A successful symbiotic relationship between Sinorhizobium meliloti and its host Medicago sativa (alfalfa) depends on several signaling mechanisms, such as the biosynthesis of exopolysaccharides (EPS) by S. meliloti. Previous work in our laboratory has shown that a quorum-sensing mechanism controls the production of the symbiotically active EPS II. Recent microarray analysis of the whole-genome ...

The ability of F-like plasmids to promote transfer from the F origin of transfer was determined. Chromosome transfer was measured from plasmid derivatives of RecA(-) Hfr deletion strains which had lost all the F transfer genes but which in some cases retained, and in others had also lost, the origin sequence. ColV2 and ColVBtrp could initiate transfer from the F origin, but R100-1, R1-19, and R...

Background Cholera is a severe dehydrating illness of humans caused by toxigenic strains of Vibrio cholerae O1 or O139. Identification of immunogenic V. cholerae antigens could lead to a better understanding of protective immunity in human cholera. Methods We probed microarrays containing 3652 V. cholerae antigens with plasma and antibody-in-lymphocyte supernatant (ALS, a surrogate marker of ...

Response to changes in light conditions involves a variety of receptors that can modulate gene expression, enzyme activity and/or motility. For the study of light-regulated effects of Agrobacterium tumefaciens, we used a global analysis approach - proteomics - and compared the protein patterns of dark- and light-grown bacteria. These analyses revealed a significant reduction of FlaA and FlaB - ...

Pseudostatic analysis is one of the simplest approaches used in earthquake engineering to analyze the seismic response of soil embankments and slopes. However, the choice of seismic coefficients used in the analysis can be arbitrary and generally lacks rationale. To investigate this, a parametric study was performed on a soil embankment of varied geometric characteristics and soil properties su...

In order to verify the applicability of computer numerical simulation method under complex engineering conditions, and solve problem that it is difficult guarantee normal construction underground projects with a depth more than 1 km (it carry out multiple field attempts high-depth if you simply use ordinary calculation method, its accuracy guarantee). For geological conditions an mine 1300 m in...