Molecular Microbiology

Cover image for Vol. 100 Issue 5

Accepted Articles (Accepted, unedited articles published online and citable. The final edited and typeset version of record will appear in future.)

Edited By: John D. Helmann

Impact Factor: 4.419

ISI Journal Citation Reports © Ranking: 2014: 20/119 (Microbiology); 66/290 (Biochemistry & Molecular Biology)

Online ISSN: 1365-2958

Associated Title(s): Cellular Microbiology


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  1. Microreview

    1. Interplay of regulatory RNAs and mobile genetic elements in enteric pathogens

      Kathrin S. Fröhlich and Kai Papenfort

      Accepted manuscript online: 27 MAY 2016 06:55PM EST | DOI: 10.1111/mmi.13428

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      Abbreviated Summary

      Small, regulatory RNAs (sRNAs) serve important roles in bacterial gene regulation. Frequently, sRNAs also function as key players in the interaction of core genome elements and horizontally-acquired DNA. This MicroReview focuses on sRNAs functioning between existing and newly obtained genetic material in enterobacterial pathogens.

  2. Research Articles

    1. Glucose induces delocalization of a flagellar biosynthesis protein from the flagellated pole

      Soyoung Park, Young-Ha Park, Chang-Ro Lee, Yeon-Ran Kim and Yeong-Jae Seok

      Accepted manuscript online: 24 MAY 2016 02:20AM EST | DOI: 10.1111/mmi.13424

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      Making a right decision to stay or move is critical for survival in a changing environment. Here we identify a novel mechanism for glucose-dependent on-off switching of flagellar synthesis in Vibrio vulnificus: When enzyme IIAGlc of the bacterial PEP:carbohydrate phosphotransferase system is dephosphorylated in the presence glucose, it delocalizes a protein required for flagellar biosynthesis from the flagellated pole. This leads to a loss of motility and enables bacteria to stay in a favorable habitat.

    2. RflM mediates target specificity of the RcsCDB phosphorelay system for transcriptional repression of flagellar synthesis in Salmonella enterica

      Caroline Kühne, Hanna M. Singer, Eva Grabisch, Luca Codutti, Teresa Carlomagno, Andrea Scrima and Marc Erhardt

      Accepted manuscript online: 20 MAY 2016 09:06AM EST | DOI: 10.1111/mmi.13427

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      In Salmonella, biosynthesis of flagella is subject to strict regulatory control. A novel flagellar-specific auxiliary protein, RflM, mediates target specificity of the global RcsCDB phosphorelay system for repression of the flagellar master regulator operon, flhDC. The coordinated action of the flagellar-dependent regulator RflM and the global Rcs system allows Salmonella to fine-tune the initiation of flagellar synthesis in response to diverse environmental conditions.

    3. Elucidation of a mechanism of oxidative stress regulation in Francisella tularensis live vaccine strain

      Zhuo Ma, Vincenzo C. Russo, Seham M. Rabadi, Yu Jen, Sally V. Catlett, Chandra Shekhar Bakshi and Meenakshi Malik

      Accepted manuscript online: 20 MAY 2016 09:06AM EST | DOI: 10.1111/mmi.13426

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      Abbreviated Summary

      Francisella tularensis is a highly virulent human pathogen. The mechanism of regulation of the oxidative stress response that facilitates the survival of F. tularensis in phagocytic cells is not known. This study characterized the role of an oxidative stress regulator, OxyR, in F. tularensis LVS. The results demonstrate that OxyR is an important virulence factor and transcriptional regulator of the oxidative stress response of F. tularensis.

    4. Integration Host Factor and LuxR synergistically bind DNA to co-activate quorum-sensing genes in Vibrio harveyi

      Ryan R. Chaparian, Stephen G. Olney, Christine M. Hustmyer, Dean A. Rowe-Magnus and Julia C. van Kessel

      Accepted manuscript online: 18 MAY 2016 11:29AM EST | DOI: 10.1111/mmi.13425

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      The bacterial communication system called quorum sensing controls group behaviors in Vibrio harveyi through the master transcription factor LuxR. LuxR directly interacts with Integration Host Factor (IHF), a nucleoid-associated protein and global transcription regulator, and LuxR and IHF co-regulate 118 genes. LuxR and IHF synergistically bind DNA to control the timing and level of expression of quorum-sensing genes, including the bioluminescence and osmotic stress response genes.

    5. The function of the PduJ microcompartment shell protein is determined by the genomic position of its encoding gene

      Chiranjit Chowdhury, Sunny Chun, Michael R. Sawaya, Todd O. Yeates and Thomas A. Bobik

      Accepted manuscript online: 14 MAY 2016 09:00AM EST | DOI: 10.1111/mmi.13423

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      Deletion of the pduA gene impairs the function of the 1,2-propanediol utilization microcompartment of Salmonella (Pdu MCP). When PduJ (a close homologue of PduA) is expressed from plasmid, it does not correct the defects of a ΔpduA mutant. However, when PduJ is expressed from the pduA chromosomal locus, it restores normal MCP function. Thus, we propose that the function of the pduJ gene is dependent on the genomic position of its encoding gene.

    6. Molybdate uptake by Agrobacterium tumefaciens correlates with the cellular molybdenum cofactor status

      Marie-Christine Hoffmann, Koral Ali, Marleen Sonnenschein, Laura Robrahn, Daria Strauss, Franz Narberhaus and Bernd Masepohl

      Accepted manuscript online: 14 MAY 2016 09:00AM EST | DOI: 10.1111/mmi.13421

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      Most bacteria synthesize high-affinity molybdate (Mo) transporters, ModABC, under Mo-limiting conditions. Under Mo-replete conditions, modABC transcription is repressed by molybdate-binding ModE regulators in Escherichia coli and other bacteria. Here, we characterized a ModE regulator lacking a molybdate-binding domain (ModES) from Agrobacterium tumefaciens. We provide first evidence that modABC repression requires the molybdenum cofactor, Moco, rather than directly responding to molybdate in A. tumefaciens and possibly also in other species lacking a full-length ModE regulator.

    7. Rearrangements of α-helical structures of FlgN chaperone control the binding affinity for its cognate substrates during flagellar type III export

      Miki Kinoshita, Yuki Nakanishi, Yukio Furukawa, Keiichi Namba, Katsumi Imada and Tohru Minamino

      Accepted manuscript online: 13 MAY 2016 12:40AM EST | DOI: 10.1111/mmi.13415

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      The structure and structure-based functional analyses reveal that the N-loop between α1 and α2 of FlgN acts as a structural switch for the rearrangement of three α helices to control the binding affinity of helix α3 for FlgK.

  3. Microreviews

    1. Non-canonical roles of tRNAs and tRNA mimics in bacterial cell biology

      Assaf Katz, Sara Elgamal, Andrei Rajkovic and Michael Ibba

      Accepted manuscript online: 12 MAY 2016 04:16AM EST | DOI: 10.1111/mmi.13419

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      The main function of tRNAs is usually considered to be the transfer of activated amino acids from aminoacyl-tRNA synthetases to nascent peptides at the ribosome. Consequentially, tRNAs are considered essential in the evolution of organisms that use proteins instead of RNAs as enzymes. Nevertheless, tRNAs also have several functions beyond translation. Here we discuss how tRNAs were coopted from main in translation role into other metabolic, regulatory and genomic functions.

  4. Research Articles

    1. The Saccharomyces cerevisiae Ptc1 protein phosphatase attenuates G2-M cell cycle blockage caused by activation of the cell wall integrity pathway

      Laura Tatjer, Asier González, Albert Serra-Cardona, Anna Barceló, Antonio Casamayor and Joaquín Ariño

      Accepted manuscript online: 12 MAY 2016 04:16AM EST | DOI: 10.1111/mmi.13416

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      Activation of the cell wall integrity pathway leads to phosphorylation of Cdc28 and delay in cell cycle progression at the G2-M transition. By dephosphorylating and inhibiting the MAPK kinase Mkk1, the Ptc1 phosphatase avoids excessive activation of the Sl2 MAPK and contributes to resume cell cycle.

    2. A response regulator promotes Francisella tularensis intramacrophage growth by repressing an anti-virulence factor

      Kathryn M. Ramsey and Simon L. Dove

      Accepted manuscript online: 12 MAY 2016 04:16AM EST | DOI: 10.1111/mmi.13418

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      It was thought that the response regulator PmrA was essential for the intramacrophage growth of Francisella tularensis because it positively regulated the expression of type VI secretion genes present on the so-called Francisella Pathogenicity Island. We show instead that PmrA promotes intramacrophage growth by repressing a gene that encodes a previously unknown anti-virulence factor. This PmrA-repressed gene is the first F. tularensis gene we are aware of that can interfere with intramacrophage growth and survival.

    3. Structural insights into the inhibition mechanism of bacterial toxin LsoA by bacteriophage antitoxin Dmd

      Hua Wan, Yuichi Otsuka, Zeng-Qiang Gao, Yong Wei, Zhen Chen, Michiaki Masuda, Tetsuro Yonesaki, Heng Zhang and Yu-Hui Dong

      Accepted manuscript online: 12 MAY 2016 04:15AM EST | DOI: 10.1111/mmi.13420

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      The antitoxin Dmd from T4 phage is inserted into the deep groove between the N-terminal repeated domain (NRD) and the Dmd-binding domain (DBD) of Escherichia coli toxin LsoA. The conserved Dmd-interacting residues in this groove are vital for LsoA toxicity generated by its RNase activity. Therefore, Dmd can recognize LsoA and inhibit its toxicity by occupying the active site via substrate RNA mimicry.

    4. Transcriptome and proteome analyses and the role of atypical calpain protein and autophagy in the spliced leader silencing (SLS) pathway in Trypanosoma brucei

      Ronen Hope, Katarina Egarmina, Konstantin Voloshin, Hiba Waldman Ben-Asher, Shai Carmi, Dror Eliaz, Yaron Drori and Shulamit Michaeli

      Accepted manuscript online: 10 MAY 2016 03:46AM EST | DOI: 10.1111/mmi.13417

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      Spliced leader silencing (SLS) is a stress induced mechanism in Trypanosoma brucei which stops SL RNA transcription and trans-splicing. The study describes the proteome and transcriptome of SLS induced cells and identified a key protein in SLS signaling, a calpain like-protease which is important for transmitting the stress signal to the nucleus and for dying in a controlled way. Autophagy also contributes to programmed cell death induced by SLS induction.

  5. Microreview

    1. The magic dance of the alarmones (p)ppGpp

      Wieland Steinchen and Gert Bange

      Accepted manuscript online: 5 MAY 2016 10:21AM EST | DOI: 10.1111/mmi.13412

  6. Research Articles

    1. RNase E-based Degradosome Modulates Polyadenylation of mRNAs after Rho-independent Transcription Terminators in Escherichia coli

      Kristen B. Mildenhall, Nicholas Wiese, Daewhan Chung, Valerie F. Maples, Bijoy K. Mohanty and Sidney R. Kushner

      Accepted manuscript online: 5 MAY 2016 03:45AM EST | DOI: 10.1111/mmi.13413

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      Abbreviated Summary

      In Escherichia coli both poly(A) polymerase I (PAP I) and polynucleotide phosphorylase (PNPase) can add nucleotides to the 3' termini of a variety of RNA molecules (mRNAs, rRNAs, tRNAs and sRNAs). However, the addition of poly(A) tails by PAP I after Rho-independent transcription terminators, surprisingly, requires both an intact RNase E-based degradosome and a functional PNPase protein.

    2. Function, expression, specificity, diversity, and incompatibility of actinobacteriophage parABS systems

      Rebekah M. Dedrick, Travis N. Mavrich, Wei L. Ng, Juan C. Cervantes Reyes, Matthew R. Olm, Rachael E. Rush, Deborah Jacobs-Sera, Daniel A. Russell and Graham F. Hatfull

      Accepted manuscript online: 5 MAY 2016 03:45AM EST | DOI: 10.1111/mmi.13414

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      Over 40 completely sequenced temperate actinobacteriophages encode diverse Type Ib partitioning cassettes containing parA and parB genes as well as centromere-like sites parS-L and parS-R. Their prophages replicate extrachromosomally at low copy number and the partitioning systems mediate prophage maintenance, although related phages exhibit lysogenic incompatibility through competition of ParB binding to the parS sites.

    3. A protein complex supports the production of Spo0A-P and plays additional roles for biofilms and the K-state in Bacillus subtilis

      Eugenie J. Dubnau, Valerie J. Carabetta, Andrew W. Tanner, Mathieu Miras, Christine Diethmaier and David Dubnau

      Accepted manuscript online: 3 MAY 2016 05:56PM EST | DOI: 10.1111/mmi.13411

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      In Bacillus subtilis, the proteins YlbF, YmcA and YaaT form a complex needed for the formation of biofilms, for sporulation and for genetic transformation. This paper strongly supports a role for these proteins in stimulating the phosphorylation of the key transcription factor, Spo0A. The present data contradict an alternative published model that proposed a role for the complex in destabilizing the mRNA for SinR, a repressor of biofilm formation.

    4. L-fucose influences chemotaxis and biofilm formation in Campylobacter jejuni

      Ritika Dwivedi, Harald Nothaft, Jolene Garber, Lin Xin Kin, Martin Stahl, Annika Flint, Arnoud H. M. van Vliet, Alain Stintzi and Christine M. Szymanski

      Accepted manuscript online: 3 MAY 2016 09:46AM EST | DOI: 10.1111/mmi.13409

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      Abbreviated Summary

      The influence of fucose availability on C. jejuni chemotaxis and biofilm formation was investigated. Wildtype (WT) C. jejuni forms biofilms when nutrients are limited, but swims towards L-fucose (blue ovals) and exhibits enhanced growth and reduced biofilms in its presence. Disruption of fucose uptake through mutation of the permease, fucP, results in biofilm formation even though chemotaxis is not affected. The putative dehydrogenase mutant, cj0485, abolishes both phenotypes suggesting a key role in fucose chemotaxis.

    5. Base J represses genes at the end of polycistronic gene clusters in Leishmania major by promoting RNAP II termination

      David L. Reynolds, Brigitte T. Hofmeister, Laura Cliffe, T. Nicolai Siegel, Britta A. Anderson, Stephen M. Beverley, Robert J. Schmitz and Robert Sabatini

      Accepted manuscript online: 29 APR 2016 04:20AM EST | DOI: 10.1111/mmi.13408

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      Base J regulates gene expression by stimulating premature termination within gene clusters in Leishmania major. Loss of base J within gene clusters leads to read through transcription and upregulation of genes downstream of base J. The loss of base J at the end of gene clusters results in read through transcription into the opposing gene clusters. However, transcription of the opposing DNA strand has no effect on mRNA levels from the sense strand.

    6. A new piperidinol derivative targeting mycolic acid transport in Mycobacterium abscessus

      Christian Dupont, Albertus Viljoen, Faustine Dubar, Mickaël Blaise, Audrey Bernut, Alexandre Pawlik, Christiane Bouchier, Roland Brosch, Yann Guérardel, Joël Lelièvre, Lluis Ballell, Jean-Louis Herrmann, Christophe Biot and Laurent Kremer

      Accepted manuscript online: 28 APR 2016 04:35AM EST | DOI: 10.1111/mmi.13406

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      The piperidinol-based lead compound PIPD1 inhibits growth of Mycobacterium abscessus by targeting MAB_4508, an MmpL family member participating in the transport of trehalose monomycolate (TMM), leading to the loss of arabinogalactan mycolylation. Multiple mutations in MAB_4508 conferring high resistance levels to PIPD1 helped to define a potential PIPD1-binding pocket. Our findings emphasize a yet unexploited chemical structure class against M. abscessus infections with promising translational development possibilities.

    7. Evolved plasmid-host interactions reduce plasmid interference cost

      Hirokazu Yano, Katarznya Wegrzyn, Wesley Loftie-Eaton, Jenny Johnson, Gail E. Deckert, Linda M. Rogers, Igor Konieczny and Eva M. Top

      Accepted manuscript online: 28 APR 2016 04:30AM EST | DOI: 10.1111/mmi.13407

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      The molecular mechanisms by which a broad-host-range antibiotic resistance plasmid can adapt to a novel bacterial host and increase its persistence were investigated using experimentally evolved plasmids. These evolved plasmids encode a modified replication initiation protein that simultaneously increases plasmid copy number and decreases interference cost by decreasing binding affinity to the host helicase (DnaB). This in turn causes plasmid replication to be dependent on host DnaA, an example of host specialization.

    8. A Spectrum of CodY Activities Drives Metabolic Reorganization and Virulence Gene Expression in Staphylococcus aureus

      Nicholas R. Waters, David J. Samuels, Ranjan K. Behera, Jonathan Livny, Kyu Y. Rhee, Marat R. Sadykov and Shaun R. Brinsmade

      Accepted manuscript online: 26 APR 2016 10:10AM EST | DOI: 10.1111/mmi.13404

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      By analyzing transcriptome profiles and assessing in vitro phenotypes of S. aureus strains producing variants of CodY with variable activity, we shed light on an important link between metabolism and virulence. We show that nutrient acquisition and synthesis, as well as biofilm formation and nuclease production are under graded CodY control. We infer that CodY plays a crucial role in orchestrating responses to environmental nutrient stress, including responses that can be detrimental to the host.

    9. Cyclic-di-GMP Regulation of Bacillus cereus Group Biofilm Formation

      Annette Fagerlund, Veronika Smith, Åsmund K. Røhr, Toril Lindbäck, Marthe P. Parmer, K. Kristoffer Andersson, Leon Reubsaet and Ole Andreas Økstad

      Accepted manuscript online: 26 APR 2016 10:10AM EST | DOI: 10.1111/mmi.13405

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      By a genome-wide approach we show that the second messenger cyclic-di-GMP regulates biofilm formation, and also affects motility and cytotoxicity, in Bacillus thuringiensis 407. Furthermore, genes linked to c-di-GMP responses (cdg genes) were found to be ubiquitous in Bacillus cereus group bacteria, including the obligate human pathogen Bacillus anthracis. Only two of the cdg genes had orthologs in Bacillus subtilis, highlighting differences in c-di-GMP signalling between B. subtilis and B. cereus group bacteria.

    10. Concerted action of NIC relaxase and auxiliary protein MobC in RA3 plasmid conjugation

      Jolanta Godziszewska, Gabriel Moncalián, Matilde Cabezas, Aneta A. Bartosik, Fernando de la Cruz and Grazyna Jagura-Burdzy

      Accepted manuscript online: 21 APR 2016 07:05PM EST | DOI: 10.1111/mmi.13401

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      The mobC-nic operon of broad-host-range conjugative RA3 plasmid (IncU incompatibility group) encodes HUH relaxase NIC (MOBP4 subgroup) and a transcriptional regulator MobC. Here we delineated minimal oriTRA3, identified the NIC_RA3 binding site and its metal ions preference. The interplay between these two proteins was demonstrated: the MobC participates in the efficient NIC cleavage of supercoiled oriTRA3 and NIC_RA3 potentiates the MobC repression of the mobC promoter.

  7. MicroCommentary

    1. You have free access to this content
      Two ways to skin a cat: ADEP antibiotics can kill bacteria through activation or inhibition of ClpP activity

      Robert H. Vass and Peter Chien

      Accepted manuscript online: 22 MAR 2016 01:20AM EST | DOI: 10.1111/mmi.13382

  8. Research Articles

    1. PbsP, a cell wall-anchored protein that binds plasminogen to promote hematogenous dissemination of Group B Streptococcus

      Marco Buscetta, Arnaud Firon, Giampiero Pietrocola, Carmelo Biondo, Giuseppe Mancuso, Angelina Midiri, Letizia Romeo, Roberta Galbo, Mario Venza, Isabella Venza, Pierre-Alexandre Kaminski, Myriam Gominet, Giuseppe Teti, Pietro Speziale, Patrick Trieu-Cuot and Concetta Beninati

      Accepted manuscript online: 16 FEB 2016 05:15PM EST | DOI: 10.1111/mmi.13357

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      We describe here Plasminogen binding surface Protein, or PbsP, a highly conserved virulence factor of group B streptococci. This adhesin contains two Streptococcal Surface Repeat domains, a methionine- and lysine-rich region and an LPXTG cell-wall anchoring motif. PbsP largely mediates the ability of group B streptococcal strain NEM316 to bind plasminogen, acquire proteolytic activity and transmigrate through brain endothelial cells, resulting in meningoencephalitis. Moreover, immunization of mice with PbsP confers protective immunity.

    2. The immune evasion protein Sbi of Staphylococcus aureus occurs both extracellularly and anchored to the cell envelope by binding lipoteichoic acid

      Emma Jane Smith, Rebecca M. Corrigan, Tetje van der Sluis, Angelika Gründling, Pietro Speziale, Joan A. Geoghegan and Timothy J. Foster

      Accepted manuscript online: 10 JAN 2012 05:49AM EST | DOI: 10.1111/j.1365-2958.2012.07966.x


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