Search PubMed⌕ Search

Biomedical subjects

S Steiner

Publications and source records attributed to S Steiner.

At least 91 records · Page 5Linked to original sources
PubMed1976

Fucolipid metabolism as a function of cell population density in normal and murine sarcoma virus-transformed rat cells.

The incorporation of isotopically labeled fucose into the lipids of normal and murine sarcoma virus-transformed rat cells as a function of cell population density was examined. When normal cells were seeded at low cell density, the levels of the major fucolipids, i.e., fucolipids III and IV, were substantially reduced, but then they increased as the cells approached confluency. This variation in synthesis of fucolipids III and IV appeared to be primarily related to cell density and not to cell growth. Chase experiments revealed that the reduced level of fucolipids III and IV in sparse normal cells is due to decreased synthesis rather than to increased catabolism. In contrast to the observations with normal rat cells, the high level of fucolipid III and the low level of fucolipid IV in murine sarcoma virus-transformed rat cells was shown to be independent of cell population density.

Animals↗
PubMed1976

Factors involved in concanavalin A agglutination of KB and NC37 cells grown in suspension culture.

NC37 and KB cells grown in suspension culture remained agglutinable at 23 degrees C by concanavalin A (Con A) after sufficient glutaraldehyde fixation to prevent lateral mobility (clustering) of Con A binding sites. In contrast, at 4 degrees C agglutination of the fixed cells was blocked. No significant differences in 3H-Con A binding were observed between unfixed cells and glutaraldehyde-fixed cells at 23 degrees C and unfixed cells at 4 degrees C. Con A bound to fixed cells at 4 degrees C produced agglutination when the cells were washed and then warmed to 23 degrees C. Thus a cold-sensitive factor unrelated to the binding of Con A or the clustering of Con A sites is necessary for agglutination to occur.

Binding Sites↗
PubMed1976

Altered microfilament structure in cells transformed with a temperature-sensitive transformation mutant of murine sarcoma virus.

The structure and distribution of microfilaments were examined by electron microscopy in uninfected normal rat kidney (NRK) cells, murine sarcoma virus (MSV)-transformed NRK cells, and NRK cells infected with a cold-sensitive transformation mutant of MSV, i.e., NRK (MSV-1b) cells, grown at both permissive (39 degrees) and nonpermissive (33 degrees) temperature. The uninfected cells contained numerous microfilaments which were especially prominent at sites of intercellular adherens junctions. In contrast, the MSV-transformed cells contained few microfilaments and did not form adherens junctions. At 33 degrees, the NRK (MSV-1b) cells appeared normal but formed an altered form of adherens junction with disorganized microfilaments. At 39 degrees, these cells resembled NRK cells transformed by wild-type MSV but still formed a few of the altered type of adherens junctions. Disorganized adherens junction microfilaments were also found in cells newly infected with wild-type MSV. These results suggest that the perturbed assembly of microfilaments at adherens junctions may be an intermediate stage in the loss of adherens junctions during viral transformation.

Cell Line↗
PubMed1975

1-H and 13-C nuclear magnetic resonance spectra of the lipids in normal and SV 40 virus-transformed hamster embryo fibroblast membranes.

Well resolved 1-H and 13-C NMR spectra were obtained with normal and SV 40-transformed cell membranes. Estimation of the ratio of 13-CT2 values of the normal to transformed cell membranes showed an increased intermolecular motion in the transformed cell membranes. The temperature dependence of the (CH2) line in the 1-H spectra in the temperature range 298-343 degrees K shows an activation energy for the lateral diffusion of the fluid phospholipid regions in the normal cell membranes while the transformed ones show practically no temperature dependence in this temperature range. The fluidity of the phospholipid region in the transformed cell membrane seems to be significantly higher than that observed in the normal cell material. These data support and extend the findings concerning the mobility of the concanavalin A binding/agglutinating sites on the surface of normal and virus-transformed cells and suggest further approaches to the study of the membrane alterations in tumor cells.

Animals↗
PubMed1974

Major polar lipids of hepatitis B antigen preparations: evidence for the presence of a glycosphingolipid.

The major phospholipids of hepatitis B antigen, subtype adw, were characterized as phosphatidylcholine, sphingomyelin, and lysophosphatidylcholine. In addition, two carbohydrate-containing lipids were observed, one of which was characterized as a non-sialic acid-containing, water-soluble glycosphingolipid. Upon hydrolysis the glycosphingolipid yielded both hydroxy and non-hydroxy fatty acid as well as a long-chain base which was putatively identified as dihydrosphingosine.

Chromatography, Paper↗
PubMed1974

Inhibition of cardiolipin synthesis following infection with herpes simplex virus.

The results of this study show that the synthesis of the inner mitochondrial membrane phospholipid, cardiolipin, is markedly inhibited following infection of human embryonic lung or hamster embryo fibroblast cells with herpes simplex virus type 1 or 2. The synthesis of other phospholipids, i.e., phosphatidylcholine, phosphatidylethanolamine, sphingomyelin, and phosphatidylinositol, is relatively unaffected.

Animals↗
PubMed1973

Occurrence of phosphonosphingolipids in Bdellovibrio bacteriovorus strain UKi2.

The major phospholipids of two strains of Bdellovibrio bacteriovorus were characterized. Both strain UKi1, which is obligately saprophytic, and strain UKi2, which is facultatively parasitic, contained phosphatidylethanolamine and phosphatidylglycerol as their major glycerophosphatides. A branched, 15-carbon fatty acid is the major component of these alkali-labile lipids. Absent from UKi1 but present in UKi2 were three alkali-stable lipids (compounds 8, 9, and 11) which appear to be phosphosphingolipids. After acid hydrolysis, both compound 8 and 9 yield the identical phosphorus-containing substance that is water soluble, dipolar ionic, and ninhydrin positive. This substance appears to contain a C-P bond since P(i) could not be released from this substance by treatment with alkaline phosphatase or by very harsh mineral acid treatment. Based on chromatographic comparisons, this phosphonate appears to be a novel lipid constituent. Upon degradation, compound 8 yields 1 mol of dihydroxy long-chain base and compound 9 yields 1 mol of a trihydroxy long-chain base. These bases appear to have a 17-carbon, possibly branched, structure based on gas-liquid chromatography retention times. Degradation of both sphingolipids yields a mixture of hydroxy fatty acids, the major component being a branched, 15-carbon hydroxy acid.

Alkaline Phosphatase↗