Induced defence responses of contrasting bread wheat genotypes under differential salt stress imposition.

Plants, being sessile in nature, have developed mechanisms to cope with high salt concentrations in the soil. In this study, the effects of NaCl (50-200 mM) on expression of high-affinity potassium transporters (HKTs), antioxidant enzymes and their isozyme profiles were investigated in two contrasting bread wheat (Triticum aestivum L.) genotypes viz., HD2329 (salt-sensitive) and Kharchia65 (salt-tolerant). Kharchia65 can successfully grow in salt affected soils, while HD2329 cannot tolerate salt stress. Differential expression studies of two HKT genes (TaHKT2;1.1 and TaHKT2;3.1) revealed their up-regulated expression (~1.5-fold) in the salt-sensitive HD2329 and down-regulated (~5-fold) inducible expression in the salt-tolerant genotype (Kharchia65). Specific activity of antioxidant enzymes, viz. superoxide dismutase (SOD), peroxidase (POX), ascorbate peroxidase (APX), catalase (CAT) and glutathione reductase (GR) was found to be higher in the salt-tolerant genotype. Isozyme profile of two (POX and GR) antioxidant enzymes showed polymorphism between salt-tolerant and salt-sensitive genotypes. A new gene TaHKT2;3.1 was also identified and its expression profile and role in salt stress tolerance in wheat was also studied. Partial sequences of the TaHKT2;1.1 and TaHKT2;3.1 genes from bread wheat were submitted to the EMBL GenBank database. Our findings indicated that defence responses to salt stress were induced differentially in contrasting bread wheat genotypes which provide evidences for functional correlation between salt stress tolerance and differential biochemical and molecular expression patterns in bread wheat.

A study on plasma selenium level among pregnant women at Rohtak, Haryana.

Selenium is an important trace element for human health. Selenium levels in mothers may have significant effects on fetal and neonatal nutrition. In a cross-sectional study undertaken in Rohtak, Haryana, plasma selenium level in mothers was investigated at the time of delivery. The mean plasma selenium level in full term mothers (n=82) was 70.63 +/- 1.62 ppb and in preterm mothers (n = 58), it was 63.28 +/- 2.31 ppb. The difference was statistically significant (p < 0.05). These levels were, however, below the reported normal level of 75-120 ppb in adults. Rura/urban stay, parity, maternal age, socio-economic and literacy status etc. did not influence the selenium level of mothers in either of the groups.

Selenium in the neonate.

Selenium is a trace element of tremendous importance in human health. It is a constituent of the antioxidant enzyme. Glutathione peroxidase and therefore is vital to antioxidant defense. Several diseases of the neonate have been shown to be caused at least in part by oxygen free radicals. These include bronchopulmonary dysplasia retinopathy of prematurity necrotising enterocolitis patient ductus arteriosus and neuronal injury of hypoxic ischemic encephalopathy. Good selenium nutrition is therefore of key importance to antioxidant defense in the neonate. The communique reviews the important role that selenium might play in neonatal health & disease.

Maternal and cord plasma selenium levels in full-term neonates.

Selenium is a part of the enzyme glutathione peroxidase and has an important role in the prevention of oxygen free radical injury. Hence good selenium nutrition is of special relevance to the neonate. The present study evaluated plasma selenium levels in cord plasma of 82 full term, appropriate for gestational age babies and their mothers at delivery. The plasma selenium levels in babies were 54.17 +/- 1.34 ppb which was significantly lower than 70.63 +/- 1.62 ppb seen in their mothers. Anemic mothers with a Hb < 8 g/dl had a plasma selenium level (60.74 +/- 4.57 ppb) which was lower than those with a Hb > 8 g/dl i.e. 74.19 +/- 2.17 ppb. Maternal age, parity, literacy and socio-economic status did not affect the plasma selenium levels.