title: Polyphasic detection of cyanobacteria in terrestrial biofilms.
abstract: Cyanobacterial populations detected on buildings by traditional methods are mainly filamentous, whereas direct microscopy shows that they are principally coccoid morphotypes that often cannot be isolated in culture, but may grow on artificial media when the spatial biofilm relationships are maintained. The polyphasic strategy described here was to select morphologically distinct colonies from rehydrated biofilms for direct DNA amplification, allowing uncultured organisms to be sequenced and their morphology to be characterized by microscopy. DNA data banks currently contain many entries for cyanobacteria of unrecorded morphology, which does not facilitate identification, although genetic variability in a population may be assessed. The sequence homologies of the present biofilm organisms (EMBL accession numbers AJ619681 to 619690) with those in DNA databanks were low, indicating differences between xerophytic cyanobacteria on walls and aquatic species comprising the majority in the databases. Further development of databases for the populations found in this environment, subject to temperature extremes, repeated desiccation and high UV and salt levels, is required.
authors.affiliation: Department of Biophysics Federal University of Rio Grande do Sul (UFRGS) Avenue Bento Gonçalves 9500 Porto Alegre--RS 91501-970 Brazil. cgaylarde@yahoo.com
authors.forename: Christine
authors.initials: C
authors.lastname: Gaylarde
authors.forename: Peter
authors.initials: P
authors.lastname: Gaylarde
authors.forename: Janine
authors.initials: J
authors.lastname: Copp
authors.forename: Brett
authors.initials: B
authors.lastname: Neilan
mesh_terms: D001483:Base Sequence; D018441:Biofilms / Q000254:growth & development; D001938:Brazil; D000458:Cyanobacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000502:physiology; D017931:DNA Primers / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics / Q000302:isolation & purification; D004783:Environmental Microbiology; D008969:Molecular Sequence Data; D010641:Phenotype; D016133:Polymerase Chain Reaction
chemical_list: D017931:DNA Primers; D004269:DNA, Bacterial