Addition Of Sodium Selenite Research Articles

Effects of selenite, CO 2 and illumination on the induction of selenium-dependent glutathione peroxidase in Chlamydomonas reinhardtii

When sodium selenite was added to Chlamydomonas reinhardtii cells grown in the absence of sodium selenite under illumination (10 000 lux) and ordinary air (0.03% CO 2 concentration), glutathione peroxidase activity increased to a peak after 24 h, and ascorbate peroxidase activity concomitantly disappeared after 6 h. The effect of cycloheximide and the immunochemical titration with antibody directed against bovine erythrocyte glutathione peroxidase showed that the increase in glutathione peroxidase activity was due to protein synthesis. Transfer of Chlamydomonas cells either from low CO 2 concentration (ordinary air: 0.03% CO 2) to high CO 2 concentration (5% CO 2) or from light to dark together with the addition of sodium selenite stopped the increase in the glutathione peroxidase activity. The effect of illumination was saturated at a light intensity of about 6000 lux. The results reported here indicate that low CO 2 concentration in the atmosphere and illumination are required for the induction of glutathione peroxidase, and suggest that selenium-induced glutathione peroxidase as well as catalase can play an important role in the scavenging of H 2O 2 generated in pseudocyclic electron transport of Chlamydomonas chloroplasts.

Ascorbate interacts with sodium selenite to increase glutathione peroxidase activity in selenium-deficient chick duodena cultured in vitro

Duodena from Selenium (Se)/vitamin E-depleted 19 d chick embryos were cultured in vitro for 0-30 h. The addition of sodium selenite to the culture medium was associated with increased selenium-dependent glutathione peroxidase (SeGSHpx) activity after 24 h of incubation. In the absence of Se or in the presence of sodium ascorbate supplementation alone, SeGSHpx activity showed a gradual decline over the same time period. When ascorbate was added, along with sodium selenite, SeGSHpx activity was increased earlier and to a greater extent than in the presence of Se alone. These observations show that ascorbate can influence the metabolism of sodium selenite, resulting in increased SeGSHpx activity.

Protective effect of trace elements other than selenium against dietary necrotic liver degeneration.

RATS fed on diets containing certain yeasts as their sole source of protein develop a dietary necrotic liver degeneration, leading to early and rapid death. Necrogenic diets are deficient in three factors, vitamin E1, cystine2 and a ‘Factor 3’3, each of which will alone prevent the manifestations of disease. Potent Factor 3 concentrates have been prepared from casein hydrolysates4 and, recently, Schwarz and Foltz5 have shown that similar concentrates prepared from kidney powder hydrolysates contain selenium in bound form. Addition of sodium selenite to rat diets (to supply 4 µgm. of selenium per 100 gm. of diet) gave complete protection against death from liver necrosis during the experimental period of thirty days, indicating that selenium might be part of Factor 3. Schwarz and Foltz have inferred that “selenium is an essential trace element”.