New in press
Bacillus subtilis DynA is a member of the dynamin superfamily, involved in membrane remodeling processes. DynA was shown to catalyze full membrane fusion and it plays a role in membrane surveillance against antibiotics. We show here that DynA also provides a novel resistance mechanism against phage infection. Cells lacking DynA are efficiently lysed after phage infection and virus replication. DynA does not prevent phage infection and replication in individual cells, but significantly delays host cell lysis, thereby slowing down the release of phage progeny from the host cells. During the process, DynA forms large, almost immobile clusters on the cell membrane that seem to support membrane integrity. Single-molecule tracking revealed a shift of freely diffusive molecules within the cytosol toward extended, confined motion at the cell membrane following phage induction. Thus, the bacterial dynamins are the first anti-phage system reported to delay host cell lysis and the last line of defense of a multilayered antiviral defense. DynA is therefore providing protective effects on the population, but not on single cell level.
DynA prevents host cell lysis after infection
a Fluorescent microscopy analysis of a mixed culture of a DynA-overexpressing strain (DynA-GFP induced by 1% xylose, cells expressing DynA are indicated by green fluorescence) and a DynA-deficient (ΔdynA) B. subtilis strain after infection with ɸ29 (phage DNA labeled with Hoechst dye and capsids labeled with Alexa Fluor 647). Time lapse analysis of the infection process reveals that shortly after addition of the labeled phages red foci appear next to the host cells and in few cases bright blue foci inside the host cells can be observed. Cells that are actively infected can be identified by the intracellular Hoechst DNA stain (blue). Cells with and without DynA are infected equally well. During the time course of the infection more of the cells lacking DynA lyse while cells expressing DynA remain intact.
b Zoom into an early infection where the Hoechst dye injection into the host cell is spatially close to a labeled capsid, indicating an ongoing infection process. Note that no DynA focus is present at the site of DNA injection Scale bar 1 μm.
c Quantification of bacterial lysis of DynA overexpressing (DynA++) and the deletion (ΔdynA) strains.
Guo L, Sattler, L, Shafqat S, Graumann PL, Bramkamp M
mBio, 2022 13 (1):e0375321, doi: 10.1128/mbio.03753-21.
Giacomelli G*, Feddersen H*, Peng F, Martins GB, Grafemeyer M, Meyer F, Mayer B, Graumann PL, Bramkamp M. Genes (Basel). 2022 Jan 30;13(2):278. doi: 10.3390/genes13020278
Osorio-Valeriano M, Altegoer F, Das CK, Steinchen W, Panis G, Connolley L, Giacomelli G, Feddersen H, Corrales-Guerrero L, Giammarinaro PI, Hanßmann J, Bramkamp M, Viollier PH, Murray S, Schäfer LV, Bange G, Thanbichler M.Mol Cell. 2021 Oct 7;81(19):3992-4007.e10. doi: 10.1016/j.molcel.2021.09.004
Zielińska A, Savietto A, de Sousa Borges A, Martinez D, Berbon M, Roelofsen JR, Hartman AM, de Boer R, van der Klei IJ, Hirsch AKH, Habenstein B, Bramkamp M, Scheffers D-J
Elife, 2020, 9:e57179. doi: 10.7554/eLife.57179
Böhm K, Giacomelli G, Schmidt A, Imhof A, Koszul R, Marbouty M, Bramkamp M
Nat Commun, 2020, 11(1):1485. doi: 10.1038/s41467–020–15238–4
Schubert K, Sieger B, Meyer F, Giacomelli G, Böhm K, Rieblinger A, Lindenthal L, Sachs N, Wanner G, Bramkamp M
mBio, 2017 Feb 7, vol. 8 no. 1 e02213-16. doi: 10.1128/mBio.02213-16
Sawant P, Eissenberger K, Karier L, Mascher T, Bramkamp M
Environ Microbiol, 2016, 18: 2705–2720. doi:10.1111/1462-2920.13110
Donovan C, Heyer A, Pfeifer E, Polen T, Wittmann A, Krämer R, Frunzke J, Bramkamp M
Nucleic Acids Res, 2015 Apr 27. pii: gkv374. doi: 10.1093/nar/gkv374
Bach JN, Bramkamp M
Mol Microbiol, 2013 Jun, 88(6):1205-17. doi: 10.1111/mmi.12252
Bramkamp M, Emmins R, Weston L, Donovan C, Daniel RA, Errington J
Mol Microbiol, 2008 Dec, 70(6):1556-69. doi: 10.1111/j.1365-2958.2008.06501.x
Researchers from MPI-EB Plön and Kiel University hope that the newly described species will provide a better understanding of the evolution of the genus Bacteroides as part of a healthy microbiota.
CAU press release: https://www.uni-kiel.de/en/university/details/news/142-unterweger-archmicrob
A research team from Kiel University describes how a bacterial dynamin protein is involved in a previously unknown protective mechanism against bacteriophage infections.
CAU press release: https://www.uni-kiel.de/en/university/details/news/021-bramkamp-mbio
Research teams from Kiel University’s Microbiology and the Universities of Amsterdam and Munich use imaging and modelling to explain why single bacterial cells do not always grow exponentially.
CAU press release: https://www.uni-kiel.de/en/university/details/news/251-meyer-elife
Interdisciplinary research teams from the Max-Planck-Institute of Biochemistry and the Institute of General Microbiology at Kiel University show that dynamic proteins can deform the cell membrane of bacterial cells and thus initiate cell division.
CAU press release: https://www.uni-kiel.de/en/university/details/news/124-ramirez-naturecomms
Research team in Kiel has identified the involvement of so-called flotillin proteins in the fluidization of bacterial cell membranes.
CAU press release: https://www.uni-kiel.de/en/university/details/news/173-zielinska-elife
Kiel research team investigates previously-unknown reproduction mechanism in the biotech-relevant bacterium Corynebacterium glutamicum.
CAU press release: https://www.uni-kiel.de/en/university/details/news/083-bramkamp-naturecomms
LMU press release about new insights into the control of DNA replication and cell division in Corynebacterium glutamicum, a biotechnologically important microorganism, could help to optimize the industrial production of amino acids.
LMU press release about the selective block of apical growth in CMN group bacteria caused by the antituberculosis drug Ethambutol. Ethambutol has long been part of the standard therapy for tuberculosis. LMU researchers now describe how the antibiotic acts on the bacterium that causes the disease: It specifically inhibits growth of the cell wall from the cell poles.