In studies of dynamic changes in cellular structure and metabolism and the experimental modification of these properties during various stages of the cell cycle, it is often desirable to determine periodically the synthesis of macromolecules in the cell. In this paper we present a simplified method for determining the rates and total amount of DNA synthesis and R N A synthesis in synchronized h...

Studies have been carried out on the glycosphingolipids of human KB cells grown in monolayer and suspension culture, and by synchronization of the latter with a double thymidine (2mM) block. Glycosphingolipids were identified tentatively by thin layer chromatography, gas-liquid chromatography, and combined gas-liquid chromatography and mass spectrometry. The predominant gangliosides in the thes...

The cholinergic mouse neuroblastoma cell line NS20Y was adapted to undifferentiated growth in suspension culture. When suspension cells were transferred to surface culture and treated with dibutyryl cyclic AMP, the cells underwent differentiation as assessed by biochemical, morphological, and physiological criteria. Differentiated NS20Y cells in co-culture with mouse muscle cells had the capaci...

A phytostat to mass culture higher plant cells in liquid medium is described. This apparatus allowed the culture in batch, turbidostat and chemostat of 20 liters of cells. Automatic control of cell suspension growth was based on culture turbidity. Changes with time of certain cell characteristics, particularly cell respiration and phospholipid content, indicated that the test time to harvest la...

Procedures are described for the isolation of conditional lethal mutants of mouse L-60T cells. The mutant lines were temperature sensitive by the following criteria: (a) colony-forming ability, (b) growth in suspension culture, and (c) rate of uptake of tritiated-thymidine.