Open Access. Powered by Scholars. Published by Universities.®
Articles 1 - 3 of 3
Full-Text Articles in Microbiology
The Evolution Of Reduced Microbial Killing, Jan A.C. Vriezen Dr., Michael Valliere, Margaret A. Riley Dr.
The Evolution Of Reduced Microbial Killing, Jan A.C. Vriezen Dr., Michael Valliere, Margaret A. Riley Dr.
Jan A.C. Vriezen Dr.
Bacteria engage in a never-ending arms race in which they compete for limited resources and niche space. The outcome of this intense interaction is the evolution of a powerful arsenal of biological weapons. Perhaps the most studied of these are colicins, plasmid-based toxins produced by and active against Escherichia coli. The present study was designed to explore the molecular responses of a colicin-producing strain during serial transfer evolution. What evolutionary changes occur when colicins are produced with no target present? Can killing ability be maintained in the absence of a target? To address these, and other, questions, colicinogenic strains and …
The Role Of Sos Boxes In Enteric Bacteriocin Regulation, Jan A.C. Vriezen Dr., Osnat Gillor Dr., Margaret A. Riley Dr.
The Role Of Sos Boxes In Enteric Bacteriocin Regulation, Jan A.C. Vriezen Dr., Osnat Gillor Dr., Margaret A. Riley Dr.
Jan A.C. Vriezen Dr.
Bacteriocins are a large and functionally diverse family of toxins found in all major lineages of Bacteria. Colicins, those bacteriocins produced by Escherichia coli, serve as a model system for investigations of bacteriocin structure–function relationships, genetic organization, and their ecological role and evolutionary history. Colicin expression is often dependent on host regulatory pathways (such as the SOS system), is usually confined to times of stress, and results in death of the producing cells. This study investigates the role of the SOS system in mediating this unique form of toxin expression. A comparison of all the sequenced enteric bacteriocin promoters reveals …
A New Genetic Locus In Sinorhizobium Meliloti Is Involved In Stachydrine Utilization, Donald A. Phillips Dr., Eve S. Sandee Dr., Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Daniel Lerudulier Dr., Cecillia M. Joseph Dr.
A New Genetic Locus In Sinorhizobium Meliloti Is Involved In Stachydrine Utilization, Donald A. Phillips Dr., Eve S. Sandee Dr., Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Daniel Lerudulier Dr., Cecillia M. Joseph Dr.
Jan A.C. Vriezen Dr.
Stachydrine, a betaine released by germinating alfalfa seeds, functions as an inducer of nodulation genes, a catabolite, and an osmoprotectant in Sinorhizobium meliloti. Two stachydrine-inducible genes were found in S. meliloti 1021 by mutation with a Tn5-luxAB promoter probe. Both mutant strains (S10 and S11) formed effec- tive alfalfa root nodules, but neither grew on stachydrine as the sole carbon and nitrogen source. When grown in the absence or presence of salt stress, S10 and S11 took up [14C]stachydrine as well as wild-type cells did, but neither used stachydrine effectively as an osmoprotectant. In the absence of salt stress, both …