Purine Auxotrophic Starvation Evokes Phenotype Similar to Stationary Phase Cells in Budding Yeast.

Purine auxotrophy is an abundant trait among eukaryotic parasites and a typical marker for many budding yeast strains. Supplementation with an additional purine source (such as adenine) is necessary to cultivate these strains. If not supplied in adequate amounts, purine starvation sets in. We explored purine starvation effects in a model organism, a budding yeast Saccharomyces cerevisiae ade8 knockout, at the level of cellular morphology, central carbon metabolism, and global transcriptome. We observed that purine-starved cells stopped their cycle in G1/G0 state and accumulated trehalose, and the intracellular concentration of AXP decreased, but adenylate charge remained stable. Cells became tolerant to severe environmental stresses. Intracellular RNA concentration decreased, and massive downregulation of ribosomal biosynthesis genes occurred. We proved that the expression of new proteins during purine starvation is critical for cells to attain stress tolerance phenotype Msn2/4p targets are upregulated in purine-starved cells when compared to cells cultivated in purine-rich media. The overall transcriptomic response to purine starvation resembles that of stationary phase cells. Our results demonstrate that the induction of a strong stress resistance phenotype in budding yeast can be caused not only by natural starvation, but also starvation for metabolic intermediates, such as purines.

Bioeconomy triple factor nexus through indicator analysis.

The transition to a sustainable bioeconomy by a customized approach would speed up its development and make it more targeted. There is still no common international method for determining, measuring and comparing the extent of sustainability. The aim of this research is to develop a methodology for the assessment of bioeconomy-influencing factor interlinkages, and creation of benchmarks through a top-down approach. The main output is the assessment of factor interlinkages that could be further used for composite index creation. A case of triple factor nexus is presented: policy, research and innovations, and technology nexus for EU countries. As a result, the empirical model presents the mathematical description of policy, research and innovation, and technology link benchmark.