Binding of Salmonella minnesota R-form glycolipid mR595 to rat fibroblasts and its effect on cell metabolism and cell behaviour

Trypsinized normal rat embryo fibroblasts and untrypsinized and trypsinized transformed rat fibroblasts have two orders of binding sites for bacterial glycolipid mR595. The high order sites fix 1–3 μg glycolipid mR595/10⁵ cells and those of the low order fix about 6 μg glycolipid mR595/10⁶ cells. Ca⁺⁺ is required for the low order glycolipid mR595 binding to be trypsinized but not to the untrypsinized transformed rat fibroblasts. The low order binding but not to the untrypsinized transformed rat fibroblasts. The low order binding is temperature dependent with the transition temperature lying between 25 and 37°C. Exogenously added ganglioside and glycoproteins contained in the fetal calf serum do not inhibit fixation of glycolipid mR595. Only β-lipoprotein at high concentrations is slightly inhibitory. Glycolipid mR595 fixation to transformed fibroblast does not alter their morphology and appears to slightly improve cell attachment to substratum. Glycolipid mR595 fixation results in a lengthening of the S-phase of the cell cycle and a reduction in 2-deoxyglucose uptake. Uptake of inorganic phosphate is not affected. Inhibition of phospholipid synthesis is observed in mR595 fixed fibroblasts whereas synthesis of cell surface glycoproteins and the content of cellular gangliosides is not affected.