ABSTRACT
A twelve-year-old neutered male beagle presented for a cranial abdominal mass. The results of physical examination, laboratory tests, radiography, and ultrasonography are presented. A torsion of the quadrate lobe of the liver was diagnosed at surgery and confirmed by histopathology. A brief discussion of liver lobe torsion is presented.
Subject(s)
Dog Diseases/diagnostic imaging , Liver Diseases/veterinary , Animals , Dog Diseases/physiopathology , Dogs , Liver Diseases/diagnostic imaging , Male , Radiography , Torsion Abnormality/diagnostic imaging , Torsion Abnormality/veterinary , UltrasonographyABSTRACT
The StpA protein is closely related to H-NS, the well-characterised global regulator of gene expression which is a major component of eubacterial chromatin. Despite sharing a very high degree of sequence identify and having biochemical properties in common with H-NS, the physiological function of StpA remains unknown. We show that StpA exhibits similar DNA-binding activities to H-NS. Although both display a strong preference for binding to curved DNA, StpA binds DNA with a four-fold higher affinity than H-NS, with K(d)s of 0.7 microM and 2.8 microM, respectively. It has previously been reported that expression of stpA is derepressed in an hns mutant. We have quantified the amount of StpA protein produced under this condition and find it to be only one-tenth the level of H-NS protein in wild-type cells. Our findings explain why the presence of StpA does not compensate for the lack of H-NS in an hns mutant, and why the characteristic pleiotropic hns mutant phenotype is observed.
