title: Extended phenotype of an mreB-like mutant in Azospirillum brasilense.
abstract: Tn5 mutagenesis was used to generate an Azospirillum brasilense SPF94 mutant. Genetic analysis of this mutant revealed that a homologue of the mreB gene, which controls cell shape in Bacillus subtilis and Escherichia coli, was inactivated. The cell-surface properties of the mutant were different from those of the parental strain. The mutant colonies were highly fluorescent when grown on plates containing Calcofluor White. Light and electron microscopy revealed that the mutant cells were round and had thicker capsules than the spiral parental strain. The mutants contained up to ten times more capsule protein than the parental strain, but lacked a 40 kDa protein that is abundant in the parental strain. The phenotype of the isolated mutant resembled that of the cyst-like differentiated forms of Azospirillum, suggesting that the mreB homologue could be involved in differentiation.
authors.affiliation: Dip. Biologia Animale e Genetica, Università di Firenze, 50125 Firenze, Italy.
authors.forename: Emanuele G
authors.initials: EG
authors.lastname: Biondi
authors.affiliation: Dip. Agrobiologia e Agrochimica, Università della Tuscia, 01100 Viterbo, Italy.
authors.forename: Francesca
authors.initials: F
authors.lastname: Marini
authors.affiliation: Dip. Scienze Biochimiche, Università 'La Sapienza', 00185 Roma, Italy.
authors.forename: Fabio
authors.initials: F
authors.lastname: Altieri
authors.affiliation: Dip. Biologia Vegetale, Università di Firenze, 50100 Firenze, Italy.
authors.forename: Laura
authors.initials: L
authors.lastname: Bonzi
authors.affiliation: Dip. Biologia Animale e Genetica, Università di Firenze, 50125 Firenze, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Bazzicalupo
authors.affiliation: Dip. Biologia di Base e Applicata, Università dell'Aquila, Via Vetoio, Coppito, 67100 L'Aquila, Italy.
authors.forename: Maddalena
authors.initials: M
authors.lastname: Del Gallo
mesh_terms: D000595:Amino Acid Sequence; D015806:Azospirillum brasilense / Q000235:genetics / Q000254:growth & development* / Q000502:physiology; D001422:Bacterial Adhesion; D016667:Bacterial Capsules / Q000378:metabolism; D001557:Benzenesulfonates / Q000378:metabolism; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D005456:Fluorescent Dyes / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D008854:Microscopy, Electron; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D010641:Phenotype
chemical_list: D001557:Benzenesulfonates; D004251:DNA Transposable Elements; D029968:Escherichia coli Proteins; D005456:Fluorescent Dyes; C078473:MreB protein, E coli; C007061:C.I. Fluorescent Brightening Agent 28