(283b) An Arduino based Automatic Pressure Evaluation System (A-APES) to Quantify Growth of Non-Model Anaerobes in Culture

Measuring the growth rate of non-model anaerobic microbes typically requires the use of time-consuming and often destructive manual measurements. Here, an Arduino based Automatic Pressure Evaluation System (A-APES) was developed to automatically measure the rate of fermentation gas production as a proxy for microbial growth in anaerobic systems. The A-APES system measures accumulated gas pressure in sealed cultures accurately at high-resolution, while venting the system at programmed intervals to prevent over pressurization. The utility of A-APES is demonstrated in this study by quantifying the growth rate and phases of a biomass-degrading anaerobic gut fungus, which cannot be otherwise measured via conventional techniques due to its association with particulate substrates. Given the utility of the A-APES approach, we provide a complete construction guide to fabricate the device, which is three times less expensive compared to existing commercial alternatives.

The majority of clinically approved therapeutics target membrane proteins (MPs), highlighting the need for tools to study this important category of proteins. To overcome limitations with recombinant MP expression, whole cell screening techniques have been developed that present MPs in their native conformations. Whereas many such platforms utilize adherent cells, here we introduce a novel suspension cell-based platform termed “biofloating” that enables quantitative analysis of interactions between proteins displayed on yeast and MPs expressed on mammalian cells, without need for genetic fusions. We characterize and optimize biofloating and illustrate its sensitivity advantage compared to an adherent cell-based platform (biopanning). We further demonstrate the utility of suspension cell-based approaches by iterating rounds of magnetic-activated cell sorting (MACS) selections against MP-expressing mammalian cells to enrich for a specific binder within a yeast-displayed antibody library. Overall, biofloating represents a promising new technology that can be readily integrated into protein discovery and development workflows.