnaA degradation in Caulobacter crescentus

      Jing Liu, Laura I. Francis, Kristina Jonas, Michael T. Laub and Peter Chien

      Version of Record online: 17 OCT 2016 | DOI: 10.1111/mmi.13537

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      In Caulobacter crescentus, levels of the replication initiator protein DnaA are known to be controlled through proteolysis by the Lon protease. In this work, we show that the ClpAP protease also contributes to DnaA degradation in a process inhibited by the ClpS adaptor. ClpAP degrading DnaA is particularly important during extended growth and entry into the stationary phase. Having two proteolytic pathways controlling an essential replication factor is an excellent strategy to ensure robust control under different growth conditions.

    21. Developmental change in translation initiation alters the localization of a common microbial protein necessary for Toxoplasma chronic infection

      Kathryn Milligan-Myhre, Sarah K. Wilson and Laura J. Knoll

      Version of Record online: 14 OCT 2016 | DOI: 10.1111/mmi.13538

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      A Toxoplasma mutant that is disrupted in a protein highly conserved in microbes but is not present in humans, produces fewer cysts in mouse brains during chronic infection. In cell culture, translation of this protein initiates at the third methionine to produce a 25 kDa form, whereas in brain cysts translation begins at the first methionine to produce a 51 kDa form that is secreted from the parasites and localizes to the cyst wall.

  6. MicroReview

    1. To ∼P or Not to ∼P? Non-canonical activation by two-component response regulators

      Stuti K. Desai and Linda J. Kenney

      Version of Record online: 11 OCT 2016 | DOI: 10.1111/mmi.13532

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      A majority of response regulators are activated by a phosphorylation-driven switch in response to environmental sensing by membrane-bound sensor kinases. In this microreview, we describe examples of non-canonical signaling involving unphosphorylated or unphosphorylable response regulators across bacterial phyla. Some of these non-canonical response regulators bind to silenced promoter sequences as homo or heterodimers and mediate transcriptional activation by anti-silencing.

  7. Research Articles

    1. A functional link between hyphal maintenance and quorum sensing in Candida albicans

      Melanie Polke, Marcel Sprenger, Kirstin Scherlach, María Cristina Albán-Proaño, Ronny Martin, Christian Hertweck, Bernhard Hube and Ilse D. Jacobsen

      Version of Record online: 11 OCT 2016 | DOI: 10.1111/mmi.13526

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      The deletion of the Candida albicans EED1 gene (eed1Δ), which is essential for hyphal maintenance, leads to the unique phenotype of both, an increased sensitivity to and increased production of the quorum sensing molecule farnesol. The enhanced farnesol signaling activity in eed1Δ is independent of cAMP signaling, promotes the reverse morphogenesis under hypha-inducing conditions without inducing cell death, and contributes to the hyphal maintenance defect of the mutant.

    2. You have full text access to this OnlineOpen article
      Off-pathway assembly of fimbria subunits is prevented by chaperone CfaA of CFA/I fimbriae from enterotoxigenic E. coli

      Rui Bao, Yang Liu, Stephen J. Savarino and Di Xia

      Version of Record online: 7 OCT 2016 | DOI: 10.1111/mmi.13530

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      The colonization factor antigen I (CFA/I) pili are archetypal of a group of human-specific enterotoxigenic E. coli (ETEC) and are assembled via the alternate chaperone-usher pathway. Here, we present the structure of the chaperone CfaA in complex with subunit CfaB and demonstrate that the role of CfaA in CFA/I pilus assembly is to avoid off pathway self-polymerization of the subunit CfaB (dotted arrows).

    3. The bacteriophage-derived transcriptional regulator, LscR, activates the expression of levansucrase genes in Pseudomonas syringae

      Khaled Abdallah, Katharina Hartman, Daniel Pletzer, Daria Zhurina and Matthias S. Ullrich

      Version of Record online: 7 OCT 2016 | DOI: 10.1111/mmi.13536

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      Bacterial blight pathogen of soybean, Pseudomonas syringae pv. glycinea PG4180, produces the exopolymer levan under sucrose-rich conditions using the enzyme levansucrase. By functional screening of the PG4180 genome for regulators of levansucrase expression, a prophage-borne transcriptional activator termed LscR was identified and shown to physically interact with the upstream region of levansucrase genes. A lscR-deficient mutant of PG4180 showed a clear levan-negative phenotype (right) compared to the wildtype (left) when grown on sucrose-rich agar medium.

    4. Single-molecule dynamics of the molecular chaperone trigger factor in living cells

      Feng Yang, Tai-Yen Chen, Łukasz Krzemiński, Ace George Santiago, Won Jung and Peng Chen

      Version of Record online: 30 SEP 2016 | DOI: 10.1111/mmi.13529

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      In bacteria, trigger factor (TF) is the molecular chaperone that interacts with the ribosome to assist the folding of nascent polypeptides. We use single-molecule tracking, photoconvertible bimolecular fluorescence complementation and genetic manipulations to probe the function and dynamics of TF and TF2 dimers in live E. coli cells. We gain insights into how TF and TF2 interact with the ribosome, the polypeptides, the DnaK/DnaJ chaperones, or the signal recognition particle in living cells.

  8. MicroReview

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      Atypical modes of bacterial histidine kinase signaling

      Jonathan W. Willett and Sean Crosson

      Version of Record online: 30 SEP 2016 | DOI: 10.1111/mmi.13525

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      Recent studies have defined atypical modes of bacterial histidine kinase interactions, which enable complex signal integration. We highlight some of these unusual examples and discuss their significance within this MicroReview.

  9. Research Articles

    1. The SAGA complex in the rice pathogen Fusarium fujikuroi: structure and functional characterization

      Sarah M. Rösler, Katharina Kramer, Iris Finkemeier, Hans-Ulrich Humpf and Bettina Tudzynski

      Version of Record online: 30 SEP 2016 | DOI: 10.1111/mmi.13528

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      The Spt-Ada-Gcn5 acetyltransferase complex is highly conserved in the rice pathogen Fusarium fujikuroi, except for the missing DUBm module and Chd1 known from Saccharomyces cerevisiae. We show that Gcn5 is essential for the acetylation of several lysine residues of histone 3, the formation of conidia and wild type-like growth in F. fujikuroi. A genome-wide microarray analysis revealed differential expression of genes mainly involved in secondary metabolism, transport and gene regulation by GCN5 deletion.

    2. Characterization of secreted sphingosine-1-phosphate lyases required for virulence and intracellular survival of Burkholderia pseudomallei

      Rafael Custódio, Christopher J. McLean, Andrew E. Scott, Jonathan Lowther, Amanda Kennedy, David J. Clarke, Dominic J. Campopiano, Mitali Sarkar-Tyson and Alan R. Brown

      Version of Record online: 26 SEP 2016 | DOI: 10.1111/mmi.13531

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      Following phagocytosis, sphingosine-1-phosphate (S1P) lyases are secreted by Burkholderia pseudomallei (1). These S1P lyases catalyse the irreversible degradation of S1P, a bioactive sphingolipid metabolite that promotes phagosome maturation (2). These bacterial S1P lyases promote escape from endocytic vacuoles and subsequent intracellular replication (3). S1P lyase-deficient Burkholderia are unable to evade the maturing phagosome and display attenuated virulence. Treatment of infected macrophages with exogenous S1P circumvents the activity of the bacterial S1P lyases, enhancing bacterial killing.


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