Blar i forfatter "Harms, Klaus"

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    • Antimicrobial resistance acquisition via natural transformation: context is everything 

      Winter, Macaulay; Buckling, Angus; Harms, Klaus; Johnsen, Pål Jarle; Vos, Michiel (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-10-26)
      Natural transformation is a process where bacterial cells actively take up free DNA from the environment and recombine it into their genome or reconvert it into extra-chromosomal genetic elements. Although this mechanism is known to mediate the uptake of antibiotic resistance determinants in a range of human pathogens, its importance in the spread of antimicrobial resistance is not always appreciated. ...

    • Bacterial evolution on demand 

      Johnsen, Pål Jarle; Gama, João Alves; Harms, Klaus (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-06)
      Bacteria carry antibiotic resistant genes on movable sections of DNA that allow them to select the relevant genes on demand.

    • Costs and benefits of natural transformation in Acinetobacter baylyi 

      Hülter, Nils Fredrik; Sørum, Vidar; Borch-Pedersen, Kristina; Liljegren, Mikkel Meyn; Utnes, Ane; Primicerio, Raul; Harms, Klaus; Johnsen, Pål Jarle (Journal article; Tidsskriftartikkel; Peer reviewed, 2017-02-15)
      Background <br> Natural transformation enables acquisition of adaptive traits and drives genome evolution in prokaryotes. Yet, the selective forces responsible for the evolution and maintenance of natural transformation remain elusive since taken-up DNA has also been hypothesized to provide benefits such as nutrients or templates for DNA repair to individual cells. <br> Results <br> We investigated ...

    • Cryptic β-Lactamase Evolution Is Driven by Low β-Lactam Concentrations 

      Fröhlich, Christopher; Gama, João Alves; Harms, Klaus; Hirvonen, Viivi H. A.; Lund, Bjarte Aarmo; van der Kamp, Marc W.; Johnsen, Pål Jarle; Samuelsen, Ørjan; Leiros, Hanna-Kirsti S. (Journal article; Tidsskriftartikkel; Peer reviewed, 2021-04-28)
      Our current understanding of how low antibiotic concentrations shape the evolution of contemporary β-lactamases is limited. Using the widespread carbapenemase OXA-48, we tested the long-standing hypothesis that selective compartments with low antibiotic concentrations cause standing genetic diversity that could act as a gateway to developing clinical resistance. Here, we subjected <i>Escherichia ...

    • Evolutionary Instability of Collateral Susceptibility Networks in Ciprofloxacin-Resistant Clinical Escherichia coli Strains 

      Sørum, Vidar; Øynes, Emma Lu; Sollied Møller, Anna; Harms, Klaus; Samuelsen, Ørjan; Podnecky, Nicole L.; Johnsen, Pål Jarle (Journal article; Tidsskriftartikkel; Peer reviewed, 2022-07-07)
      ABSTRACT Collateral sensitivity and resistance occur when resistance development toward one antimicrobial either potentiates or deteriorates the effect of others. Previous reports on collateral effects on susceptibility focus on newly acquired resistance determinants and propose that novel treatment guidelines informed by collateral networks may reduce the evolution, selection, and spread of ...

    • Gene transfer potential of outer membrane vesicles of Acinetobacter baylyi and effects of stress on vesiculation 

      Fulsundar, Shweta; Harms, Klaus; Flaten, Gøril Eide; Johnsen, Pål Jarle; Chopade, Balu Ananda; Nielsen, Kaare Magne (Journal article; Tidsskriftartikkel; Peer reviewed, 2014)

    • Natural Transformation Facilitates Transfer of Transposons, Integrons and Gene Cassettes between Bacterial Species 

      Domingues, Sara; Harms, Klaus; Fricke, W. Florian; Johnsen, Pål Jarle; da Silva, Gabriela J.; Nielsen, Kåre M. (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      We have investigated to what extent natural transformation acting on free DNA substrates can facilitate transfer of mobile elements including transposons, integrons and/or gene cassettes between bacterial species. Naturally transformable cells of Acinetobacter baylyi were exposed to DNA from integron-carrying strains of the genera Acinetobacter, Citrobacter, Enterobacter, Escherichia, Pseudomonas, ...

    • Substitutions of short heterologous DNA segments of intragenomic or extragenomic origins produce clustered genomic polymorphisms 

      Harms, Klaus; Lunnan, Asbjørn; Hulter, Nils; Mourier, Tobias; Vinner, Lasse; Andam, Cheryl P; Marttinen, Pekka; Fridholm, Helena; Hansen, Anders Johannes; Hanage, William P; Nielsen, Kaare Magne; Willerslev, Eske; Johnsen, Pål Jarle (Journal article; Tidsskriftartikkel; Peer reviewed, 2016-12-27)
      In a screen for unexplained mutation events we identified a previously unrecognized mechanism generating clustered DNA polymorphisms such as microindels and cumulative SNPs. The mechanism, short-patch double illegitimate recombination (SPDIR), facilitates short single-stranded DNA molecules to invade and replace genomic DNA through two joint illegitimate recombination events. SPDIR is controlled by ...

    • Testing for the fitness benefits of natural transformation during community-embedded evolution 

      Winter, Macaulay; Harms, Klaus; Johnsen, Pål Jarle; Buckling, Angus; Vos, Michiel (Journal article; Tidsskriftartikkel; Peer reviewed, 2023-08-01)
      Natural transformation is a process where bacteria actively take up DNA from the environment and recombine it into their genome or reconvert it into extra-chromosomal genetic elements. The evolutionary benefits of transformation are still under debate. One main explanation is that foreign allele and gene uptake facilitates natural selection by increasing genetic variation, analogous to meiotic ...

    • Tn1 transposition in the course of natural transformation enables horizontal antibiotic resistance spread in Acinetobacter baylyi 

      Kloos, Julia Maria; Johnsen, Pål Jarle; Harms, Klaus (Journal article; Tidsskriftartikkel; Peer reviewed, 2020-12-03)
      Transposons are genetic elements that change their intracellular genomic position by transposition and are spread horizontally between bacteria when located on plasmids. It was recently discovered that transposition from fully heterologous DNA also occurs in the course of natural transformation. Here, we characterize the molecular details and constraints of this process using the replicative transposon ...

    • A Trade-off between the Fitness Cost of Functional Integrases and Long-term stability of Integrons 

      Starikova, Irina; Harms, Klaus; Haugen, Pål; Lunde, Tracy Munthali; Primicerio, Raul; Samuelsen, Ørjan; Nielsen, Kaare Magne; Johnsen, Pål Jarle (Journal article; Tidsskriftartikkel; Peer reviewed, 2012)
      Horizontal gene transfer (HGT) plays a major role in bacterial microevolution as evident from the rapid emergence and spread of antimicrobial drug resistance. Few studies have however addressed the population dynamics of newly imported genetic elements after HGT. Here, we show that newly acquired class-1 integrons from Salmonella enterica serovar Typhimurium and Acinetobacter baumannii, free of ...