Metabolic engineering of chloroplasts for artemisinic acid biosynthesis and impact on plant growth

Chloroplasts offer high-level transgene expression and transgene containment due to maternal inheritance, and are ideal hosts for biopharmaceutical biosynthesis via multigene engineering. To exploit these advantages, we have expressed 12 enzymes in chloroplasts for the biosynthesis of artemisinic acid (precursor of artemisinin, antimalarial drug) in an alternative plant system. Integration of transgenes into the tobacco chloroplast genome via homologous recombination was confirmed by molecular analysis, and biosynthesis of artemisinic acid in plant leaf tissues was detected with the help of ¹³C NMR and ESI-mass spectrometry. The excess metabolic flux of isopentenyl pyrophosphate generated by an engineered mevalonate pathway was diverted for the biosynthesis of artemisinic acid. However, expression of megatransgenes impacted the growth of the transplastomic plantlets. By combining two exogenous pathways, artemisinic acid was produced in transplastomic plants, which can be improved further using better metabolic engineering strategies for commercially viable yield of desirable isoprenoid products.     

Adequacy of dietary intakes and poverty in India: Trends in the 1990s

Linear programming methods, indicators of nutritional adequacy from the Indian Council of Medical Research and household expenditure survey data from the National Sample Survey Organization were used to construct poverty lines for India. Poverty ratios were calculated for 1993--1994 and 1999--2000 on the basis of nutritional adequacy poverty lines and compared to official estimates of poverty based on energy requirements. Nutritional adequacy poverty lines are higher than official poverty lines, particularly in rural areas. The application of nutritional adequacy poverty lines points to greater rural-urban poverty differences than in official estimates. Declines in rural poverty during the 1990s were also slower under the nutritional adequacy definition, especially in south India. There is a greater degree of rural-urban and regional bias in nutritional adequacy poverty reduction than suggested by official data. Inter-state variations in changes in nutritional poverty and official poverty in the 1990s are largely explained by differences in assumptions on overall price movements. However, relative price movements in food items also played a role, particularly the slow increase in prices of cereals and edible oils in comparison to the prices of pulses, and in some southern states, compared to milk and vegetable prices as well.     

Dynamic dielectrophoretic levitation of living individual cells

The levitation of lone live cells by means of dielectrophoretic force provides a means of determining the relative polarization of the cells and their aqueous support medium. When done over a range of frequencies, a spectrum of dielectric (polarization) responses is obtained which serves to characterize a single living ell. In this manner, individual cells of several microorganisms,Saccharomyces cerevisiae andNetrium digitus, were investigated in the frequency range 10² to 10⁶ Hz. These and related prior studies showed that the positive dielectrophoresis, i.e. where the suspended particle has a greater net polarization than the suspending medium, can be — used to show subtle differences between species, and even between cells of the same culture when using this technique.