Fear of movement/(re)injury and activity avoidance in persons with neurogenic versus vascular claudication.

Background Context: Activity avoidance and fear of movement/(re)injury are increasingly being recognized as important factors in the rehabilitation of persons suffering from chronic low back pain, yet these factors have not been thoroughly explored in persons suffering from neurogenic claudication resulting from lumbar spinal stenosis.

Purpose: To determine, compare, and explain differences in the degree of fear of movement/(re)injury and activity avoidance in persons with neurogenic claudication, vascular claudication, and asymptomatic volunteers.

Study Design: Prospective controlled cohort study at an academic medical center.

Genome sequences of three agrobacterium biovars help elucidate the evolution of multichromosome genomes in bacteria.

The family Rhizobiaceae contains plant-associated bacteria with critical roles in ecology and agriculture. Within this family, many Rhizobium and Sinorhizobium strains are nitrogen-fixing plant mutualists, while many strains designated as Agrobacterium are plant pathogens. These contrasting lifestyles are primarily dependent on the transmissible plasmids each strain harbors.

Citrate synthase mutants of Agrobacterium are attenuated in virulence and display reduced vir gene induction.

A citrate synthase (CS) deletion mutant of Agrobacterium tumefaciens C58 is highly attenuated in virulence. The identity of the mutant was initially determined from its amino acid sequence, which is 68% identical to Escherichia coli and 77% identical to Brucella melitensis. The mutant lost all CS enzymatic activity, and a cloned CS gene complemented a CS mutation in Sinorhizobium.

A new type IV secretion system promotes conjugal transfer in Agrobacterium tumefaciens.

Two DNA transfer systems encoded by the tumor-inducing (Ti) plasmid have been previously identified in Agrobacterium tumefaciens. The virB operon is required for the transfer of transferred DNA to the plant host, and the trb system encodes functions required for the conjugal transfer of the Ti plasmid between cells of Agrobacterium. Recent availability of the genome sequence of Agrobacterium allowed us to identify a third system that is most similar to the VirB type IV secretion system of Bartonella henselae.

Survival of GacS/GacA mutants of the biological control bacterium Pseudomonas aureofaciens 30-84 in the wheat rhizosphere.

GacS/GacA comprises a two-component regulatory system that controls the expression of secondary metabolites required for the control of plant diseases in many pseudomonads. High mutation frequencies of gacS and gacA have been observed in liquid culture. We examined whether gacS/gacA mutants could competitively displace the wild-type populations on roots and thus pose a threat to the efficacy of biological control.