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.     

Stuttering—The Effect of Treatment with D-Amphetamine and a Tranquilizing Agent,Trifluoperazine; A Preliminary Report on an Uncontrolled Study

In an institution for the mentally retarded, an uncontrolled study was made on the effects of d-amphetamine, d-amphetamine followed by trifluoperazine, and of combined d-amphetamine and trifluoperazine on stuttering. Of 28 patients to whom d-amphetamine was given, 14 showed improvement after one month''s treatment. Eight more showed improvement when trifluoperazine was given for one month to those who did not improve on d-amphetamine. In many cases, improvement was sustained at least six months after treatment was discontinued.Treatment with d-amphetamine was apparently more effective in patients with functional than with organic retardation.     

Patterns of segregation of structural elements during cell division

Summary Adaptations of currently available autoradiographic electron microscopic methods to the study of organelle development in single Paramecium cells are described. Cells of known age were pulse-labeled with tritiated leucine and observed either as whole mounts, or as sections of specified age and cell-lineage. Labeled trichocysts appear as early as one hour after uptake and retain the label without dilution for at least 3 fission generations thereafter. Cells grown in unlabeled medium, but derived from labeled cells, show the bulk of the residual label to be conservatively associated with the stable structural organelles of the cell surface. These organelles include those trichocysts and ciliary corpuscles that had been synthesized in the ancestral progenitor cell during or shortly after administration of the isotopically labeled amino acid.Work supported by U. S. Atomic Energy Commission.Dedicated to Professor Friedrich Wassermann with admiration and affection on the occassion of his eightieth birthday.