Bio-Bites!

Eukaryotic chromosome synthesized

The synthesis of a functional eukaryotic chromosome, synIII, based on Saccharomyces cerevisiae chromosome III has been published in Science Volume 4, Issue 334, 2014. Changes to synIII include TAG/TAA stop-codon replacements, deletion of subtelomeric regions, introns, tRNAs, transposons, and silent mating loci, as well as insertion of loxPsym sites to enable genome scrambling. The total synthesis of the synIII chromosome represents a significant step toward the design and complete synthesis of a novel eukaryotic genome structure using the model S. cerevisiae as the basis for a synthetic designer genome. The many changes made to synIII do not appear to significantly decrease the fitness or alter the transcriptome or the replication timing of the synIII strain.¹

Proposed U.S. science budget flat

The proposed 2015 budgets for the major US-based scientific funding agencies, including the National Institutes of Health (NIH), the National Science Foundation (NSF), and the research efforts at the Department of Energy (DOE), are essentially flat. While overall spending on research and development is to increase by 1.2% in 2015, the rate of inflation is expected to be 1.7%, resulting in an overall net loss.^2,3

Engineered bacteria as living detectors

Escherichia coli have been engineered to function as a molecular switch to detect tetracycline exposure in the murine gut. A newly engineered murine E. coli strain, in which the lambda Cro gene is transcribed from a tetracycline-inducible promoter and a “memory element” derived from the cI/Cro region of phage lambda, was generated. When E. coli bearing the memory system are administered to mice treated with anhydrotetracycline, the recovered bacteria all have switched to the Cro state, whereas those administered to untreated mice remain in the cI state.

According to the authors, this work lays a foundation for the use of synthetic genetic circuits as monitoring systems in complex, ill-defined environments and may lead to the development of living diagnostics and therapeutics. Other switches, such as ones that detect inflammation, cancer, or toxins, could also be developed.⁴

GE tobacco produces plant pheromone

A team of Swedish scientists have engineered tobacco plants to synthesize moth mating pheromones. Pheromones are used to perturb mating behavior in insect pests.

By transient expression of up to four genes coding for consecutive biosynthetic steps, multicomponent sex pheromones for two species could be produced. According to the authors, the efficiency and specificity of these mixtures matches the activity of conventionally produced pheromones. The long-term goal of the authors is to design a tailor-made production platform for any moth pheromone component in genetically modified plants, thereby reducing effective cost and hazardous waste.^5,6