In vitro propagation of wild yams, Dioscorea oppositifolia (Linn) and Dioscorea pentaphylla (Linn)

In vitro propagation of two wild yams, Dioscorea oppositifolia and Dioscorea pentaphylla, is reported. Multiple shoots were initiated from nodal explants on Murashige and Skoog (MS) medium supplemented with 8.8 ìM 6-benzylaminopurine (BAP) and 0.3% (w/v) activated charcoal. Root induction was also achieved simultaneously from the base of the shoots in the same medium. Individual shoots with a minimum of one node were excised and rooted in vitro on MS medium with 2.67 ìM -naphthaleneacetic acid (NAA) or ex vitro rooted on by treatment with 49 ìM indole-3-butyric acid (IBA) for 30 min. Regenerants acclimatized in soil-rite showed vigorous shoot growth (within 2 weeks) and after 5 - 6 months were suitable for planting. Plantlets also developed tubers on MS medium with 8.8 ìM 6-benzylaminopurine (BAP)

Evaluation of phytonutrients and vitamin contents in a wild yam, Dioscorea belophylla (Prain) Haines

The species studied was found to contain bioactive compounds comprising saponins (18.46 mg 100-1g), alkaloids (0.68 mg 100-1 g), flavonoids (8.84 mg 100-1 g), tannins (4.2 x102 mg 100-1 g) and phenols (2.8x103 mg 100-1 g). This yam contained vitamins such as ascorbic acid, riboflavin and thiamin. The importance of these chemical constituents is discussed with respect to the role of this Dioscorea species in herbal medicine

Directed Self-Assembly: Expectations and Achievements

Nanotechnology has been a revolutionary thrust in recent years of development of science and technology for its broad appeal for employing a novel idea for relevant technological applications in particular and for mass-scale production and marketing as common man commodity in general. An interesting aspect of this emergent technology is that it involves scientific research community and relevant industries alike. Top–down and bottom–up approaches are two broad division of production of nanoscale materials in general. However, both the approaches have their own limits as far as large-scale production and cost involved are concerned. Therefore, novel new techniques are desired to be developed to optimize production and cost. Directed self-assembly seems to be a promising technique in this regard; which can work as a bridge between the top–down and bottom–up approaches. This article reviews how directed self-assembly as a technique has grown up and outlines its future prospects

Mechanistic studies on the biosorption of Pb(II) by Pseudomonas aeruginosa

The biosorption of Pb(II) ions from aqueous solution has been studied using both the intact and thermolyzed cells of Pseudomonas aeruginosa. Further, the role of the major cell wall components, namely DNA, protein, polysaccharide, and lipid, in Pb(II) binding has been assessed using an enzymatic treatment method. The Pb(II) bioremediation capability of P. aeruginosa cells has been investigated by varying the parameters of pH, time of interaction, amount of biomass, and concentration of Pb(II). The complete bioremoval of Pb(II) using intact cells has been achieved for an initial Pb(II) concentration of 12.4 mg L at pH 6.2 and temperature 29 +/- 1 degrees C. The biosorption isotherm follows Langmuirian behavior with a Gibbs free energy of -30.71d mol(-1), indicative of chemisorption. The biosorption kinetics is consistent with a pseudo-second-order model. The possible Pb(II) binding mechanisms of P. aeruginosa cells are discussed based on characterization using zeta potential measurements, Fourier transform infra-red spectroscopy, and energy dispersive X-ray spectroscopy. The results confirm that among the major cell wall components studied, polysaccharide shows the highest contribution towards Pb(II) binding, followed by DNA, lipid, and protein. Similar studies using thermolyzed cells show higher Pb(II) uptake compared to the intact cells both before and after enzymatic treatment