The poly-omics of ageing through individual-based metabolic modelling

Abstract Background Ageing can be classified in two different ways, chronological ageing and biological ageing. While chronological age is a measure of the time that has passed since birth, biological (also known as transcriptomic) ageing is defined by how time and the environment affect an individual in comparison to other individuals of the same chronological age. Recent research studies have shown that transcriptomic age is associated with certain genes, and that each of those genes has an effect size. Using these effect sizes we can calculate the transcriptomic age of an individual from their age-associated gene expression levels. The limitation of this approach is that it does not consider how these changes in gene expression affect the metabolism of individuals and hence their observable cellular phenotype. Results We propose a method based on poly-omic constraint-based models and machine learning in order to further the understanding of transcriptomic ageing. We use normalised CD4 T-cell gene expression data from peripheral blood mononuclear cells in 499 healthy individuals to create individual metabolic models. These models are then combined with a transcriptomic age predictor and chronological age to provide new insights into the differences between transcriptomic and chronological ageing. As a result, we propose a novel metabolic age predictor. Conclusions We show that our poly-omic predictors provide a more detailed analysis of transcriptomic ageing compared to gene-based approaches, and represent a basis for furthering our knowledge of the ageing mechanisms in human cells

Water use efficiency and phyto-remediation potential of water hyacinth under elevated CO 2

ABSTRACT A pot culture experiment was conducted in Open Top Chambers during 2007-08. The plantlets (ramets) of water hyacinth were grown in pots with four different media (M1-tap water, M2-distilled water, M3-hoagland solution and M4-hoagland solution with added heavy metals) in three replications and the pots were kept in open top chambers (OTCs), maintained at ambient (360±20ppm) and elevated CO2 (550±30 ppm), and in open field conditions. Pots in three replications from each media-without plant-were kept under the above three conditions as control to measure the evaporation for WUE estimation. The growth of the plants grown in M1 and M2 was severely affected. The plants grown under elevated CO2 and nutrient rich media (M3 and M4) maintained higher green-leaf area over the growth period and recorded higher net assimilation rate (NAR). CO2 enrichment resulted into reduction of water loss (increased WUE) from plants grown in hoagland (M3) and heavy metal (M4) solutions. When the comparison was made in between M3 and M4 treatments, there was tremendous increase in WUE (reduced transpirational loss of water per gram of dry matter produced) in plants grown in M4. the elevated CO2 enhanced the uptake of heavy metals like Cu, Fe, Mn and Zn in both the media but it was higher in M4 than in M3 due to increased availability