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Desiccation Induces Viable But Non-Culturable Cells In Sinorhizobium Meliloti 1021, Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Klaus R. Nusslein Dr.
Desiccation Induces Viable But Non-Culturable Cells In Sinorhizobium Meliloti 1021, Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Klaus R. Nusslein Dr.
Jan A.C. Vriezen Dr.
Sinorhizobium meliloti is a microorganism commercially used in the production of e.g. Medicago sativa seed inocula. Many inocula are powder-based and production includes a drying step. Although S. meliloti survives drying well, the quality of the inocula is reduced during this process. In this study we determined survival during desiccation of the commercial strains 102F84 and 102F85 as well as the model strain USDA1021. The survival of S. meliloti 1021 was estimated during nine weeks at 22% relative humidity. We found that after an initial rapid decline of colony forming units, the decline slowed to a steady 10-fold reduction in …
Diversity Of Oligotrichia And Choreotrichia Ciliates In Coastal Marine Sediments And In Overlying Plankton, Jan A.C. Vriezen Dr., Mary Doherty Dr., Maiko Tamura Dr., George B. Mcmanus Dr.
Diversity Of Oligotrichia And Choreotrichia Ciliates In Coastal Marine Sediments And In Overlying Plankton, Jan A.C. Vriezen Dr., Mary Doherty Dr., Maiko Tamura Dr., George B. Mcmanus Dr.
Jan A.C. Vriezen Dr.
Elucidating the relationship between ciliate communities in the benthos and the plankton is critical to understanding ciliate diversity in marine systems. Although data for many lineages are sparse, at least some members of the dominant marine ciliate clades Oligotrichia and Choreotrichia can be found in both plankton and benthos, in the latter either as cysts or active forms. In this study, we developed a molecular approach to address the relationship between the diversity of ciliates in the plankton and those of the underlying benthos in the same locations. Samples from plankton and sediments were compared across three sites along the …
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 …
Responses Of Rhizobia To Desiccation In Relation To Osmotic Stress, Oxygen, And Temperature, Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Klaus R. Nusslein Dr.
Responses Of Rhizobia To Desiccation In Relation To Osmotic Stress, Oxygen, And Temperature, Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Klaus R. Nusslein Dr.
Jan A.C. Vriezen Dr.
No abstract provided.
Desiccation Responses And Survival Of Sinorhizobium Meliloti Usda 1021 In Relation To Growth Phase, Temperature, Chloride And Sulfate Availability, Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Klaus R. Nusslein Dr.
Desiccation Responses And Survival Of Sinorhizobium Meliloti Usda 1021 In Relation To Growth Phase, Temperature, Chloride And Sulfate Availability, Jan A.C. Vriezen Dr., Frans J. Debruijn Dr., Klaus R. Nusslein Dr.
Jan A.C. Vriezen Dr.
Aims: To identify physical and physiological conditions that affect the survival of Sinorhizobium meliloti USDA 1021 during desiccation. Methods and Results: An assay was developed to study desiccation response of S. meliloti USDA 1021 over a range of environmental conditions. We deter- mined the survival during desiccation in relation to (i) matrices and media, (ii) growth phase, (iii) temperature, and (iv) chloride and sulfate availability. Conclusions: This study indicates that survival of S. meliloti USDA 1021 during desiccation is enhanced: (i) when cells were dried in the stationary phase, (ii) with increasing drying temperature at an optimum of 37°C, and …
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 …