TY  - JOUR
A1  - Dunsing, Valentin
A1  - Irmscher, Tobias
A1  - Barbirz, Stefanie
A1  - Chiantia, Salvatore
T1  - Purely Polysaccharide-Based Biofilm Matrix Provides Size-Selective Diffusion Barriers for Nanoparticles and Bacteriophages
JF  - Biomacromolecules : an interdisciplinary journal focused at the interface of polymer science and the biological sciences
N2  - Biofilms are complex mixtures of proteins, DNA, and polysaccharides surrounding bacterial communities as protective barriers that can be biochemically modified during the bacterial life cycle. However, their compositional heterogeneity impedes a precise analysis of the contributions of individual matrix components to the biofilm structural organization. To investigate the structural properties of glycan-based biofilms, we analyzed the diffusion dynamics of nanometer-sized objects in matrices of the megadalton-sized anionic polysaccharide, stewartan, the major biofilm component of the plant pathogen, Pantoea stewartii. Fluorescence correlation spectroscopy and single-particle tracking of nanobeads and bacteriophages indicated notable subdiffusive dynamics dependent on probe size and stewartan concentration, in contrast to free diffusion of small molecules. Stewartan enzymatic depolymerization by bacteriophage tailspike proteins rapidly restored unhindered diffusion. We, thus, hypothesize that the glycan polymer stewartan determines the major physicochemical properties of the biofilm, which acts as a selective diffusion barrier for nanometer-sized objects and can be controlled by enzymes.
Y1  - 2019
U6  - https://doi.org/10.1021/acs.biomac.9b00938
SN  - 1525-7797
SN  - 1526-4602
VL  - 20
IS  - 10
SP  - 3842
EP  - 3854
PB  - American Chemical Society
CY  - Washington
ER  - 
TY  - GEN
A1  - Dunsing, Valentin
A1  - Irmscher, Tobias
A1  - Barbirz, Stefanie
A1  - Chiantia, Salvatore
T1  - Microviscosity of bacterial biofilm matrix characterized by fluorescence correlation spectroscopy and single particle tracking
T2  - European biophysics journal : with biophysics letters ; an international journal of biophysics
Y1  - 2019
U6  - https://doi.org/https://doi.org/10.1007/s00249-019-01373-4
SN  - 0175-7571
SN  - 1432-1017
VL  - 48
SP  - S115
EP  - S115
PB  - Springer
CY  - New York
ER  - 
TY  - JOUR
A1  - Broeker, Nina K.
A1  - Roske, Yvette
A1  - Valleriani, Angelo
A1  - Stephan, Mareike Sophia
A1  - Andres, Dorothee
A1  - Koetz, Joachim
A1  - Heinemann, Udo
A1  - Barbirz, Stefanie
T1  - Time-resolved DNA release from an O-antigen-specific Salmonella bacteriophage with a contractile tail
JF  - The journal of biological chemistry
N2  - Myoviruses, bacteriophages with T4-like architecture, must contract their tails prior to DNA release. However, quantitative kinetic data on myovirus particle opening are lacking, although they are promising tools in bacteriophage-based antimicrobial strategies directed against Gram-negative hosts. For the first time, we show time-resolved DNA ejection from a bacteriophage with a contractile tail, the multi-O-antigen-specific Salmonella myovirus Det7. DNA release from Det7 was triggered by lipopolysaccharide (LPS) O-antigen receptors and notably slower than in noncontractile-tailed siphoviruses. Det7 showed two individual kinetic steps for tail contraction and particle opening. Our in vitro studies showed that highly specialized tailspike proteins (TSPs) are necessary to attach the particle to LPS. A P22-like TSP confers specificity for the Salmonella Typhimurium O-antigen. Moreover, crystal structure analysis at 1.63 angstrom resolution confirmed that Det7 recognized the Salmonella Anatum O-antigen via an E15-like TSP, DettilonTSP. DNA ejection triggered by LPS from either host showed similar velocities, so particle opening is thus a process independent of O-antigen composition and the recognizing TSP. In Det7, at permissive temperatures TSPs mediate O-antigen cleavage and couple cell surface binding with DNA ejection, but no irreversible adsorption occurred at low temperatures. This finding was in contrast to short-tailed Salmonella podoviruses, illustrating that tailed phages use common particle-opening mechanisms but have specialized into different infection niches.
KW  - bacteriophage
KW  - lipopolysaccharide (YLPS)
KW  - structural biology
KW  - DNA viruses
KW  - glycobiology
KW  - fluorescence
KW  - Salmonella enterica
KW  - contractile tail
KW  - DNA ejection
KW  - O-antigen specificity
KW  - Salmonella myovirus
KW  - tailspike protein
KW  - molecular machine
Y1  - 2019
U6  - https://doi.org/10.1074/jbc.RA119.008133
SN  - 1083-351X
VL  - 294
IS  - 31
SP  - 11751
EP  - 11761
PB  - American Society for Biochemistry and Molecular Biology
CY  - Bethesda
ER  -