Rapid Differentiation Between Nocardia and Streptomyces by Paper Chromatography of Whole-Cell Hydrolysates

Whole-cell hydrolysates were prepared from 58 strains of nocardiae and streptomycetes. Strains morphologically intermediate between the two genera and morphological variants of the same strains were included. Paper chromatograms made from the whole-cell hydrolysates clearly demonstrated meso-diaminopimelic acid as a major constituent of cultures of Nocardia spp., and LL-diaminopimelic acid as a major constituent of cultures of Streptomyces spp. In cultures of ten strains of N. madurae and of three of N. pelletieri, meso-diaminopimelic acid predominated, thereby supporting the assignment of these species to the genus Nocardia.     

Comparison of Direct Plating Media for the Isolation and Enumeration of Enterococci in Certain Frozen Foods

A total of 15 agar media were examined for their yield, selectivity, readability, and simplicity of preparation and use. A thallium medium of Barnes was selected as the better of the high yield-fair selectivity type of medium and an azide-citrate medium of Reinbold appeared to be the better of the low yield-high selectivity type of medium. Sodium carbonate (optimal concentration, 0.20%) was found to increase recovery substantially when added to certain media, especially in the presence of 0.05% Tween 80. When these two ingredients were incorporated into a medium modified after Slanetz and Bartley, the resultant medium was superior to other media for the isolation and enumeration of enterococci in certain frozen foods, such as peas and hamburger, by the direct plating method.     

Freezing-Out Technique Applied to the Concentration of Biologically Active Materials

When applied to a dilute solution of folic acid and glucose, a freezing-out (with agitation) technique was shown to be an effective method of achieving a 20-fold reduction in volume with a loss of 10% of the active material being concentrated. Concentration of a stimulatory factor for Lactobacillus casei produced by Candida albicans in a complex medium was limited by the total solute concentration. Salts in the medium were concentrated to levels inhibitory for L. casei. The process is not selective and all solutes are concentrated.     

Electron Microscope Study of Lens Fibers

Comparative electron microscope investigations on sections of the lens cortex of the normal, mature rat, rabbit, monkey, and the normal calf reveal similar patterns of intracellular organization. The superficial lens fiber contains a nucleus, mitochondria, endoplasmic reticulum, dense granules, Golgi complex, and a quantity of small structures of low opacity which appear as filamentous and spherical configurations. Variations in number, distribution, and spatial arrangement of cytoplasmic elements in lens fibers are described. These changes in the pattern of cytoplasmic organization are concomitant with development of fibers and their displacement towards the center of the lens. Structural details of the various zones of the lens epithelium and the lens fibers are compared.     

Studies with cyanidium caldarium,an anomalously pigmented chlorophyte

Summary Cyanidium caldarium, an alga found in acid hot springs troughout the world, has a morphology and developmental history resembling those of Chlorella, but contains C-phycocyanin and no chlorophyll other than chlorophyll a. The reasons for considering it to be a member of the Chlorophyta are reviewed. Cyanidium is also remarkable for its thermal and acid tolerance. It grows readily in the dark on sugar media. However, light is required for the formation of chlorophyll and phycocyanin except in occasional variant cells which can form limited amounts of these pigments in the dark. Light-grown Cyanidium carries out normal green plant photosynthesis but resembles the red and some of the blue-green algae in that chlorophyll-absorbed light is used with lower efficiency than that absorbed by phycocyanin.The possible significance of the unusual pigmentation of Cyanidium is discussed.Contribution no.23 from the Laboratory of Comparative Physiology and Morphology of The Kaiser Foundation.     

Titration and Neutralization of Poliovirus in Micro Tissue Culture Under Increased Carbon Dioxide

Modification of the micro tissue culture technique, including incubation under increased CO(2), resulted in prolongation of the viability of the cells. As a consequence, satisfactory titrations of poliovirus and of poliovirus antiserum have been achieved by the micro method. The technique offers a number of advantages over conventional methods.     

The effect of anisotonic media upon cellular ultra-structure in fresh and fixed rat brain

Summary When tissue slices or small blocks of unfixed rat cerebrum are incubated in various anisotonic physiological media, distinctive morphological changes are induced in glial cells, neurons, and endothelial cells. The variation in observed cellular swelling and shrinkage may be related to differences in ionic content of the cytoplasm of these cells. When HAA, glutal, and osmium tetroxide fixed tissue is incubated in this manner, only the cerebrum fixed in HAA responds to osmotic inequilibrium in a manner similar to unfixed tissue. Although HAA does not fix tissues very well, the permeability of plasma membranes in the brain appears to be less altered by HAA than by glutal or osmium tetroxide. The relationship of these findings to a demonstration of the extracellular space in HAA fixed tissues is discussed.This work was supported by grants (U-1293) from the Health Research Council of the City of New York and (NB 04161-02) from the National Institute of Neurological Disease and Blindness of the National Institutes of Health.