title: Manipulating each MreB of Bdellovibrio bacteriovorus gives diverse morphological and predatory phenotypes.
abstract: We studied the two mreB genes, encoding actinlike cytoskeletal elements, in the predatory bacterium Bdellovibrio bacteriovorus. This bacterium enters and replicates within other Gram-negative bacteria by attack-phase Bdellovibrio squeezing through prey outer membrane, residing and growing filamentously in the prey periplasm forming an infective "bdelloplast," and septating after 4 h, once the prey contents are consumed. This lifestyle brings challenges to the Bdellovibrio cytoskeleton. Both mreB genes were essential for viable predatory growth, but C-terminal green fluorescent protein tagging each separately with monomeric teal-fluorescent protein (mTFP) gave two strains with phenotypic changes at different stages in predatory growth and development. MreB1-mTFP cells arrested growth early in bdelloplast formation, despite successful degradation of prey nucleoid. A large population of stalled bdelloplasts formed in predatory cultures and predation proceeded very slowly. A small proportion of bdelloplasts lysed after several days, liberating MreB1-mTFP attack-phase cells of wild-type morphology; this process was aided by subinhibitory concentrations of an MreB-specific inhibitor, A22. MreB2-mTFP, in contrast, was predatory at an almost wild-type rate but yielded attack-phase cells with diverse morphologies, including spherical, elongated, and branched, the first time such phenotypes have been described. Wild-type predatory rates were seen for all but spherical morphotypes, and septation of elongated morphotypes was achieved by the addition of A22.
authors.affiliation: Institute of Genetics, School of Biology, Medical School, University of Nottingham, Derby Road, QMC, Nottingham NG7 2UH, United Kingdom.
authors.forename: Andrew Karl
authors.initials: AK
authors.lastname: Fenton
authors.forename: Carey
authors.initials: C
authors.lastname: Lambert
authors.forename: Peter Charles
authors.initials: PC
authors.lastname: Wagstaff
authors.forename: Renee Elizabeth
authors.initials: RE
authors.lastname: Sockett
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism*; D001501:Bdellovibrio / Q000166:cytology* / Q000235:genetics / Q000378:metabolism*; D003598:Cytoskeletal Proteins / Q000235:genetics* / Q000378:metabolism*; D017353:Gene Deletion; D050296:Microbial Viability; D008853:Microscopy; D008854:Microscopy, Electron; D008954:Models, Biological; D010641:Phenotype
chemical_list: D001426:Bacterial Proteins; D003598:Cytoskeletal Proteins