We have found opiate receptors enriched in two distinct subcellular fractions obtained from rat brain cellfree homogenates. By several criteria, one fraction contains synaptic plasma membranes, while the other represents predominantly smooth microsomes. Using marker enzyme analysis, we determined that the occurrence of opiate receptors in the smooth microsomal fraction cannot be attributed to ...

Suit, Joan C. (The University of Texas M. D. Anderson Hospital and Tumor Institute, Houston). Ribonucleic acid in a "membrane" fraction of Escherichia coli and its relation to cell-wall synthesis. J. Bacteriol. 84:1061-1070. 1962.-A small amount of ribonucleic acid (RNA) was found in a "membrane" fraction prepared from osmotically sensitized Escherichia coli. It exhibited an elevated metabolic ...

New methods are required for identifying membranes in subcellular fractions with respect to their origin, if such preparations are to be evaluated morphometrically. One method is freeze-fracturing which reveals intramembrane particles whose size, pattern, and numerical density differ for various membrane types. The question is examined whether the differences in numerical particle density per s...

A subcellular fraction from murine plasmacytoma cells was shown to suppress the primary antibody response when injected into normal mice. The active subcellular fraction copurified with intracisternal A-particles. The RNA extracted from subcellular fractions enriched in A-particles was also immunosuppressive. This activity was due to a population of RNA molecules that contained polyadenylic aci...

Previous attempts to relate the structure and function of hepatocytic membranes have compared biochemical data of fractions to morphological data derived from either intact tissue or fractions. The effects of the original homogenization aside, biochemical recoveries comparing membrane marker enzymes of the homogenate to subsequent fractions suggest a general conservation of activity. A sterolog...

Macromolecular markers for glial cells have been sought for a variety of reasons. One of the earliest was the need for a means of assessing the purity of cell and subcellular fractions prepared from nervous tissue. While there is still a requirement for this kind of tool, emphasis has shifted towards seeking information on biochemical differentiation among cells and their functional interaction...

Some of the kinetic properties of carnitine acetyltransferase in brain homogenates have been reported with the use of a new, sensitive radiometric method for the determination of acetylcarnitine. Those properties and the distribution pattern of carnitine acetyltransferase in various rat tissues, subcellular fractions, and discrete areas of the brain have been compared with those obtained for ch...

Whole heat-killed Mycobacterium vaccae is used as an immunotherapeutic agent in tuberculosis (TB), but the compound(s) that triggers its immunostimulatory ability is not known. Here, we show that among different subcellular fractions, the cell wall skeleton induced a prominent expression of gamma interferon in splenocytes from both non-TB and TB M. vaccae-treated mice.

Isolated human hepatocytes exhibited time-, trichloroethylene (Tri) concentration-, and cell concentration-dependent formation of S-(1, 2-dichlorovinyl)glutathione (DCVG) in incubations in sealed flasks with 25 to 10,000 ppm Tri in the headspace, corresponding to 0.011 to 4.4 mM in hepatocytes. Maximal formation of DCVG (22.5 +/- 8.3 nmol/120 min per 10(6) cells) occurred with 500 ppm Tri. Time...

Glycosylphosphatidylinositols (GPIs) are synthesized in the endoplasmic reticulum (ER) via the sequential addition of monosaccharides, fatty acid, and phosphoethanolamine(s) to phosphatidylinositol (PI). While attempting to establish a mammalian cell-free system for GPI biosynthesis, we found that the assembly of mannosylated GPI species was impaired when purified ER preparations were substitut...