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https://www.readbyqxmd.com/read/29131301/genome-wide-identification-of-tolerance-mechanisms-towards-p-coumaric-acid-in-pseudomonas-putida
#1
Patricia Calero, Sheila I Jensen, Klara Bojanovič, Rebecca Lennen, Anna Koza, Alex T Nielsen
The soil bacterium Pseudomonas putida KT2440 has gained increasing biotechnological interest due to its ability to tolerate different types of stress. Here, the tolerance of P. putida KT2440 towards eleven toxic chemical compounds was investigated. P. putida was found to be significantly more tolerant towards three of the eleven compounds when compared to Escherichia coli. Increased tolerance was for example found towards p-coumaric acid, an interesting precursor for polymerization with a significant industrial relevance...
November 13, 2017: Biotechnology and Bioengineering
https://www.readbyqxmd.com/read/29109185/genome-wide-screens-reveal-new-gene-products-that-influence-genetic-competence-in-streptococcus-mutans
#2
Robert C Shields, Greg O'Brien, Natalie Maricic, Alexandria Kesterson, Megan Grace, Stephen J Hagen, Robert A Burne
A network of genes and at least two peptide signaling molecules tightly control when Streptococcus mutans becomes competent to take up DNA from its environment. Widespread changes in the expression of genes occur when S. mutans is presented with competence signal peptides in vitro, including increased production of the alternative sigma factor, ComX, which activates late competence genes. Still, the way that gene products that are regulated by competence peptides influence DNA uptake and cellular physiology are not well understood...
November 6, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/29109175/the-streptococcus-agalactiae-stringent-response-enhances-virulence-and-persistence-in-human-blood
#3
Thomas A Hooven, Andrew J Catomeris, Maryam Bonakdar, Luke J Tallon, Ivette Santana-Cruz, Sandra Ott, Sean C Daugherty, Hervé Tettelin, Adam J Ratner
Streptococcus agalactiae (group B Streptococcus, GBS) causes serious infection in neonates. We previously reported a Tn-seq system for performing genome-wide assessment of gene fitness in GBS. In order to identify molecular mechanisms required for GBS to transition from a mucosal commensal lifestyle to bloodstream invasion, we performed Tn-seq on GBS coincubated with human whole blood. Our analysis identified 16 genes conditionally essential for GBS survival in blood, of which 75% were members of the capsular polysaccharide (cps) operon...
November 6, 2017: Infection and Immunity
https://www.readbyqxmd.com/read/29099305/peripheral-blood-vessels-are-a-niche-for-blood-borne-meningococci
#4
Elena Capel, Jean-Philippe Barnier, Aldert L Zomer, Christine Bole-Feysot, Thomas Nussbaumer, Anne Jamet, Hervé Lécuyer, Daniel Euphrasie, Zoé Virion, Eric Frapy, Philippe Pélissier, Olivier Join-Lambert, Thomas Rattei, Sandrine Bourdoulous, Xavier Nassif, Mathieu Coureuil
Neisseria meningitidis is the causative agent of cerebrospinal meningitis and that of a rapidly progressing fatal septic shock known as purpura fulminans. Meningococcemia is characterized by bacterial adhesion to human endothelial cells of the microvessels. Host specificity has hampered studies on the role of blood vessels colonization in N. meningitidis associated pathogenesis. In this work, using a humanized model of SCID mice allowing the study of bacterial adhesion to human cells in an in vivo context we demonstrate that meningococcal colonization of human blood vessels is a prerequisite to the establishment of sepsis and lethality...
November 3, 2017: Virulence
https://www.readbyqxmd.com/read/29032547/genome-wide-mutagenesis-in-borrelia-burgdorferi
#5
Tao Lin, Lihui Gao
Signature-tagged mutagenesis (STM) is a functional genomics approach to identify bacterial virulence determinants and virulence factors by simultaneously screening multiple mutants in a single host animal, and has been utilized extensively for the study of bacterial pathogenesis, host-pathogen interactions, and spirochete and tick biology. The signature-tagged transposon mutagenesis has been developed to investigate virulence determinants and pathogenesis of Borrelia burgdorferi. Mutants in genes important in virulence are identified by negative selection in which the mutants fail to colonize or disseminate in the animal host and tick vector...
2018: Methods in Molecular Biology
https://www.readbyqxmd.com/read/28994778/creation-of-a-dense-transposon-insertion-library-using-bacterial-conjugation-in-enterobacterial-strains-such-as-escherichia-coli-or-shigella-flexneri
#6
Nikki E Freed
Transposon mutagenesis is a method that allows gene disruption via the random genomic insertion of a piece of DNA called a transposon. The protocol below outlines a method for high efficiency transfer between bacterial strains of a plasmid harboring a transposon containing a kanamycin resistance marker. The plasmid-borne transposase is encoded by a variant tnp gene that inserts the transposon into the genome of the recipient strain with very low insertional bias. This method thus allows the creation of large mutant libraries in which transposons have been inserted into unique genomic positions in a recipient strain of either Escherichia coli or Shigella flexneri bacteria...
September 23, 2017: Journal of Visualized Experiments: JoVE
https://www.readbyqxmd.com/read/28943871/global-screening-of-salmonella-enterica-serovar-typhimurium-genes-for-desiccation-survival
#7
Rabindra K Mandal, Young M Kwon
Salmonella spp., one of the most common foodborne bacterial pathogens, has the ability to survive under desiccation conditions in foods and food processing facilities for years. This raises the concerns of Salmonella infection in humans associated with low water activity foods. Salmonella responds to desiccation stress via complex pathways involving immediate physiological actions as well as coordinated genetic responses. However, the exact mechanisms of Salmonella to resist desiccation stress remain to be fully elucidated...
2017: Frontiers in Microbiology
https://www.readbyqxmd.com/read/28900609/genes-contributing-to-porphyromonas-gingivalis-fitness-in-abscess-and-epithelial-cell-colonization-environments
#8
Daniel P Miller, Justin A Hutcherson, Yan Wang, Zuzanna M Nowakowska, Jan Potempa, Deborah R Yoder-Himes, David A Scott, Marvin Whiteley, Richard J Lamont
Porphyromonas gingivalis is an important cause of serious periodontal diseases, and is emerging as a pathogen in several systemic conditions including some forms of cancer. Initial colonization by P. gingivalis involves interaction with gingival epithelial cells, and the organism can also access host tissues and spread haematogenously. To better understand the mechanisms underlying these properties, we utilized a highly saturated transposon insertion library of P. gingivalis, and assessed the fitness of mutants during epithelial cell colonization and survival in a murine abscess model by high-throughput sequencing (Tn-Seq)...
2017: Frontiers in Cellular and Infection Microbiology
https://www.readbyqxmd.com/read/28855313/complexity-of-complement-resistance-factors-expressed-by-acinetobacter-baumannii-needed-for-survival-in-human-serum
#9
Amaro F Sanchez-Larrayoz, Noha M Elhosseiny, Marc G Chevrette, Yang Fu, Peter Giunta, Raúl G Spallanzani, Keerthikka Ravi, Gerald B Pier, Stephen Lory, Tomás Maira-Litrán
Acinetobacter baumannii is a bacterial pathogen with increasing impact in healthcare settings, due in part to this organism's resistance to many antimicrobial agents, with pneumonia and bacteremia as the most common manifestations of disease. A significant proportion of clinically relevant A. baumannii strains are resistant to killing by normal human serum (NHS), an observation supported in this study by showing that 12 out of 15 genetically diverse strains of A. baumannii are resistant to NHS killing. To expand our understanding of the genetic basis of A...
October 15, 2017: Journal of Immunology: Official Journal of the American Association of Immunologists
https://www.readbyqxmd.com/read/28832676/genome-wide-discovery-of-novel-m1t1-group-a-streptococcal-determinants-important-for-fitness-and-virulence-during-soft-tissue-infection
#10
Yoann Le Breton, Ashton T Belew, Jeffrey A Freiberg, Ganesh S Sundar, Emrul Islam, Joshua Lieberman, Mark E Shirtliff, Hervé Tettelin, Najib M El-Sayed, Kevin S McIver
The Group A Streptococcus remains a significant human pathogen causing a wide array of disease ranging from self-limiting to life-threatening invasive infections. Epithelium (skin or throat) colonization with progression to the subepithelial tissues is the common step in all GAS infections. Here, we used transposon-sequencing (Tn-seq) to define the GAS 5448 genetic requirements for in vivo fitness in subepithelial tissue. A near-saturation transposon library of the M1T1 GAS 5448 strain was injected subcutaneously into mice, producing suppurative inflammation at 24 h that progressed to prominent abscesses with tissue necrosis at 48 h...
August 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28806924/essential-genome-of-campylobacter-jejuni
#11
Rabindra K Mandal, Tieshan Jiang, Young Min Kwon
BACKGROUND: Campylobacter species are a leading cause of bacterial foodborne illness worldwide. Despite the global efforts to curb them, Campylobacter infections have increased continuously in both developed and developing countries. The development of effective strategies to control the infection by this pathogen is warranted. The essential genes of bacteria are the most prominent targets for this purpose. In this study, we used transposon sequencing (Tn-seq) of a genome-saturating library of Tn5 insertion mutants to define the essential genome of C...
August 14, 2017: BMC Genomics
https://www.readbyqxmd.com/read/28765224/genome-wide-sensitivity-analysis-of-the-microsymbiont-sinorhizobium-meliloti-to-symbiotically-important-defensin-like-host-peptides
#12
Markus F F Arnold, Mohammed Shabab, Jon Penterman, Kevin L Boehme, Joel S Griffitts, Graham C Walker
The model legume species Medicago truncatula expresses more than 700 nodule-specific cysteine-rich (NCR) signaling peptides that mediate the differentiation of Sinorhizobium meliloti bacteria into nitrogen-fixing bacteroids. NCR peptides are essential for a successful symbiosis in legume plants of the inverted-repeat-lacking clade (IRLC) and show similarity to mammalian defensins. In addition to signaling functions, many NCR peptides exhibit antimicrobial activity in vitro and in vivo Bacterial resistance to these antimicrobial activities is likely to be important for symbiosis...
August 1, 2017: MBio
https://www.readbyqxmd.com/read/28760848/comprehensive-arrayed-transposon-mutant-library-of-klebsiella-pneumoniae-outbreak-strain-kpnih1
#13
Beth Ramage, Roxanne Erolin, Kiara Held, Joe Gasper, Eli Weiss, Mitch Brittnacher, Larry Gallagher, Colin Manoil
Klebsiella pneumoniae and other carbapenem-resistant Enterobacteriaceae are a major cause of hospital-acquired infections, yet the basis of their success as nosocomial pathogens is poorly understood. To help provide a foundation for genetic analysis of K. pneumoniae, we created an arrayed, sequence-defined transposon mutant library of an isolate from the 2011 outbreak of infections at the U.S. National Institutes of Health Clinical Center. The library is made up of 12,000 individually arrayed mutants of a carbapenemase deletion parent strain and provides coverage of 85% of predicted genes...
July 31, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28749938/the-mecillinam-resistome-reveals-a-role-for-peptidoglycan-endopeptidases-in-stimulating-cell-wall-synthesis-in-escherichia-coli
#14
Ghee Chuan Lai, Hongbaek Cho, Thomas G Bernhardt
Bacterial cells are typically surrounded by an net-like macromolecule called the cell wall constructed from the heteropolymer peptidoglycan (PG). Biogenesis of this matrix is the target of penicillin and related beta-lactams. These drugs inhibit the transpeptidase activity of PG synthases called penicillin-binding proteins (PBPs), preventing the crosslinking of nascent wall material into the existing network. The beta-lactam mecillinam specifically targets the PBP2 enzyme in the cell elongation machinery of Escherichia coli...
July 2017: PLoS Genetics
https://www.readbyqxmd.com/read/28683752/tnseqdiff-identification-of-conditionally-essential-genes-in-transposon-sequencing-studies
#15
Lili Zhao, Mark T Anderson, Weisheng Wu, Harry L T Mobley, Michael A Bachman
BACKGROUND: Tn-Seq is a high throughput technique for analysis of transposon mutant libraries to determine conditional essentiality of a gene under an experimental condition. A special feature of the Tn-seq data is that multiple mutants in a gene provides independent evidence to prioritize that gene as being essential. The existing methods do not account for this feature or rely on a high-density transposon library. Moreover, these methods are unable to accommodate complex designs. RESULTS: The method proposed here is specifically designed for the analysis of Tn-Seq data...
July 6, 2017: BMC Bioinformatics
https://www.readbyqxmd.com/read/28677146/genes-essential-for-phototrophic-growth-by-a-purple-alphaproteobacterium
#16
Jianming Yang, Liang Yin, Faith H Lessner, Ernesto S Nakayasu, Samuel H Payne, Kathryn R Fixen, Larry Gallagher, Caroline S Harwood
Tn-seq was used to identify genes essential for phototrophic growth by the purple bacterium Rhodopseudomonas palustris. About 167 genes required for anaerobic growth on acetate in light were identified, 35 of which are annotated as photosynthesis genes. The essentiality of many of these genes by analysing the phenotypes of independently generated mutants that had altered pigmentation was verified. Three genes were identified, two possibly involved in biogenesis of the membrane-bound photosynthetic apparatus and one for phosphatidylcholine biosynthesis, that were not known to be essential for phototrophic growth...
July 5, 2017: Environmental Microbiology
https://www.readbyqxmd.com/read/28674067/genome-scale-mutational-analysis-of-geobacter-sulfurreducens-reveals-distinct-molecular-mechanisms-for-respiration-and-sensing-of-poised-electrodes-versus-fe-iii-oxides
#17
Chi Ho Chan, Caleb E Levar, Fernanda Jiménez-Otero, Daniel R Bond
Geobacter sulfurreducens generates electrical current by coupling intracellular oxidation of organic acids to the reduction of proteins on the cell surface that are able to interface with electrodes. This ability is attributed to the bacterium's capacity to respire other extracellular electron acceptors that require contact, such as insoluble metal oxides. To directly investigate the genetic basis of electrode-based respiration, we constructed Geobacter sulfurreducens transposon-insertion sequencing (Tn-Seq) libraries for growth, with soluble fumarate or an electrode as the electron acceptor...
October 1, 2017: Journal of Bacteriology
https://www.readbyqxmd.com/read/28614382/genome-wide-transposon-mutagenesis-of-proteus-mirabilis-essential-genes-fitness-factors-for-catheter-associated-urinary-tract-infection-and-the-impact-of-polymicrobial-infection-on-fitness-requirements
#18
Chelsie E Armbruster, Valerie Forsyth-DeOrnellas, Alexandra O Johnson, Sara N Smith, Lili Zhao, Weisheng Wu, Harry L T Mobley
The Gram-negative bacterium Proteus mirabilis is a leading cause of catheter-associated urinary tract infections (CAUTIs), which are often polymicrobial. Numerous prior studies have uncovered virulence factors for P. mirabilis pathogenicity in a murine model of ascending UTI, but little is known concerning pathogenesis during CAUTI or polymicrobial infection. In this study, we utilized five pools of 10,000 transposon mutants each and transposon insertion-site sequencing (Tn-Seq) to identify the full arsenal of P...
June 2017: PLoS Pathogens
https://www.readbyqxmd.com/read/28498899/magenta-a-galaxy-implemented-tool-for-complete-tn-seq-analysis-and-data-visualization
#19
Katherine Maia McCoy, Margaret L Antonio, Tim van Opijnen
Motivation: Transposon insertion sequencing (Tn-Seq) is a microbial systems-level tool, that can determine on a genome-wide scale and in high-throughput, whether a gene, or a specific genomic region, is important for fitness under a specific experimental condition. Results: Here, we present MAGenTA, a suite of analysis tools which accurately calculate the growth rate for each disrupted gene in the genome to enable the discovery of: (i) new leads for gene function, (ii) non-coding RNAs; (iii) genes, pathways and ncRNAs that are involved in tolerating drugs or induce disease; (iv) higher order genome organization; and (v) host-factors that affect bacterial host susceptibility...
September 1, 2017: Bioinformatics
https://www.readbyqxmd.com/read/28490437/high-throughput-crispri-phenotyping-identifies-new-essential-genes-in-streptococcus-pneumoniae
#20
Xue Liu, Clement Gallay, Morten Kjos, Arnau Domenech, Jelle Slager, Sebastiaan P van Kessel, Kèvin Knoops, Robin A Sorg, Jing-Ren Zhang, Jan-Willem Veening
Genome-wide screens have discovered a large set of essential genes in the opportunistic human pathogen Streptococcus pneumoniae However, the functions of many essential genes are still unknown, hampering vaccine development and drug discovery. Based on results from transposon sequencing (Tn-seq), we refined the list of essential genes in S. pneumoniae serotype 2 strain D39. Next, we created a knockdown library targeting 348 potentially essential genes by CRISPR interference (CRISPRi) and show a growth phenotype for 254 of them (73%)...
May 10, 2017: Molecular Systems Biology
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