Carbohydrate content and antioxidative potential of the seed of three edible indica rice (Oryza sativa L.) cultivars.

Rice (Oryza sativa L.) grains or seeds are known to lose much of their nutrient and antioxidant contents, following polishing. The current study was undertaken to evaluate and compare the carbohydrate content and antioxidant parameters in the unpolished and polished seeds of three edible indica rice cultivars, namely Swarna (SW), the most popular indica rice cultivar in India and aromatic or scented cultivars Gobindobhog (GB) and Pusa Basmati (PB). While both the sucrose and starch content was the maximum in PB seeds (both unpolished and polished), the amylose content was the highest in SW polished seeds. SW polished seeds were superior as compared to GB and PB cultivars in terms of total antioxidant capacity, DPPH radical scavenging and Fe(II) chelation potential, as well as the highest lipoxygenase (LOX) inhibition or H2O2 scavenging potential, probably due to the maximum accumulation of total phenolics and flavonoids, the two important antioxidants. The reducing power ability was, however, identical in both SW and GB polished seeds. The PB polished seeds were more potent in superoxide and hydroxyl scavenging, whereas GB in nitric oxide (NO) scavenging. The common observation noted after polishing of seeds was the reduction in the level of carbohydrates and antioxidant potential, though the extent of reduction varied in the three cultivars. The only exception was GB, where there was no alteration in NO scavenging potential even after polishing. Our study showed the better performance of SW polished seeds with respect to higher amylose content and majority of the tested parameters governing antioxidant capacity and radical scavenging potential, thus highlighting the greater dietary significance of SW over the other two cultivars.

Analysis of comparative efficiencies of different transformation methods of E. coli using two common plasmid vectors.

The efficiencies of different transformation methods of E. coli DH5α strain, induced by several cations like Mg2+, Mn2+, Rb+ and especially Ca2+, with or without polyethylene glycol (PEG) and dimethyl sulfoxide (DMSO) were compared using the two commonly used plasmid vectors pCAMBIA1201 and pBI121. The widely used calcium chloride (CaCl2) method appeared to be the most efficient procedure, while rubidium chloride (RbCl) method was the least effective. The improvements in the classical CaCl2 method were found to further augment the transformation efficiency (TR)E for both the vectors like repeated alternate cycles of heat shock, followed by immediate cold, at least up to the third cycle; replacement of the heat shock step by a single microwave pulse and even more by double microwave treatment and administration of combined heat shock-microwave treatments. The pre-treatment of CaCl2-competent cells with 5% (v/v) ethanol, accompanied by single heat shock also triggered the (TR)E, which was further enhanced, when combined heat shock-microwave was applied. The minor alterations or improved approaches in CaCl2 method suggested in the present study may thus find use in more efficient E. coli transformation.