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858 results on '"Loessner, Martin J."'

202. Whole genome sequencing and comparative genomic analyses of two Vibrio cholerae O139 Bengal-specific Podovirusesto other N4-like phages reveal extensive genetic diversity

Author

Fouts, Derrick E, primary, Klumpp, Jochen, additional, Bishop-Lilly, Kimberly A, additional, Rajavel, Mathumathi, additional, Willner, Kristin M, additional, Butani, Amy, additional, Henry, Matthew, additional, Biswas, Biswajit, additional, Li, Manrong, additional, Albert, M John, additional, Loessner, Martin J, additional, Calendar, Richard, additional, and Sozhamannan, Shanmuga, additional

Published
2013
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203. Smoking Cessation Induces Profound Changes in the Composition of the Intestinal Microbiota in Humans

Author

Biedermann, Luc, primary, Zeitz, Jonas, additional, Mwinyi, Jessica, additional, Sutter-Minder, Eveline, additional, Rehman, Ateequr, additional, Ott, Stephan J., additional, Steurer-Stey, Claudia, additional, Frei, Anja, additional, Frei, Pascal, additional, Scharl, Michael, additional, Loessner, Martin J., additional, Vavricka, Stephan R., additional, Fried, Michael, additional, Schreiber, Stefan, additional, Schuppler, Markus, additional, and Rogler, Gerhard, additional

Published
2013
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204. Comparative genomics of Listeria bacteriophages

Author

Scherer, Siegfried (Prof. Dr.), Loessner, Martin J. (Prof. Dr.), Dorscht, Julia, Scherer, Siegfried (Prof. Dr.), Loessner, Martin J. (Prof. Dr.), and Dorscht, Julia

Abstract

The dsDNA of Listeria bacteriophages A006, A500, A511, B025, B054, and P35 were sequenced and analysed regarding G+C content, open reading frames, tRNA genes and sequence identities on nucleotide and protein level. Additionally, bacterial integration sites for the temperate phages were identified. Genes are arranged into functional, life-cycle specific modules. The mosaic nature of the genomes supports the modular evolution theory and provides insight into the phylogenetic relationship among the Listeria phages. Analysis of the structural proteins via peptide mass fingerprinting allowed a correlation between predicted gene products and protein bands from the profiles (SDS-Page) and indicated translational frameshifts during synthesis of the major capsid and major tail proteins in some phages., Die dsDNA-Genome der Listeria-Bakteriophagen A006, A500, A511, B025, B054 und P35 wurden sequenziert und hinsichtlich ihres G+C Gehalts, Offener Leseraster und tRNA-Genen, sowie Ähnlichkeiten auf Protein- und Nukleotidebene analysiert. Für die temperenten Phagen wurde zudem die Integrationsstelle im Wirtsgenom bestimmt. Es zeigte sich eine Anordnung der Gene in funktionellen Clustern, die bei temperenten Phagen den verschiedenen Stadien des Vermehrungszyklus entsprechen. Mosaikartig verteilte Ähnlichkeiten der Genome unterstützen die Theorie der modularen Phagenevolution und geben Einblick in die phylogentische Verwandtschaft der Listeria-Phagen. Über die Analyse der Strukturproteine mittels Massenspektrometrie gelang die Zuordnung bioinformatisch vorhergesagter Peptide zu Banden der Proteinprofile (SDS-Page). Zudem lieferte sie weitere Hinweise auf translationale Leserasterverschiebung bei der Synthese des Hauptkapsid- sowie Schwanzproteins einiger Phagen.

Published
2007

205. Magnetically Driven Silver-Coated Nanocoils for Efficient Bacterial Contact Killing.

Author

Hoop, Marcus, Shen, Yang, Chen, Xiang‐Zhong, Mushtaq, Fajer, Iuliano, Loredana M., Sakar, Mahmut S., Petruska, Andrew, Loessner, Martin J., Nelson, Bradley J., and Pané, Salvador

Subjects
MULTIDRUG resistance in bacteria, ANTIBIOTICS, DRUG therapy, ESCHERICHIA coli, SCANNING electron microscopes
Abstract

The increasing threat of multidrug-resistant bacterial strains against conventional antibiotic therapies represents a significant worldwide health risk and intensifies the need for novel antibacterial treatments. In this work, an effective strategy to target and kill bacteria using silver-coated magnetic nanocoils is reported. The coil palladium (Pd) nanostructures are obtained by electrodeposition and selective dealloying, and subsequently coated with nickel (Ni) and silver (Ag) for magnetic manipulation and antibacterial properties, respectively. The efficiency of the nanocoils is tested in the treatment of Gram-negative Escherichia coli ( E. coli) and Gram-positive methicillin-resistant Staphylococcus aureus ( S. aureus), both of which represent the leading multidrug-resistant bacterial pathogens. The nanocoils show highly effective bacterial killing activity at low concentrations and in relatively short durations of treatment time. Three different investigation techniques, LIVE/DEAD assay, colony-forming unit counting, and scanning electron microscope, reveal that the antibacterial activity is a result of bacterial membrane damage caused by direct contact with the nanocoil. The low cytotoxicity toward fibroblast cells along with the capability of precise magnetic locomotion makes the proposed nanocoil an ideal candidate to combat multidrug-resistant bacteria in the field of biomedical and environmental applications. [ABSTRACT FROM AUTHOR]

Published
2016
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209. Protein Tyrosine Phosphatase Nonreceptor Type 2 Regulates Autophagosome Formation in Human Intestinal Cells

Author

Scharl, Michael, primary, Wojtal, Kacper A., additional, Becker, Helen M., additional, Fischbeck, Anne, additional, Frei, Pascal, additional, Arikkat, Joba, additional, Pesch, Theresa, additional, Kellermeier, Silvia, additional, Boone, David L., additional, Weber, Achim, additional, Loessner, Martin J., additional, Vavricka, Stephan R., additional, Fried, Michael, additional, McCole, Declan F., additional, and Rogler, Gerhard, additional

Published
2012
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219. The Crohn's Disease Associated Variant of the Protein Tyrosine Phosphatase Non-Receptor Type 2 Gene Affects Cellular Responses to Invading Listeria Monocytogenes

Author

Scharl, Michael, primary, Wojtal, Kacper A., additional, Becker, Helen M., additional, Fischbeck, Anne, additional, Arikkat, Joba M., additional, Pesch, Theresa, additional, Kellermeier, Silvia, additional, Weber, Achim, additional, Loessner, Martin J., additional, Frei, Pascal, additional, Vavricka, Stephan R., additional, Fried, Michael, additional, McCole, Declan F., additional, and Rogler, Gerhard, additional

Published
2011
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224. Evaluation of Paramagnetic Beads Coated with RecombinantListeriaPhage Endolysin–Derived Cell-Wall-Binding Domain Proteins for Separation ofListeria monocytogenesfrom Raw Milk in Combination with Culture-Based and Real-Time Polymerase Chain Reaction–Based Quantification

Author

Walcher, Georg, primary, Stessl, Beatrix, additional, Wagner, Martin, additional, Eichenseher, Fritz, additional, Loessner, Martin J., additional, and Hein, Ingeborg, additional

Published
2010
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237. Pathogenomics of Listeria spp.

Author

Hain, Torsten, primary, Chatterjee, Som S., additional, Ghai, Rohit, additional, Kuenne, Carsten Tobias, additional, Billion, André, additional, Steinweg, Christiane, additional, Domann, Eugen, additional, Kärst, Uwe, additional, Jänsch, Lothar, additional, Wehland, Jürgen, additional, Eisenreich, Wolfgang, additional, Bacher, Adelbert, additional, Joseph, Biju, additional, Schär, Jennifer, additional, Kreft, Jürgen, additional, Klumpp, Jochen, additional, Loessner, Martin J., additional, Dorscht, Julia, additional, Neuhaus, Klaus, additional, Fuchs, Thilo M., additional, Scherer, Siegfried, additional, Doumith, Michel, additional, Jacquet, Christine, additional, Martin, Paul, additional, Cossart, Pascale, additional, Rusniock, Christophe, additional, Glaser, Philippe, additional, Buchrieser, Carmen, additional, Goebel, Werner, additional, and Chakraborty, Trinad, additional

Published
2007
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240. Putative type 1 thymidylate synthase and dihydrofolate reductase as signature genes of a novel bastille-like group of phages in the subfamily Spounavirinae.

Author

Tetteh Asare, Paul, Tae-Yong Jeong, Sangryeol Ryu, Klumpp, Jochen, Loessner, Martin J., Merrill, Bryan D., and Kwang-Pyo Kim

Subjects
MYOVIRIDAE, THYMIDYLATE synthase, METHYLTRANSFERASES, TETRAHYDROFOLATE dehydrogenase
Abstract

Background: Spounavirinae viruses have received an increasing interest as tools for the control of harmful bacteria due to their relatively broad host range and strictly virulent phenotype. Results: In this study, we collected and analyzed the complete genome sequences of 61 published phages, either ICTV-classified or candidate members of the Spounavirinae subfamily of the Myoviridae. A set of comparative analyses identified a distinct, recently proposed Bastille-like phage group within the Spounavirinae. More importantly, type 1 thymidylate synthase (TS1) and dihydrofolate reductase (DHFR) genes were shown to be unique for the members of the proposed Bastille-like phage group, and are suitable as molecular markers. We also show that the members of this group encode beta-lactamase and/or sporulation-related SpoIIIE homologs, possibly questioning their suitability as biocontrol agents. Conclusions: We confirm the creation of a new genus—the "Bastille-like group"—in Spounavirinae, and propose that the presence of TS1- and DHFR-encoding genes could serve as signatures for the new Bastille-like group. In addition, the presence of metallo-beta-lactamase and/or SpoIIIE homologs in all members of Bastille-like group phages makes questionable their suitability for use in biocontrol. [ABSTRACT FROM AUTHOR]

Published
2015
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241. Bacteriophage predation promotes serovar diversification in L isteria monocytogenes.

Author

Eugster, Marcel R., Morax, Laurent S., Hüls, Vanessa J., Huwiler, Simona G., Leclercq, Alexandre, Lecuit, Marc, and Loessner, Martin J.

Subjects
LISTERIA monocytogenes, BACTERIOPHAGE genetics, GENETIC mutation, PREDATION, GLYCOSYLATION, SEROTYPING
Abstract

L isteria monocytogenes is a bacterial pathogen classified into distinct serovars ( SVs) based on somatic and flagellar antigens. To correlate phenotype with genetic variation, we analyzed the wall teichoic acid ( WTA) glycosylation genes of SV 1/2, 3 and 7 strains, which differ in decoration of the ribitol-phosphate backbone with N-acetylglucosamine ( GlcNAc) and/or rhamnose. Inactivation of lmo1080 or the dTDP- l-rhamnose biosynthesis genes rml ACBD ( lmo1081-1084) resulted in loss of rhamnose, whereas disruption of lmo1079 led to GlcNAc deficiency. We found that all SV 3 and 7 strains actually originate from a SV 1/2 background, as a result of small mutations in WTA rhamnosylation and/or Glc NAcylation genes. Genetic complementation of different SV 3 and 7 isolates using intact alleles fully restored a characteristic SV 1/2 WTA carbohydrate pattern, including antisera reactions and phage adsorption. Intriguingly, phage-resistant L . monocytogenes EGDe ( SV 1/2a) isolates featured the same glycosylation gene mutations and were serotyped as SV 3 or 7 respectively. Again, genetic complementation restored both carbohydrate antigens and phage susceptibility. Taken together, our data demonstrate that L . monocytogenes SV 3 and 7 originate from point mutations in glycosylation genes, and we show that phage predation represents a major driving force for serovar diversification and evolution of L . monocytogenes. [ABSTRACT FROM AUTHOR]

Published
2015
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242. Evolutionarily distinct bacteriophage endolysins featuring conserved peptidoglycan cleavage sites protect mice from MRSA infection.

Author

Schmelcher, Mathias, Yang Shen, Nelson, Daniel C., Eugster, Marcel R., Eichenseher, Fritz, Hanke, Daniela C., Loessner, Martin J., Shengli Dong, Pritchard, David G., Lee, Jean C., Becker, Stephen C., Foster-Frey, Juli, and Donovan, David M.

Subjects
BACTERICIDAL action, PEPTIDOGLYCAN hydrolase, STAPHYLOCOCCUS aureus, METHICILLIN-resistant staphylococcus aureus, BIOFILMS, LABORATORY mice
Abstract

Objectives: In the light of increasing drug resistance in Staphylococcus aureus, bacteriophage endolysins [peptidoglycan hydrolases (PGHs)] have been suggested as promising antimicrobial agents. The aim of this study was to determine the antimicrobial activity of nine enzymes representing unique homology groups within a diverse class of staphylococcal PGHs. Methods: PGHs were recombinantly expressed, purified and tested for staphylolytic activity in multiple in vitro assays (zymogram, turbidity reduction assay and plate lysis) and against a comprehensive set of strains (S. aureus and CoNS). PGH cut sites in the staphylococcal peptidoglycan were determined by biochemical assays (Park- Johnson and Ghuysen procedures) and MS analysis. The enzymes were tested for their ability to eradicate static S. aureus biofilms and compared for their efficacy against systemic MRSA infection in a mouse model. Results: Despite similar modular architectures and unexpectedly conserved cleavage sites in the peptidoglycan (conferred by evolutionarily divergent catalytic domains), the enzymes displayed varying degrees of in vitro lytic activity against numerous staphylococcal strains, including cell surface mutants and drug-resistant strains, and proved effective against static biofilms. In a mouse model of systemic MRSA infection, six PGHs provided 100% protection from death, with animals being free of clinical signs at the end of the experiment. Conclusions: Our results corroborate the high potential of PGHs for treatment of S. aureus infections and reveal unique antimicrobial and biochemical properties of the different enzymes, suggesting a high diversity of potential applications despite highly conserved peptidoglycan target sites. [ABSTRACT FROM AUTHOR]

Published
2015
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243. Metabolite profiling and peptidoglycan analysis of transient cell wall-deficient bacteria in a new E scherichia coli model system.

Author

Cambré, Alexander, Zimmermann, Michael, Sauer, Uwe, Vivijs, Bram, Cenens, William, Michiels, Chris W., Aertsen, Abram, Loessner, Martin J., Noben, Jean ‐ Paul, Ayala, Juan A., Lavigne, Rob, and Briers, Yves

Subjects
PEPTIDOGLYCANS, BACTERIAL cell walls, ESCHERICHIA coli, BETA lactam antibiotics, CYTOLOGY, CELL membranes
Abstract

Many bacteria are able to assume a transient cell wall-deficient (or L-form) state under favourable osmotic conditions. Cell wall stress such as exposure to β-lactam antibiotics can enforce the transition to and maintenance of this state. L-forms actively proliferate and can return to the walled state upon removal of the inducing agent. We have adopted E scherichia coli as a model system for the controlled transition to and reversion from the L-form state, and have studied these dynamics with genetics, cell biology and 'omics' technologies. As such, a transposon mutagenesis screen underscored the requirement for the Rcs phosphorelay and colanic acid synthesis, while proteomics show only little differences between rods and L-forms. In contrast, metabolome comparison reveals the high abundance of lysophospholipids and phospholipids with unsaturated or cyclopropanized fatty acids in E . coli L-forms. This increase of membrane lipids associated with increased membrane fluidity may facilitate proliferation through bud formation. Visualization of the residual peptidoglycan with a fluorescently labelled peptidoglycan binding protein indicates de novo cell wall synthesis and a role for septal peptidoglycan synthesis during bud constriction. The DD-carboxypeptidases PBP5 and PBP6 are threefold and fourfold upregulated in L-forms, indicating a specific role for regulation of crosslinking during L-form proliferation. [ABSTRACT FROM AUTHOR]

Published
2015
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