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Balanced expression of multiple genes is central for establishing new biosynthetic pathways or multiprotein cellular complexes. Methods for efficient combinatorial assembly of regulatory sequences (promoters) and protein coding sequences are therefore highly wanted. Here, we report a high-throughput cloning method, called COMPASS for COMbinatorial Pathway ASSembly, for the balanced expression of multiple genes in Saccharomyces cerevisiae. COMPASS employs orthogonal, plant-derived artificial transcription factors (ATFs) and homologous recombination-based cloning for the generation of thousands of individual DNA constructs in parallel. The method relies on a positive selection of correctly assembled pathway variants from both, in vivo and in vitro cloning procedures. To decrease the turnaround time in genomic engineering, COMPASS is equipped with multi-locus CRISPR/Cas9-mediated modification capacity. We demonstrate the application of COMPASS by generating cell libraries producing β-carotene and co-producing β-ionone and biosensor-responsive naringenin. COMPASS will have many applications in synthetic biology projects that require gene expression balancing.

For years now, the survey of noise deafness as an officially recognized occupational disease has shown agriculture, forestry and the foodstuff industry to be a problem field. This is particularly true of operators of self-propelled machines and tractors. As far as the causes are concerned, it is more or less only presumptions that have been voiced hitherto, since the real noise-exposure data (particularly long-term recordings) has been lacking. For the long-term storage of exposure and audiometry data two reusable computerized projects have been worked out. Employing them, researchers can obtain noise-deafness progression data on an individual basis, based on the individual's noise-exposure data. The preliminary assessment of the data of nearly 1000 workers shows that both the noise exposure and the extent of the hearing loss vary greatly between individuals. This adds the necessity of an individual-based recording of the noise-exposure data.