Plasmid transformation of Bacillus sphaericus 1593

Plasmids pUB110 and pBC16 were introduced by protoplast transformation into the entomocidal bacterium Bacillus sphaericus 1593. Transformants expressed the antibiotic resistance determinants present on the plasmid and exhibited sporulation frequencies and larvicidal toxicities which were equivalent to those characteristic of the parent strain. These transformations constitute the first report of genetic transfer in B. sphaericus.     

Quantitative fluorometric analysis of plant and microbial chitosanases.

A quantitative fluorometric assay for chitosanase activity in bacterial and plant tissues was developed. The assay can be conducted with either finely milled preparations of chitosan in suspension or dissolved chitosan; activity is based on measurements of glucosamine (GlcN) or oligomers of GlcN. GlcN is detected fluorometrically after reaction with fluorescamine with detection in the nanomole range. Fluorescence measurements of chitosanase activity and radioassay of chitinase in commercial preparations of chitinase from Streptomyces griseus revealed that both activities were present. Specific activities for the S. griseus chitosanase using suspended and soluble chitosans were respectively 1.24 and 6.4 mumol GlcN.min-1.mg protein-1. Specific activity of the S. griseus chitinase was 0.98 mumol GlcN.min-1.mg protein-1. Sweet orange callus tissue was tested for chitosanase and chitinase activity. It was necessary to remove small amine-containing molecules from the callus preparations before chitosanase activity could be assayed. The specific activity for chitinase and chitosanase in desalted extracts of nonembryogenic Valencia sweet orange callus tissue was determined to be 18.6 and 89.4 nmol GlcN.min-1.mg protein-1, respectively.     

The importance of oedema in acute radiation injury to the cerebral cortex of rats: An electron microscope study

Summary The oedematous changes in the cerebral cortex of rats after acute irradiation are described. The importance of these changes in the over-all injury is discussed. Swelling and rupture of clear glial cells without expansion of the extracellular space are seen during the early phases of injury. Not all of the clear glia become swollen, but those that do eventually undergo complete dissolution, initiating small foci of severe damage. The necrosis that ultimately encompasses the entire irradiated field may spread from these initial sites of injury. Clear glial cells that do not undergo swelling show an unusual type of reaction before they become necrotic.This work was supported by the U.S. Atomic Energy Commission and formed a part of a dissertation submitted in partial fulfillment for the degree of Doctor of Philosophy to the faculty of the Graduate School of Loyola University, Chicago, Illinois.The author wishes to express his indebtedness to Dr. F. Wassermann of Argonne National Laboratory, and Dr. D. S. Jones of Stritch School of Medicine, Loyola University, for their advice and guidance during the course of this study.Dedicated to Professor Friedrich Wassermann with admiration and affection on the occasion of his 80th birthday.