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Journal of Bacteriology

Anne-Marie Garnerone, Fernando Sorroche, Lan Zou, Céline Mathieu-Demazière, Chang Fu Tian, Catherine Masson-Boivin, Jacques Batut
An ongoing signal exchange fine-tunes the symbiotic interaction between rhizobia and legumes, ensuring the establishment and maintenance of mutualism. In a recently identified regulatory loop, endosymbiotic S. meliloti exert a negative feedback on root infection in response to unknown plant cues. Upon signal perception, three bacterial Adenylate Cyclases (ACs) of the inner membrane, CyaD1, CyaD2 and CyaK, synthesize the second messenger cAMP that, together with the cAMP-dependent Clr transcriptional activator, activates the expression of genes involved in root infection control...
March 12, 2018: Journal of Bacteriology
Joanna Hołówka, Damian Trojanowski, Mateusz Janczak, Dagmara Jakimowicz, Jolanta Zakrzewska-Czerwińska
The bacterial chromosome undergoes dynamic changes in response to ongoing cellular processes and adaptation to environmental conditions. Among the many proteins involved in maintaining this dynamism, the most abundant is the nucleoid-associated protein (NAP), HU. In mycobacteria, the HU homolog, HupB, possesses an additional C-terminal domain that resembles that of eukaryotic histones H1/H5. Recently, we demonstrated that the highly abundant HupB occupies the entirety of the M. smegmatis chromosome and exhibits a bias from the origin ( oriC ) to the terminus ( ter )...
March 12, 2018: Journal of Bacteriology
Simon Ringgaard, Wen Yang, Alejandra Alvarado, Kathrin Schirner, Ariane Briegel
Most motile bacteria are able to bias their movement towards more favorable environments or to escape from obnoxious substances by a process called chemotaxis. Chemotaxis depends on a chemosensory system that is able to sense specific environmental signals and generate a behavioral response. Typically, the signal is transmitted to the bacterial flagellum, ultimately regulating the swimming behavior of individual cells. Chemotaxis is mediated by proteins that assemble into large, highly ordered arrays. It is imperative for successful chemotactic behavior and cellular competitiveness that chemosensory arrays form and localize properly within the cell...
March 12, 2018: Journal of Bacteriology
Jyl S Matson
In this issue of the Journal of Bacteriology , Hustmyer and colleagues describe a new method for rapidly generating reporter libraries (Hustmyer citation). This RAIL technique (<u>R</u>apid<u>A</u>rbitrary PCR<u>I</u>nsertion<u>L</u>ibraries) uses arbitrary PCR and isothermal DNA assembly to insert random fragments of promoter regions into reporter plasmids, resulting in libraries that can be screened to identify regions required for gene expression. This technique will likely be useful for a number of different genetic applications...
March 12, 2018: Journal of Bacteriology
Christine M Hustmyer, Chelsea A Simpson, Stephen G Olney, Matthew L Bochman, Julia C van Kessel
Experimental studies of transcriptional regulation in bacteria require the ability to precisely measure changes in gene expression, often accomplished through the use of reporter genes. However, the boundaries of promoter sequences required for transcription are often unknown, thus complicating construction of reporters and genetic analysis of transcriptional regulation. Here, we analyze reporter libraries to define the promoter boundaries of the luxCDABE bioluminescence operon and the betIBA-proXWV osmotic stress operon in Vibrio harveyi We describe a new method called RAIL (<u>R</u>apid<u>A</u>rbitrary PCR<u>I</u>nsertion<u>L</u>ibraries) that combines the power of arbitrary PCR and isothermal DNA assembly to rapidly clone promoter fragments of various lengths upstream of reporter genes to generate large libraries...
March 12, 2018: Journal of Bacteriology
Mohammad Dadashipour, Mariko Iwamoto, Md Murad Hossain, Jun-Ichi Akutsu, Zilian Zhang, Yutaka Kawarabayasi
Most organisms, from Bacteria to Eukarya, synthesize UDP- N -acetylglucosamine (UDP-GlcNAc) from fructose-6-phosphate via a four-step reaction, and UDP- N -acetylgalactosamine (UDP-GalNAc) can only be synthesized from UDP-GlcNAc by UDP-GlcNAc 4-epimerase. In Archaea, the bacterial-type UDP-GlcNAc biosynthetic pathway was reported for Methanococcales. However, the complete biosynthetic pathways for UDP-GlcNAc and UDP-GalNAc present in one Archaeal species are unidentified. Previous experimental analyses on enzymatic activities of the ST0452 protein, identified from the thermophilic Crenarchaeon Sulfolobus tokodaii , predicted the presence of both a bacterial-type UDP-GlcNAc and an independent UDP-GalNAc biosynthetic pathway in this Archaeon...
March 5, 2018: Journal of Bacteriology
Eric D Peng, Diana M Oram, Marcos D Battistel, Lindsey R Lyman, Darón I Freedberg, Michael P Schmitt
Corynebacterium diphtheriae , a Gram-positive, aerobic bacterium, is the causative agent of diphtheria and cutaneous infections. While mechanisms required for heme iron acquisition are well known in C. diphtheriae , systems involved in the acquisition of other metals such as zinc and manganese remain poorly characterized. In this study, we identified a genetic region that encodes an ABC-type transporter ( iutBCD ) flanked by two genes ( iutA and iutE ) encoding putative substrate binding proteins of the cluster 9 family, a related group of transporters primarily associated with the import of Mn and Zn...
March 5, 2018: Journal of Bacteriology
Hannah A Bullock, Huifeng Shen, Tye O Boynton, Lawrence J Shimkets
Myxococcus xanthus cells produce lipid bodies containing triacylglycerides during fruiting body development. Fatty acid β-oxidation is the most energy efficient pathway for lipid body catabolism. In this study, we used mutants in fadJ (MXAN_5371 and MXAN_6987) and fadI (MXAN_5372) homologs to examine whether β-oxidation serves an essential developmental function. These mutants contained more lipid bodies than wild type strain DK1622 and 2-fold more FAD consistent with reduced consumption of fatty acids by β-oxidation...
March 5, 2018: Journal of Bacteriology
Louise Djapgne, Subrata Panja, Luke Brewer, Jonathan Gans, Maureen A Kane, Sarah A Woodson, Amanda G Oglesby-Sherrouse
Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that requires iron for growth and virulence. In low iron conditions, P. aeruginosa transcribes two highly identical (95%) small regulatory RNAs (sRNAs), PrrF1 and PrrF2, which are required for virulence in acute murine lung infection models. The PrrF sRNAs promote the production of 2-akly-4(1 H )-quinolone metabolites (AQs) that mediate a range of biological activities, including quorum sensing and polymicrobial interactions. Here we show that the PrrF1 and PrrF2 sRNAs promote AQ production by redundantly inhibiting translation of antR , which encodes a transcriptional activator of the anthranilate degradation genes...
March 5, 2018: Journal of Bacteriology
Servane Le Guillouzer, Marie-Christine Groleau, Eric Déziel
The bacterium Burkholderia thailandensis possesses three N -acyl-L -homoserine lactone (AHL) quorum sensing (QS) systems designated BtaI1/BtaR1 (QS-1), BtaI2/BtaR2 (QS-2), and BtaI3/BtaR3 (QS-3). These QS systems are associated with the biosynthesis of N -octanoyl-homoserine lactone (C8 -HSL), N -3-hydroxy-decanoyl-homoserine lactone (3OHC10 -HSL), and N -3-hydroxy-octanoyl-homoserine lactone (3OHC8 -HSL), which are produced by the LuxI-type synthases BtaI1, BtaI2, and BtaI3, and modulated by the LuxR-type transcriptional regulators BtaR1, BtaR2, and BtaR3...
March 5, 2018: Journal of Bacteriology
Taylor I Herring, Tiffany N Harris, Chiranjit Chowdhury, Sujit Mohanty, Thomas A Bobik
Bacterial choline degradation in the human gut has been associated with cancer and heart disease. In addition, recent studies found that a bacterial microcompartment is involved in choline utilization by Proteus and Desulfovibrio However, many aspects of this process have not been fully defined. Here, we investigate choline degradation by the uropathogen Escherichia coli 536. Growth studies indicated E. coli 536 degrades choline primarily by fermentation. Electron microscopy indicated that a bacterial microcompartment was used for this process...
March 5, 2018: Journal of Bacteriology
Tiffany M Zarrella, Dennis W Metzger, Guangchun Bai
Cyclic di-adenosine monophosphate (c-di-AMP) is a newly discovered bacterial second messenger. However, regulation of c-di-AMP homeostasis is poorly understood. In Streptococcus pneumoniae , a sole diadenylate cyclase, CdaA, produces c-di-AMP and two phosphodiesterases, Pde1 and Pde2, cleave the signaling di-nucleotide. To expand our knowledge of the pneumococcal c-di-AMP signaling network, we performed whole genome sequencing of Δ pde1 Δ pde2 heat shock suppressors. In addition to surviving heat shock, these suppressor mutants restored general stress resistance and improved growth in rich medium...
February 26, 2018: Journal of Bacteriology
Patricia A Champion, Joshua D Shrout
The 24th Annual Midwest Microbial Pathogenesis Conference (MMPC) was held at the University of Notre Dame from August 25-27, 2017. The conference provided an opportunity for scientists from the Midwest to discuss new advances in microbial pathogenesis, including how pathogens promote disease, and how they interact with each other, the microbiome and the host. This commentary highlights the MMPC history, the topics presented at the conference and the reports in this issue.
February 26, 2018: Journal of Bacteriology
Saroj Poudel, Daniel R Colman, Kathryn R Fixen, Rhesa N Ledbetter, Yanning Zheng, Natasha Pence, Lance C Seefeldt, John W Peters, Caroline S Harwood, Eric S Boyd
Nitrogenase catalyzes the reduction of dinitrogen (N2 ) using low potential electrons from ferredoxin (Fd) or flavodoxin (Fld) through an ATP dependent process. Since its emergence in an anaerobic chemoautotroph, this oxygen (O2 ) sensitive enzyme complex has evolved to operate in a variety of genomic and metabolic backgrounds including those of aerobes, anaerobes, chemotrophs, and phototrophs. However, whether pathways of electron delivery to nitrogenase are influenced by these different metabolic backgrounds is not well understood...
February 26, 2018: Journal of Bacteriology
Tiffany A Claeys, Richard T Robinson
Nontuberculous mycobacteria (NTM) include species that colonize human epithelia, as well as species that are ubiquitous in soil and aquatic environments. NTM that primarily inhabit soil and aquatic environments include the Mycobacterium avium complex (MAC, M. avium and Mycobacterium intracellulare ) and the Mycobacterium abscessus complex (MABSC, M. abscessus subspecies abscessus , massiliense , and bolletii ), and can be free-living, biofilm-associated, or amoeba-associated. Although NTM are rarely pathogenic in immunocompetent individuals, those who are immunocompromised - due to either an inherited or acquired immunodeficiency - are highly susceptible to NTM infection (NTMI)...
February 26, 2018: Journal of Bacteriology
Julie Liao, Daniel R Smith, Jóhanna Brynjarsdóttir, Paula I Watnick
Diarrhea is the most common infection in children under the age of five worldwide. In spite of this, only a few vaccines to treat infectious diarrhea exist, and many of the available vaccines are sparingly and sporadically administered. Major obstacles to the development and widespread implementation of vaccination include the ease and cost of production, distribution, and delivery. Here we present a novel, customizable and self-assembling vaccine platform that exploits the Vibrio cholerae bacterial biofilm matrix for antigen presentation...
February 26, 2018: Journal of Bacteriology
Kyle C Costa, Leon S Moskatel, Lucas A Meirelles, Dianne K Newman
Phenazines are a class of bacterially-produced redox-active metabolites that are found in natural, industrial, and clinical environments. In Pseudomonas spp., phenazine-1-carboxylic acid (PCA)--the precursor of all phenazine metabolites--facilitates nutrient acquisition, biofilm formation, and competition with other organisms. While the removal of phenazines negatively impacts these activities, little is known about the genes or enzymes responsible for phenazine degradation by other organisms. Here, we report that the first step of PCA degradation by Mycobacterium fortuitum is catalyzed by a [underln]ph[/underln]enazine [underln]d[/underln]egrading decarboxylase (PhdA)...
February 26, 2018: Journal of Bacteriology
Xueye Ding, Qiang He, Fenglin Shen, Frederick W Dahlquist, Xiqing Wang
The histidine kinase CheA plays a central role in signal integration, conversion, and amplification in the bacterial chemotaxis signal transduction pathway. The kinase activity is regulated in chemotaxis signaling complexes formed via the interactions among CheA's regulatory domain (P5), the coupling protein CheW, and transmembrane chemoreceptors. Despite recent advancement in understanding of the architecture of the signaling complex, the molecular mechanism underlying this regulation remains elusive. An interdomain linker that connects the catalytic (P4) and regulatory domains of CheA may mediate regulatory signals from the P5/CheW/receptor interactions to the catalytic domain...
February 26, 2018: Journal of Bacteriology
Kayley H Janssen, Manisha R Diaz, Matthew Golden, Justin W Graham, Wes Sanders, Matthew C Wolfgang, Timothy L Yahr
Pseudomonas aeruginosa is a Gram-negative opportunistic pathogen with distinct acute and chronic virulence phenotypes. Whereas acute virulence is typically associated with expression of a type III secretion system (T3SS), chronic virulence is characterized by biofilm formation. Many of the phenotypes associated with acute and chronic virulence are inversely regulated by RsmA and RsmF. RsmA and RsmF are both members of the CsrA family of RNA-binding proteins and regulate protein synthesis at the post-transcriptional level...
February 20, 2018: Journal of Bacteriology
Yu-Cheng Lin, Matthew D Sekedat, William Cole Cornell, Gustavo M Silva, Chinweike Okegbe, Alexa Price-Whelan, Christine Vogel, Lars E P Dietrich
Microbes in biofilms face the challenge of substrate limitation. In particular, cells in Pseudomonas aeruginosa biofilms growing in the laboratory or during host colonization often become limited for oxygen. Previously we found that phenazines, antibiotics produced by P. aeruginosa , balance the intracellular redox state for cells in biofilms. Here, we show that genes involved in denitrification are induced in phenazine-null (Δ phz ) mutant biofilms grown under an aerobic atmosphere, even in the absence of nitrate...
February 20, 2018: Journal of Bacteriology
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