Dietary quality is an important limiting factor for proper nutrition in many resource poor settin... more Dietary quality is an important limiting factor for proper nutrition in many resource poor settings, with a major concern, micronutrient bioavailability. High content of phytate present in soybean (Glycine max. L) chelates divalent essential mineral ions and reduces its bioavailability and thus dictates the nutritional role of this wonder crop. In this study, the changes in phytate, phytase activity and bioavailability of essential minerals (Fe 2+ , Zn 2+ ,Ca 2+ ) were investigated using various colorimetric assays, AAS and functionally validated using an in vivo simulation model in two Indian cultivars, Pusa 9712 and Kalitur after soaking and germination. Phytate-mineral ratio, another parameter for bioavailability was also analyzed. Phytate content was reduced to 10-13% after 12 hrs of soaking and a further reduction to 46-65% was observed after 72 hrs of germination in Kalitur and Pusa 9712, respectively. Phytate being mainly hydrolyzed by phytase, we observed a six-fold increase in its activity after 72 hrs of germination, compared to control. Considering the dietary role, using an in vivo mimicking approach, a significant increase in the bioavailability of Fe 2+ (8-21%), Zn 2+ (7-18.5%) and Ca 2+ (8-24%) in Kalitur and 9-27% (Fe 2+ ), 9-25% (Zn 2+ ) and 9-23% (Ca 2+ ) in Pusa 9712, respectively was observed after 72 hrs of germination. A negative correlation (p ≤ 0.05) was observed between phytate and mineral bioavailability in sprouted soybean seeds. Thus soybean sprouts enhance the nutritional quality by lowering the anti-nutrient contents and increasing the bioavailability of minerals.
reusable-part condenser [4], and results obtained by others using a non-reusable-part condenser a... more reusable-part condenser [4], and results obtained by others using a non-reusable-part condenser and mass spectrometry (MS) [7].
Phytic acid, the principal storage form of phosphorus in plant seeds accounts for up to 60 to 80%... more Phytic acid, the principal storage form of phosphorus in plant seeds accounts for up to 60 to 80% of the total seed phosphorus content in soybean. Its accumulation increases linearly throughout seed development and it strongly chelates essential mineral cations and charged proteins decreasing their bioavailability. D-Myo-inositol 3-phosphate synthase (MIPS; EC 5.5.1.4), the evolutionarily conserved enzyme in plants, catalyzes the first and the rate limiting step in phytic acid biosynthetic pathway. Aiming at controlling the level of phytate, we monitored the differential expression profile of four, previously reported, members of the MIPS gene family in developing seeds and vegetative tissues of soybean by quantitative real-time PCR (qRT-PCR). Transcript levels were measured relative to the endogenous reference gene eEF-1α (eukaryotic elongation factor 1-alpha) using SYBER-Green. The qRT-PCR data analysis indicated that the expression of the four highly conserved MIPS genes is both temporally and spatially regulated, information much needed for reverse genetic applications. MIPS1 exhibited high transcript levels in the early developing cotyledons with the levels peaking at around 4 to 6 mm seed size stage. Despite of high level of nucleotide sequence conservation amongst the MIPS gene family members, MIPS2, MIPS3 and MIPS4 were poorly expressed in developing seed tissues, although their transcript levels were relatively high in the other organ tissues. MIPS1 was however moderately expressed in seedlings where MIPS2 showed relatively higher expression levels. Among the four isoforms, MIPS4 had the highest transcript levels in the leaf tissue. The data was clearly indicative of the fact that the four isoforms had diverged regulatory elements resulting in their differential expression. Of the four members of the MIPS gene family, MIPS1 is thus the major isoform that had high expression in the developing seed tissues and can be targeted using the dsRNA induced sequence specific RNA degradation mechanism for reduction of phytate levels without affecting the critical aspects of inositol metabolism in other tissues of the plant.
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Papers by Veda Krishnan