title: Biofilm formation by group A Streptococcus: a role for the streptococcal regulator of virulence (Srv) and streptococcal cysteine protease (SpeB).
abstract: Recently, biofilms have become a topic of interest in the study of the human pathogen group A Streptococcus (GAS). In this study, we sought to learn more about the make-up of these structures and gain insight into biofilm regulation. Enzymic studies indicated that biofilm formation by GAS strain MGAS5005 required an extracellular protein and DNA component(s). Previous results indicated that inactivation of the transcriptional regulator Srv in MGAS5005 resulted in a significant decrease in virulence. Here, inactivation of Srv also resulted in a significant decrease in biofilm formation under both static and flow conditions. Given that production of the extracellular cysteine protease SpeB is increased in the srv mutant, we tested the hypothesis that increased levels of active SpeB may be responsible for the reduction in biofilm formation. Western immunoblot analysis indicated that SpeB was absent from MGAS5005 biofilms. Complementation of MGAS5005Deltasrv restored the biofilm phenotype and eliminated the overproduction of active SpeB. Inhibition of SpeB with E64 also restored the MGAS5005Deltasrv biofilm to wild-type levels.
authors.affiliation: Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Doern
authors.affiliation: Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: Amity L
authors.initials: AL
authors.lastname: Roberts
authors.affiliation: Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: Wenzhou
authors.initials: W
authors.lastname: Hong
authors.affiliation: Salem College, Winston-Salem, NC 27101, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Nelson
authors.affiliation: Mary Babb Randolph Cancer Center, School of Medicine, West Virginia University, Morgantown, WV 26506, USA.|Department of Microbiology, Immunology and Cell Biology, West Virginia University, Morgantown, WV 26506, USA.
authors.forename: Slawomir
authors.initials: S
authors.lastname: Lukomski
authors.affiliation: Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: William E
authors.initials: WE
authors.lastname: Swords
authors.affiliation: Department of Microbiology and Immunology, Wake Forest University School of Medicine, Winston-Salem, NC 27157, USA.
authors.forename: Sean D
authors.initials: SD
authors.lastname: Reid
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000502:physiology*; D018441:Biofilms / Q000254:growth & development*; D003470:Culture Media; D005098:Exotoxins / Q000235:genetics / Q000502:physiology*; D015964:Gene Expression Regulation, Bacterial; D005809:Genes, Regulator; D006801:Humans; D008855:Microscopy, Electron, Scanning; D009154:Mutation; D013297:Streptococcus pyogenes / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism / Q000472:pathogenicity; D014774:Virulence / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D003470:Culture Media; D005098:Exotoxins; C027951:erythrogenic toxin