title: Antagonistic interactions and production of halocin antimicrobial peptides among extremely halophilic prokaryotes isolated from the solar saltern of Sfax, Tunisia.
abstract: Thirty-five extremely halophilic microbial strains isolated from crystallizer (TS18) and non-crystallizer (M1) ponds in the Sfax solar saltern in Tunisia were examined for their ability to exert antimicrobial activity. Antagonistic assays resulted in the selection of eleven strains that displayed such antimicrobial activity and they were further characterized. Three cases of cross-domain inhibition (archaea/bacteria or bacteria/archaea) were observed. Four archaeal strains exerted antimicrobial activity against several other strains. Three strains, for which several lines of evidence suggested the antimicrobial activity was, at least in part, due to peptide/protein agents (Halobacterium salinarum ETD5, Hbt. salinarum ETD8, and Haloterrigena thermotolerans SS1R12), were studied further. Optimal culture conditions for growth and antimicrobial production were determined. Using DNA amplification with specific primers, sequencing and RT-PCR analysis, Hbt. salinarum ETD5 and Hbt. salinarum ETD8 were shown to encode and express halocin S8, a hydrophobic antimicrobial peptide targeting halophilic archaea. Although the gene encoding halocin H4 was amplified from the genome of Htg. thermotolerans SS1R12, no transcript could be detected and the antimicrobial activity was most likely due to multiple antimicrobial compounds. This is also the first report that points to four different strains isolated from different geographical locations with the capacity to produce identical halocin S8 proteins.
authors.affiliation: Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR11ES/72), Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax, Tunisia.|Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245 CNRS-MNHN), Sorbonne Universités, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
authors.forename: Fadoua
authors.initials: F
authors.lastname: Ghanmi
authors.affiliation: Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245 CNRS-MNHN), Sorbonne Universités, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France. acarre@mnhn.fr.
authors.forename: Alyssa
authors.initials: A
authors.lastname: Carré-Mlouka
authors.affiliation: Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245 CNRS-MNHN), Sorbonne Universités, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
authors.forename: Manon
authors.initials: M
authors.lastname: Vandervennet
authors.affiliation: Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR11ES/72), Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax, Tunisia.
authors.forename: Ines
authors.initials: I
authors.lastname: Boujelben
authors.affiliation: Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR11ES/72), Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax, Tunisia.
authors.forename: Doniez
authors.initials: D
authors.lastname: Frikha
authors.affiliation: Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR11ES/72), Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax, Tunisia.
authors.forename: Habib
authors.initials: H
authors.lastname: Ayadi
authors.affiliation: Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245 CNRS-MNHN), Sorbonne Universités, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
authors.forename: Jean
authors.initials: J
authors.lastname: Peduzzi
authors.affiliation: Molécules de Communication et Adaptation des Microorganismes (MCAM, UMR 7245 CNRS-MNHN), Sorbonne Universités, Muséum national d'Histoire naturelle, Centre national de la Recherche scientifique (CNRS), CP 54, 57 rue Cuvier, 75005, Paris, France.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Rebuffat
authors.affiliation: Unité Biodiversité et Ecosystèmes Aquatiques Environnementaux (UR11ES/72), Faculté des Sciences de Sfax, Université de Sfax, BP 1171, 3000, Sfax, Tunisia.
authors.forename: Sami
authors.initials: S
authors.lastname: Maalej
mesh_terms: D000898:Antibiosis; D023181:Antimicrobial Cationic Peptides; D019843:Archaeal Proteins / Q000235:genetics / Q000378:metabolism*; D020745:Genome, Archaeal; D006216:Halobacteriaceae / Q000302:isolation & purification / Q000378:metabolism* / Q000502:physiology; D010455:Peptides / Q000235:genetics / Q000378:metabolism*; D000068357:Saline Waters; D055049:Salt Tolerance; D014871:Water Microbiology
chemical_list: D023181:Antimicrobial Cationic Peptides; D019843:Archaeal Proteins; D010455:Peptides; C413338:halocin S8
keywords: Antimicrobial peptides/proteins; Halocins; Halophilic archaea; Solar saltern