High throughput screening of genetically encoded substance libraries
We present a high throughput technology for screening of genetically encoded substances libraries. At the heart of the technology are nL-sized translucent gel-like carriers (?nano-liter reactors? or ?NLRs?) serving as growth compartments for a sensor strain used as a disease model (in our case Micrococcus flavus) and a genetically encoded library (here Lactococcus lactis secreting structurally diverse peptides). Each of NLRs is inoculated via Poisson dilution by approx. 200 cells of the sensor strain and on average one cell of the library. Both, sensor (green) and library (red) cells synthesize a specific fluorescent protein which allows estimation of the amount of sensor and library cells by large particle flow-cytometry. After inoculation, the NLRs are soaked with a growth medium and cultivated in suspensions arrays employing an organic solvent phase as the carrier liquid. The potency of the secreted substance is then determined on the basis of the fluorescence signals whereby a high to modest red paired with a low green signal intensity indicates bioactivity. We will provide an overview of the technical elements of the platform and present the first results of a screening a lantibiotic peptide library ? a substance class featuring a considerable degree of three-dimensionality and larger numbers of bioactive members.