Elizabeth M. Tucker

The identification of ornithine and lysine at high concentrations in the red cells of sheep with an inherited deficiency of glutathione

Abstract Red cells from Finnish Landrace sheep with an inherited deficiency of reduced glutathione were found to contain high concentrations of ornithine (5.3 ± 0.8 mmoles/l packed cells) and lysine (7.8 ± 1.0 mmoles/l packed cells), in contrast to red cells from normal individuals where the concentrations were 0.20 ± 0.08, and 0.28 ± 0.11 mmole/l packed cells, respectively. Red cells from Merino sheep with low glutathione levels showed no significant concentrations of these amino acids.

Haemolysis of normal and glutathione-deficient sheep erythrocytes by selenite and tellurite

Abstract Both selenite and tellurite caused lysis of normal sheep erythrocytes in vitro . GSH-deficient sheep erythrocytes were considerably more resistant to haemolysis than normal cells. This effect was independent of the biochemical lesion responsible for GSH-deficiency (amino acid transport lesion or γ-glutamyl cysteine synthetase deficiency). These and other observations directly implicate intracellular GSH in the lytic mechanism. Selenite and tellurite-induced haemolysis therefore provides a simple method for detecting GSH-deficient cells. The lytic effect of selenite may explain some of the symptoms associated with selenium poisoning.

Active potassium transport and the L and M antigens of sheep and coat red cells

Abstract 1. 1. Active K + transport and the distribution of the L and M antigens have been investigated in sheep and goat red cells. 2. 2. Low K − (LK) type goat red cells have a significantly lower rate of active K + uptake than high K + (HK) type cells. Active K + transport and the associated (Na + - K + -activated ATPase activity in LK goat red cells was stimulated 1.5-8-fold by sensitization with sheep anti-L, even though the presence of this antibody could not be detected by complement lysis. 3. 3. Ether and acid eluates of anti-L from sensitized goat and sheep red cells haemolysed sheep but not goat red cells and stimulated active K + transport in both goat and sheep red cells. There was no apparent correlation between the presence of the M antigen and K + types in goats as there is in sheep. 4. 4. It is suggested that there may be two specificities of L substance, one associated specifically with the K + pump in sheep and goat red cells and not readily detectable serologically, and the other, found only on sheep red cells which may or may not be associated with the pump but which is easily detected by haemolytic tests.

Relationship between cell age, glutathione and cation concentrations in sheep erythrocytes with a normal and defective transport system for amino acids

Percoll density gradients were used to separate sheep erythrocytes according to cell age. Erythrocytes with low intracellular levels of glutathione (GSH) caused by an inherited deficiency of the System C amino acid transporter exhibited large age-related decreases in GSH and K+ content. In contrast, there was no age-related loss of intracellular GSH in normal sheep erythrocytes or in sheep erythrocytes with low GSH resulting from a diminished activity of gamma-glutamylcysteine synthetase. Loss of GSH from amino acid transport-deficient erythrocytes was paralleled by the progressive appearance of Heinz bodies in the cells, indicating an increased susceptibility to oxidative damage.

Identification of a 25 kDa polypeptide associated with the L antigen in low potassium-type sheep red cells

Antisera to the L blood group antigen have been used, following radioiodination of low potassium-type sheep red cells and subsequent immunoprecipitation, to identify a polypeptide of the L antigen. Only LK, and not HK, cells express this 25 kDa component which is present in very low copy number.

The solubilization of the L and M antigens from sheep red cell membranes

The Lp, L1 and M antigens from sheep red cells were solubilized using the non-ionic detergent Triton X-100 in the presence of dithiothreitol. Recovery rates were improved when membranes were sonicated at 4 degrees C in the presence of the detergent; values in the range 16-25% (M) and 9-17% (Lp and L1) were achieved for recovery.

Amino acid transport properties of erythrocytes from normal newborn lambs and lambs with an inherited defect in amino acid transport.

An amino acid transport defect which occurs in the erythrocytes of adult sheep is also present in foetal erythrocytes from newborn lambs which have inherited the lesion. The transport defect in erythrocytes from adult sheep is associated with high intracellular levels of ornithine and lysine and a markedly diminished GSH concentration. Although the lesion in foetal cells also results in the accumulation of ornithine and lysine, the intracellular GSH concentration is only moderately diminished.