Combinatorial design is an effective strategy to acquire the optimal solution in complex systems. In this study, the combined effects of pathway combination, promoters' strength fine-tuning, copy numbers and integration locus variations caused by δ-integration were explored in Saccharomyces cerevisiae using geranylgeraniol (GGOH) production as an example. Two GGOH biosynthetic pathway branches were constructed.
View Article and Find Full Text PDFHydroxyflutamide (HF), an active metabolite of the first generation antiandrogen flutamide, was used in clinic to treat prostate cancer targeting androgen receptor (AR). However, a drug resistance problem appears after about one year's treatment. AR T877A is the first mutation that was found to cause a resistance problem.
View Article and Find Full Text PDFManipulation of monoterpene synthases to maximize flux towards targeted products from GPP (geranyl diphosphate) is the main challenge for heterologous monoterpene overproduction, in addition to cell toxicity from compounds themselves. In our study, by manipulation of the key enzymes geraniol synthase (GES) and farnesyl diphosphate synthase (Erg20), geraniol (a valuable acyclic monoterpene alcohol) overproduction was achieved in Saccharomyces cerevisiae with truncated 3-hydroxy-3-methylglutaryl-coenzyme reductase (tHMGR) and isopentenyl diphosphate isomerase (IDI1) overexpressed. The expressions of all above engineered genes were under the control of Gal promoter for alleviating product toxicity.
View Article and Find Full Text PDFPerfect matching of an assembled physical sequence to a specified designed sequence is crucial to verify design principles in genome synthesis. We designed and de novo synthesized 536,024-base pair chromosome synV in the "Build-A-Genome China" course. We corrected an initial isolate of synV to perfectly match the designed sequence using integrative cotransformation and clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9)-mediated editing in 22 steps; synV strains exhibit high fitness under a variety of culture conditions, compared with that of wild-type V strains.
View Article and Find Full Text PDFParticipatory appraisal method was adopted to investigate the recent livelihood status of different type farmers and herdsmen's households in the Taipusi Banner of Inner Mongolia agriculture- animal husbandry ecotone, aimed to understand their livelihood strategies and restricting factors and to search for the ways to improve their living standards. The households dealing with pure agricultural production had smaller family size, with older age-structure and lower educational level, and their simple livelihood strategies brought about larger vulnerability and risk. To introduce and expand non-agricultural activities would be the important way to promote the livelihood diversification and to reduce the livelihood risks of these households.
View Article and Find Full Text PDF