BOOK REVIEW

Insect Pests of Trees and Timber in Tasmania: H. J. Elliott and D. W. deLittle. Forestry Commission, Tasmania, 1985. Pp. X + 90. $7.50.     

The HsdS polypeptide of the Type IC restriction enzyme Eco R124 is a sequence-specific DNA-binding protein

The HsdS and HsdM polypeptides of the type IC restriction enzyme EcoR124 have been purified independently and used in a set of gel retardation experiments to determine the minimum requirements for sequence-specific recognition of DNA by this enzyme. The HsdS polypeptide alone is able to bind to DNA in a sequence-specific manner. In addition, whilst the presence of the HsdM polypeptide gives rise to a stimulation of DNA binding by the HsdS subunit it is not clear whether, under the conditions of the experiments reported here, the HsdS subunit maintains the same interactions with the HsdM subunits observed in the absence of DNA.     

Alteration of the Pathogenicity of Pasteurella pneumotropica for the Murine Lung Caused by Changes in Pulmonary Antibacterial Activity

Pasteurella pneumotropica is a potential pulmonary pathogen in mice. In healthy animals, this organism was killed rapidly by the normal function of the intrapulmonary phagocytic defense mechanisms. Impairment of this bactericidal activity by the acute renal failure of nephrectomy resulted in multiplication of the Pasteurella in the lung, both when the animals were nephrectomized first and then infected, and when the animals were infected first and nephrectomized several hours after the infection. The study demonstrates that the pathogenicity of the Pasteurella organisms is governed by the functional state of these pulmonary antibacterial mechanisms.