Genetic Study of Human Cells in Vitro

Abstract

The isolation of carbohydrate variants from cultures of HeLa and conjunctival cells was described. Factors inherent in the cell culture system, such as parent populations and dialyzed serums, have been shown to influence the outcome of variant isolations. Established stable variants incorporated significantly more pentoses or lactate into various cell fractions than the parent cultures. Besides their abilities to propagate continuously in the selecting environments, the variants multiplied slower, were more susceptible to sub-zero preservation and the cytotoxic effect of D-2-deoxyglucose, showed lower cloning efficiencies and were less susceptible to the deleterious effect of glucose oxidase. The ribose variants also differed from the parent cultures in morphological appearance such as formation of multinucleated cells and ring-shaped colonies. They converted more ribose into other component sugars of mucopolysaccharides than the parent cultures. Preliminary analyses of the mucopolysaccharides extracted from the ribose variants and parent cultures showed large difference in their carbohydrate (Molisch-positive materials) and DNA ratios. Evidence suggests that a sequence of interrelated events from genetic selection to primitive morphogenesis has been established.

Positron emission tomography probe demonstrates a striking concentration of ribose salvage in the liver

“…Fasting blood ribose concentrations are ∼50-fold lower than blood glucose concentrations (3). With few exceptions, cells and tissues cannot survive with ribose as their sole carbohydrate source (10)(11)(12). Additionally, RBKS is substrate-inhibited at ribose concentrations of >0.5 mM, suggesting that cells may limit the amount of ribose they salvage (6).…”

6‐Deoxy‐D‐glucose and D‐xylose: Analogs for the study of D‐glucose transport by mouse 3T3 cells

“…These findings are consistent with the report of Eagle et al (1958) that D-xylose was among a group of sugars that permitted only slight initial growth of human cell cultures; it was concluded that this partial effect could have been due to contamination with other active sugars. Chang (1960) reported that most cultures of human conjunctival cells and HeLa cells underwent degeneration when cultured in the presence of D-xylose as sole sugar source, but that occasional cultures yielded variants that were capable of growth on D-xylose over several transfers. These variants incorporated significantly more [14C]D-xylose into cellular material than did parent cultures, which incorporated little or no isotopic xylose.…”

A Comparative Study of the Growth, Nutrition, and Metabolism of the Primary and the Transformed Human Cells in Vitro

“…Such differences cannot be attributed entirely to a better regulation of available glucose in the primary amnion cell since, when lactate is supplied, the conversion to COs occurs also at a much lower level. The ability of the transformed cells to utilize ribose and xylose and the existence of mutants capable of continuous multiplication with these pentoses as the sole carbohydrate source is well established (23). It is interesting that such dormant cells as the amnion also utilized ribose and xylose.…”

“…from the primary explants, these cells are subsequently referred to as the transformed cells. The preservation and propagation of stock cultures of the transformed cells have already been described (23).…”