title: Multiparametric AFM reveals turgor-responsive net-like peptidoglycan architecture in live streptococci.
abstract: Cell-wall peptidoglycan (PG) of Gram-positive bacteria is a strong and elastic multi-layer designed to resist turgor pressure and determine the cell shape and growth. Despite its crucial role, its architecture remains largely unknown. Here using high-resolution multiparametric atomic force microscopy (AFM), we studied how the structure and elasticity of PG change when subjected to increasing turgor pressure in live Group B Streptococcus. We show a new net-like arrangement of PG, which stretches and stiffens following osmotic challenge. The same structure also exists in isogenic mutants lacking surface appendages. Cell aging does not alter the elasticity of the cell wall, yet destroys the net architecture and exposes single segmented strands with the same circumferential orientation as predicted for intact glycans. Together, we show a new functional PG architecture in live Gram-positive bacteria.
authors.affiliation: Department of Biological Chemistry, 8 Ulman Building, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Ron Saar
authors.initials: RS
authors.lastname: Dover
authors.affiliation: Department of Chemical Research Support, Surface Analysis Unit, Goldwurm Building, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Arkady
authors.initials: A
authors.lastname: Bitler
authors.affiliation: Department of Chemical Research Support, Electron Microscopy Unit, Issac Wolfson Building, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Eyal
authors.initials: E
authors.lastname: Shimoni
authors.affiliation: Department of Microbiology, Institut Pasteur, Unité de Biologie des Bactéries Pathogènes à Gram-Positif, CNRS ERL3526, Paris 75015, France.
authors.forename: Patrick
authors.initials: P
authors.lastname: Trieu-Cuot
authors.affiliation: Department of Biological Chemistry, 8 Ulman Building, The Weizmann Institute of Science, Rehovot 76100, Israel.
authors.forename: Yechiel
authors.initials: Y
authors.lastname: Shai
mesh_terms: D049108:Cell Enlargement; D048430:Cell Shape; D002473:Cell Wall / Q000737:chemistry / Q000502:physiology*; D016922:Cellular Senescence / Q000502:physiology; D004548:Elasticity / Q000502:physiology*; D018625:Microscopy, Atomic Force; D010457:Peptidoglycan / Q000737:chemistry / Q000378:metabolism*; D011312:Pressure; D013292:Streptococcus agalactiae / Q000737:chemistry / Q000502:physiology*
chemical_list: D010457:Peptidoglycan