Use of cationized ferritin as a label of negative charges on cell surfaces

Ultrastructural Demonstration of the Negative Surface Charge on Human Trophoblast

“…50 U of VCN per ml HBSS often destroyed the cell membrnae and consequently artificial adherence of ferritin particles was found, thus suggesting care is needed to insure the use of an appropriate concentration and exposure time during the VCN treatment. Cationized ferritin is an excellent method for investigating negative charges on the cell surface in that it allows labeling at physiological pH and quantitative analysis is possible (17). It was revealed in the present study that early human trophoblast bore 6 to 7 times as strong a negative charge per unit length of basal line, thus being simply calculated to have about 36 to 50 times as strong a negative charge per unit area of the cell surface as compared with the mature trophoblast.…”

The surface charge of trypanosomatids

“…Two cationic labels have been widely used: the colloidal iron hydroxide (CIH) and the cationized ferritin (CF) (Danon et al 1972, Gasic et al 1968. There are some important differences between these two labels: only pre-fixed cells can be labeled with CIH since the positive colloid was used at pH 1.8.…”

“…There are some important differences between these two labels: only pre-fixed cells can be labeled with CIH since the positive colloid was used at pH 1.8. Cationized ferritin is a derivative of native ferritin that can be used at physiological pH either in pre-fixed or even in living cells (Danon et al 1972). Treatments such as methylation and the use of neuraminidase prevent the staining by the CIH indicating that the iron micelles are bound almost exclusively to sialic acid (Gasic et al 1968).…”

Basic Surface Properties of Mononuclear Cells from Didelphis marsupialis

“…Such surface coat plays an important role in cell-cell and cell-substrate interaction processes (Cook 1986, Lamb et al 1995, Torroba et al 1995. The surface-exposed carbohydrates can be evidentiated at the ultrastructural level by using several eletrondense markers, such as rutenium red (Luft 1971) and cationized ferritin (Danon et al 1972, Grinnell et al 1976.…”

“…However, other anionic sites such as the phosphates of phospholipids and sulphates of mucopolysaccharides also contribute to the cell surface negativity, being their presence detected by diverse assays such as ultrastructural cytochemistry (Gasic et al 1968, Danon et al 1972, cell electrophoresis (Ambrose 1965, James 1979 and electrostatic interaction cromatography (Mozes & Rouxhet 1987, Rouxhet & Mozes 1990.…”