title: Functions of S-layers.
abstract: Although S-layers are being increasingly identified on Bacteria and Archaea, it is enigmatic that in most cases S-layer function continues to elude us. In a few instances, S-layers have been shown to be virulence factors on pathogens (e.g. Campylobacter fetus ssp. fetus and Aeromonas salmonicida), protective against Bdellovibrio, a depository for surface-exposed enzymes (e.g. Bacillus stearothermophilus), shape-determining agents (e.g. Thermoproteus tenax) and nucleation factors for fine-grain mineral development (e.g. Synechococcus GL 24). Yet, for the vast majority of S-layered bacteria, the natural function of these crystalline arrays continues to be evasive. The following review up-dates the functional basis of S-layers and describes such diverse topics as the effect of S-layers on the Gram stain, bacteriophage adsorption in lactobacilli, phagocytosis by human polymorphonuclear leukocytes, the adhesion of a high-molecular-mass amylase, outer membrane porosity, and the secretion of extracellular enzymes of Thermoanaerobacterium. In addition, the functional aspect of calcium on the Caulobacter S-layer is explained.
authors.affiliation: Department of Microbiology, College of Biological Science, University of Guelph, Canada. tjb@micro.uoguelph.ca
authors.forename: T J
authors.initials: TJ
authors.lastname: Beveridge
authors.forename: P H
authors.initials: PH
authors.lastname: Pouwels
authors.forename: M
authors.initials: M
authors.lastname: Sára
authors.forename: A
authors.initials: A
authors.lastname: Kotiranta
authors.forename: K
authors.initials: K
authors.lastname: Lounatmaa
authors.forename: K
authors.initials: K
authors.lastname: Kari
authors.forename: E
authors.initials: E
authors.lastname: Kerosuo
authors.forename: M
authors.initials: M
authors.lastname: Haapasalo
authors.forename: E M
authors.initials: EM
authors.lastname: Egelseer
authors.forename: I
authors.initials: I
authors.lastname: Schocher
authors.forename: U B
authors.initials: UB
authors.lastname: Sleytr
authors.forename: L
authors.initials: L
authors.lastname: Morelli
authors.forename: M L
authors.initials: ML
authors.lastname: Callegari
authors.forename: J F
authors.initials: JF
authors.lastname: Nomellini
authors.forename: W H
authors.initials: WH
authors.lastname: Bingle
authors.forename: J
authors.initials: J
authors.lastname: Smit
authors.forename: E
authors.initials: E
authors.lastname: Leibovitz
authors.forename: M
authors.initials: M
authors.lastname: Lemaire
authors.forename: I
authors.initials: I
authors.lastname: Miras
authors.forename: S
authors.initials: S
authors.lastname: Salamitou
authors.forename: P
authors.initials: P
authors.lastname: Béguin
authors.forename: H
authors.initials: H
authors.lastname: Ohayon
authors.forename: P
authors.initials: P
authors.lastname: Gounon
authors.forename: M
authors.initials: M
authors.lastname: Matuschek
authors.forename: S F
authors.initials: SF
authors.lastname: Koval
mesh_terms: D000034:Abortion, Veterinary / Q000276:immunology / Q000382:microbiology; D000595:Amino Acid Sequence; D000818:Animals; D001105:Archaea / Q000502:physiology / Q000648:ultrastructure; D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000648:ultrastructure; D001422:Bacterial Adhesion; D001425:Bacterial Outer Membrane Proteins / Q000235:genetics / Q000502:physiology*; D018407:Bacterial Physiological Phenomena; D002169:Campylobacter Infections / Q000276:immunology / Q000382:microbiology / Q000662:veterinary; D002462:Cell Membrane / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D002473:Cell Wall / Q000737:chemistry / Q000502:physiology / Q000648:ultrastructure; D003460:Crystallization; D056890:Eukaryota / Q000502:physiology; D005260:Female; D006801:Humans; D008969:Molecular Sequence Data; D010587:Phagocytosis; D011247:Pregnancy; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid; D012756:Sheep; D012757:Sheep Diseases / Q000276:immunology / Q000382:microbiology; D013045:Species Specificity; D014774:Virulence
chemical_list: D001425:Bacterial Outer Membrane Proteins