title: A Rich Morphological Diversity of Biosaline Drying Patterns Is Generated by Different Bacterial Species, Different Salts and Concentrations: Astrobiological Implications.
abstract: Biosaline formations (BSFs) are complex self-organized biomineral patterns formed by "hibernating" bacteria as the biofilm that contains them dries out. They were initially described in drying biofilms of Escherichia coli cells + NaCl. Due to their intricate 3-D morphology and anhydrobiosis, these biomineralogical structures are of great interest in astrobiology. Here we report experimental data obtained with various alkali halide salts (NaF, NaCl, NaBr, LiCl, KCl, CsCl) on BSF formation with E. coli and Bacillus subtilis bacteria at two saline concentrations: 9 and 18 mg/mL. Our results indicate that, except for LiCl, which is inactive, all the salts assayed are active during BSF formation and capable of promoting the generation of distinctive drying patterns at each salt concentration. Remarkably, the BSFs produced by these two bacterial species produce characteristic architectural hallmarks as the BSF dries. The potential biogenicity of these biosaline drying patterns is studied, and the astrobiological implications of these findings are discussed.
  
  
  
  Biosaline formations-Biosaline drying patterns-Escherichia coli-Bacillus subtilis-Bacterial biofilms-Morphological biosaline biosignatures-Morphoprinting-Dormant life. Astrobiology 16, 513-524.
authors.affiliation: 1 Laboratory of BioMineralogy and Astrobiological Research (LBMARS), Unidad Asociada UVA-CSIC , Edificio INDITI, Boecillo, Valladolid, Spain .|2 OAS-BioAstronomy Group, Observatorio Astronómico de Segurilla (OAS) , Segurilla, Toledo, Spain .
authors.forename: José María
authors.initials: JM
authors.lastname: Gómez Gómez
authors.affiliation: 1 Laboratory of BioMineralogy and Astrobiological Research (LBMARS), Unidad Asociada UVA-CSIC , Edificio INDITI, Boecillo, Valladolid, Spain .
authors.forename: Jesús
authors.initials: J
authors.lastname: Medina
authors.affiliation: 1 Laboratory of BioMineralogy and Astrobiological Research (LBMARS), Unidad Asociada UVA-CSIC , Edificio INDITI, Boecillo, Valladolid, Spain .
authors.forename: Fernando
authors.initials: F
authors.lastname: Rull
mesh_terms: D001412:Bacillus subtilis; D018407:Bacterial Physiological Phenomena; D018441:Biofilms; D003890:Desiccation; D004926:Escherichia coli; D018559:Exobiology; D009994:Osmolar Concentration; D012965:Sodium Chloride / Q000737:chemistry; D017670:Sodium Compounds / Q000737:chemistry*; D013045:Species Specificity
chemical_list: D017670:Sodium Compounds; D012965:Sodium Chloride