We study antimicrobial peptides (bacteriociner) which can be used to combat different antibiotic resistant, pathogenic bacteria such as staphylococci, streptococci, Listeria and enterococci. 

  • Bacteriocins

    We are studying antimicrobial peptides, also known as bacteriocins. Bacteriocins with different structures and functions are common in nature. We are studying these molecules from a fundamental and applied perspective.

    The fundamental perspectives include how bacteriocins are produced, which genes that are involved in their biosynthesis, how production is regulated, how the bacteriocins bind and kill target cells and structure-function relationships of these peptides. We are also interested in the ecological role of these peptides.

    Such studies are important as a basis for the development of bacteriocins as safe and effective applications. Our applied research focuses on the development of bacteriocins as natural preservatives and as drugs to fight antibiotic resistant pathogens and biofilm formation.

    Antibiotic targets

    Gene technology methods

  • Preprints:

    Barbuti MD, Lambert E, Myrbråten IS, Ducret A, Stamsås GAH, Wilhelm L, Liu X, Salehian Z, Veening JW, Straume D, Grangeasse C, Perez C, Kjos M. The function of CozE proteins is linked to lipoteichoic acid biosynthesis in Staphylococcus aureushttps://www.biorxiv.org/content/10.1101/2023.10.20.563254v1

    Liu X*, de Bakker V*, Heggenhougen MV*, Frøynes Heidal A, Mårli MT, Porcellato D, Veening JW, Kjos M. Genome-wide CRISRPi-seq screen in Staphylococcus aureus reveals resistance determinants for resistance to a lipoglycopeptide antibiotic. https://www.biorxiv.org/content/10.1101/2023.08.30.555613v1  

    List of publications:

    Wolden R, Ovchinnikov KV, Venter HJ, Oftedal TF, Diep DB, Cavanagh JP (2023). The novel bacteriocin romsacin from Staphylococcus haemolyticus inhibits Gram-positive WHO priority pathogens. Microbiol Spectr. 2023 Oct 31:e0086923. doi: 10.1128/spectrum.00869-23.

    Cacace E, Kim V, Knopp M, Tietgen M, Brauer-Nikonow A, Inecik K, Mateus A, Milanese A, Mårli MT, Mitosch K, Selkrig J, Brochado AR, Kuipers O, Kjos M, Zeller G, Savitski M, Göttig S, Huber W, Typas A (2023) High-throughput profiling of drug interactions in Gram-positive bacteria. Preprint: https://www.biorxiv.org/content/10.1101/2022.12.23.521747v1.

    Hauge IH, Sandegren V, Ruud Winther A, Bøe CA, Salehian Z, Håvarstein LS, Kjos M, Straume D (2023) A novel proteinaceous molecule produced by Lysinibacillus sp. OF-1 depends on the Ami oligopeptide transporter to kill Streptococcus pneumoniae. Microbiology. 169(3):001313. https://doi.org/10.1099/mic.0.001313

    Disen Barbuti M, Myrbråten I, Morales Angeles D, Kjos M (2022) An updated overview of the cell cycle promesses in Staphylococcus aureus. MicrobiologyOpen. In press. doi.org/10.1002/mbo3.1338

    Gao Y, Kjos M, Arntzen MØ, Bakken LR, Frostegård Å (2023) Denitrification by bradyrhizobia under feast and famine and the role of the bc1 complex in securing electrons for N2O reduction. Appl Environ Microbiol. https://doi.org/10.1128/aem.01745-22 Preprint : https://www.biorxiv.org/content/10.1101/2022.09.29.510233v1

    Audshasai T, Coles JA, Panagiotou S, Khandaker S, Scales HE, Kjos M, Baltazar M, Vignau, Brewer JM, Kadioglu A, Yang M (2022). Streptococcus pneumoniae rapidly translocates from the nasopharynx through the cribriform plate to invade and inflame the dura. mBio. 3(4):e0102422. doi.org/10.1128/mbio.01024-22

    Myrbråten I, Stamsås GA, Chan H, Morales Angeles D, Knutsen TM, Salehian Z, Shapaval O, Straume D, Kjos M. (2022) SmdA is a novel cell morphology determinant in Staphylococcus aureusmBiodoi.org/10.1128/mbio.03404-21. Commentary: doi.org/10.1128/mbio.00737-22

    Gallay C, Sanselicio S, Anderson ME, Soh YM, Liu X, Stamsås GA, Pelliciari S, van Raaphorst R, Dénéréaz J, Kjos M, Murray H, Gruber S, Grossman AD, Veening JW (2021). CcrZ is a spatiotemporal cell cycle regulator that interacts with FtsZ and controls DNA replication by modulating the activity of DnaA. Nat Microbiol. doi.org/10.1038/s41564-021-00949-1Commentary.

    Ovchinnikov K, Kranjec C, Telke A, Kjos M, Thorstensen T, Carlsen H, Scherer S, Diep DB (2021). A strong synergy between the thiopeptide bacteriocin micrococcin P1 and rifampicin against MRSA in a murine skin infection model . Front Immunol. 12: 676534. doi.org/10.3389/fimmu.2021.676534

    40. Straume D, Piechowiak KW, Kjos M, Håvarstein LS (2021) Class A PBPs: it is time to rethink traditional paradigms. Mol Microbiol. doi: https://doi.org/10.1111/mmi.14714

    Ruud-Winther A, Kjos M, Herigstad ML, Håvarstein LS, Straume D (2021). EloR interacts with the lytic transglycosylase MltG at midcell in Streptococcus pneumoniae R6. J Bacteriol. doi: 10.1128/JB.00691-20. Preprint: https://www.biorxiv.org/content/10.1101/2020.12.18.423453v1.full

    Kranjec C*, Morales-Angeles D*, Torrissen Mårli M, Fernandez L, Garcia P, Kjos M*, Diep DB*. (2021) Staphylococcal Biofilms: Challenges and novel therapeutic perspectives. Antibiotics. 10(2):131. https://doi.org/10.3390/antibiotics10020131

    Stamsås GA*, Restelli M*, Ducret A, Freton C, Garcia PS, Håvarstein LS, Straume D, Grangeasse C and Kjos M (2020) A CozE homologue contributes to cell size homeostasis of Streptococcus pneumoniae. mBio. 11(5):e02461-20. https://doi.org/10.1128/mBio.02461-20

    Fergestad M, Stamsås GA, Morales-Angeles D, Salehian Z, Wasteson Y, Kjos M (2020) PBP2A provides variable levels of protection towards different β-lactams in Staphylococcus aureus RN4220. Microbiol Open. https://doi.org/10.1002/mbo3.1057

    Straume D, Piechowiak KW, Olsen S, Stamsås GA, Berg KH, Kjos M, Heggenhougen MV, Alcorlo M, Hermoso J and Håvarstein LS. Class A PBPs have a distinct and unique role in the construction of the pneumococcal cell wall. Proc Natl Acad Sci U S A. doi.org/10.1073/pnas.1917820117. Preprint available at: https://www.biorxiv.org/content/10.1101/665463v1.

    van Raaphorst R, Kjos M, Veening JW (2019) BactMAP: an R package for integrating, analyzing and visualizing bacterial microscopy data. Mol Microbiol. Preprint available at: https://www.biorxiv.org/content/10.1101/728782v1

    Myrbråten I, Wiull K, Straume D, Salehian Z, Håvarstein LS, Mathiesen G, Kjos M (2019) CRISPR interference for rapid knockdown of essential cell cycle genes in Lactobacillus plantarummSphere. 4(2):e00007-19. Editor's pick.

    Ruud Winther A, Kjos M, Stamsås GA, Håvarstein LS, Straume D (2019) Prevention of EloR/KhpA heterodimerization by introduction of site-specific amino acid substitutions renders the essential elongasome protein PBP2b redundant in Streptococcus pneumoniaeSci Rep. 9:3681.  

    Kjos M. Transcriptional knockdown in pneumococci using CRISPR interference (2019) In: Streptococcus pneumoniae. Methods and Protocols (Iovino F, eds.), Methods in Molecular Biology Springer Protocols, Germany. 1968:89-98. doi: 10.1007/978-1-4939-9199-0_8.

    30. Kjos M. Construction of fluorescent pneumococci for in vivo imaging and labelling of the chromosome (2019) In: Streptococcus pneumoniae. Methods and Protocols (Iovino F, eds.), Methods in Molecular Biology Springer Protocols, Germany. 1968:41-51. doi: 10.1007/978-1-4939-9199-0_4.

    Lycus P, Soriano-Laguna M, Kjos M, Richardson D, Gates A, Milligan DA, Frostegård Å, Bergaust L, Bakken LR (2018) A bet-hedging strategy of denitrifying bacteria curtails their release of N2O. Proc Natl Acad Sci U S A. 115(46):11820-11825.

    Miller E*, Kjos M*, Abrudan M, Roberts IS, Veening JW, Rozen DE (2018) Crosstalk and eavesdropping among quorum sensing peptide signals that regulate bacteriocin production in Streptococcus pneumoniaeISME J. 12(10):2363-2375. Preprint available at: http://biorxiv.org/content/early/2016/11/11/087247. Se også: 1.

    Stamsås GA*, Myrbråten I*, Straume D, Salehian Z, Veening JW, Håvarstein LS, Kjos M (2018) CozEa and CozEb play overlapping and essential roles in controlling cell division in Staphylococcus aureusMol Microbiol. 109(5):615-632. Preprint available at: https://www.biorxiv.org/content/early/2018/05/23/256560. Se også: Cover

    Moreno-Gámez S, Sorg RA, Domenech A, Kjos M, Weissing FJ, van Doorn GS, Veening JW. Quorum-sensing integrates environmental cues, cell density and cell history to control bacterial competence. Nat Comm. 8(1):854.

    Stamsås GS, Straume D, Ruud Winther A, Kjos M, Frantzen CA, Håvarstein LS (2017) Identification of EloR (Spr1851) as a regulator of cell elongation in Streptococcus pneumoniaeMol Microbiol. 10.1111/mmi.13748

    van Raaphorst R*, Kjos M*, Veening JW (2017) Chromosome segregation drives division site selection in Streptococcus pneumoniaeProc Natl Acad Sci U S A. 114(29):E5959-E5968. *joint first authors. Se også: 1,2.

    Liu X, Gallay C, Kjos M, Domenech A, Slager J, van Kessel S, Knoops K, Sorg RA, Zhang JR, Veening JW (2017) High-throughput CRISPRi phenotyping in Streptococcus pneumoniae identifies new essential genes involved in cell wall synthesis and competence development. Mol Syst Biol. 13:931.

    Oppegård C, Kjos M, Veening JW, Nissen-Meyer J, Kristensen T (2016) A putative amino acid transporter determines sensitivity to the two-peptide bacteriocin plantaricin JK. MicrobiologyOpen. doi: 10.1002/mbo3.36.

    Kjos M*, Miller E*, Slager J, Lake F, Gericke O, Roberts IS, Rozen DE, Veening JW (2016) Antibiotic-induced expression of pneumococcal bacteriocins via regulatory interplay with the competence system. PLoS Pathogens. 12(2):e1005422. *joint first authors.

    Nourikyan J*, Kjos M*, Cluzel C, Morlot C, Mercy C, Noirot-Gros MF, Lavergne JP, Guiral S, Veening JW, Grangeasse C. (2015) Autophosphorylation of the bacterial tyrosine kinase CpsD coordinates capsule synthesis and cell division of Streptococcus pneumoniaePLoS Genetics. 11(9):e1005518. *joint first authors.

    Beilharz K, van Raaphorst R, Kjos M, Veening JW (2015) Red fluorescent proteins for gene expression and protein localization studies in Streptococcus pneumoniae and efficient transformation with DNA assembled via the Gibson assembly method. Appl Environ Microbiol. 81(20):7244-52.

    Attaiech L, Minnen A, Kjos M, Gruber S, Veening JW (2015) The ParB-parS chromosome segregation system modulates natural competence development in Streptococcus pneumoniaemBio. 6(4):e00662-15.

    Paixão L, Oliveira J, Verissímo A, Vinga S, Lourenço E, Ventura R, Kjos M, Veening JW, Fernandes VE, Andrew PE, Yesilkaya H and Neves AR (2015) Host glycan sugar specific pathways in Streptococcus pneumoniae: galactose as a key sugar in colonisation and infection. PLoS One. 10(3):e0121042.

    16. Kjos M, Aprianto R, Fernandes VE, Andrew PW, van Strijp JAG, Nijland R, Veening JW (2015) Bright fluorescent Streptococcus pneumoniae for live cell imaging of host-pathogen interactions. J Bacteriol. 197:807-18.

    15. Kjos M*, Oppegård C*, Diep DB, Nes IF, Veening JW, Nissen-Meyer J, Kristiansen T (2014) Sensitivity to the two-peptide bacteriocin lactococcin G is dependent on an enzyme involved in cell-wall synthesis. Mol Microbiol. 92(6):1177-87. *joint first authors.

    Slager J, Kjos M, Attaiech L, Veening JW (2014) Antibiotic-induced increase of origin proximal gene copy number triggers bacterial competence. Cell. 157(2):395-406.

    Kjos M, Veening JW (2014) Tracking of chromosome dynamics in live Streptococcus pneumoniae reveals that transcription promotes chromosome segregation. Mol Microbiol. 91(6):1088-1105.

    Hassan M, Kjos M, Nes IF, Diep DB, Lotfipour F (2014) Antimicrobial peptides from prokaryotes. In: Novel Antimicrobial Agents and Strategies (Phoenix DA, Harris F, Dennison SR, eds.). Wiley-VCH, Germany.

    Pinho MG, Kjos M, Veening JW (2013) How to get (a)round: Mechanisms controlling growth and division of coccoid bacteria. Nat Rev Microbiol. 11:601-14.

    Hassan M, Kjos M, Nes IF, Diep DB, Lotfipour F (2012) Natural antimicrobial peptides from bacteria: characteristics and potential applications to fight against antibiotic resistance. J Appl Microbiol. 113(4):723-36.

    Nes IF, Kjos M, Diep DB (2011) Antimicrobial components of lactic acid bacteria. In: Lactic acid bacteria: microbiological and functional aspects, fourth edition (Lahtinen S, Ouwehand AC, Salminen S, von Wright A, eds.), CRC Press Taylor & Francis, USA.

    Kjos M, Borrero J, Opsata M, Birri DJ, Holo H, Cintas LM, Snipen L, Hernandez PE, Nes IF, Diep DB (2011) Target recognition, resistance, immunity and genome mining of class II bacteriocins from Gram-positive bacteria. Microbiology. 157:3256-67.

    Kjos M, Nes IF, Diep DB (2011) Mechanisms of resistance to bacteriocins targeting the mannose phosphotransferase system. Appl Environ Microbiol. 77(10):3335-42.

    Kjos M, Salehian Z, Nes IF, Diep DB (2010) An extracellular loop of the mannose phosphotransferase system component IIC is responsible for specific targeting by class IIa bacteriocins. J Bacteriol. 192(22):5906-13.

    5. Kjos M, Snipen LS, Salehian Z, Nes IF, Diep DB (2010) The Abi proteins and their involvement in bacteriocin self-immunity. J Bacteriol. 192(8):2068-76.

    Kjos M, Nes IF, Diep DB (2009) Class II one-peptide bacteriocins target a phylogenetically defined subgroup of mannose phosphotransferase systems on sensitive cells. Microbiology. 155(9):2949-61.

    Diep DB, Straume D, Kjos M, Torres C, Nes IF (2009) An overview of the mosaic bacteriocin pln loci from Lactobacillus plantarumPeptides 30 (8): 1562-74.

    Kjos M, Straume D, Nes IF, Diep DB (2009) Transposition of IS10R in Lactococcus lactisJ Appl Microbiol 106(1):288-95.

    Straume D, Kjos M, Nes IF, Diep DB (2007) Quorum-sensing based bacteriocin production is down-regulated by N-terminally truncated species of gene activators. Mol Genet Gen. 278 (3): 283-93.

    Master students:

    • Maren Sofie Foss Gulliksen
    • Anne-Line Bakke