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Biology subjects

Joensson, H. N.

Publications and source records attributed to Joensson, H. N..

2 recordsLinked to original sources

High-throughput cell spheroid production and assembly analysis by microfluidics and deep learning

3D cell culture models are an important tool in translational research but have been out of reach for high-throughput screening due to complexity, requirement of large cell numbers and inadequate standardization. Here, we present a high-throughput workflow to produce and characterize the formation of miniaturized spheroids using deep learning. We train a convolutional neural network (CNN) for cell ensemble morphology classification, benchmark it against more conventional image analysis, and characterize spheroid assembly determining optimal surfactant concentrations and incubation times for spheroid production for three cell lines with different spheroid formation properties. Notably, this format is compatible with large-scale spheroid production and screening. The presented workflow and CNN offer a template for large scale minispheroid production and analysis and can be extended and re-trained to characterize morphological responses in spheroids to additives, culture conditions and large drug libraries.

bioengineering↗

Pooled CRISPRi screening of the cyanobacterium Synechocystis sp. PCC 6803 for enhanced growth, tolerance, and chemical production

We developed an inducible CRISPRi gene repression library in the cyanobacterium Synechocystis sp. PCC 6803, where all annotated genes are targeted for repression. We used the library to estimate gene fitness in multiple conditions. The library revealed several mutants with increased specific growth rates (up to 17%), and transcriptomics of these mutants revealed common upregulation of genes within photosynthetic electron flow. We challenged the library with L-lactate stress to find more tolerant mutants. Repression of the peroxiredoxin Bcp2 increased growth rate by 49% in the presence of 0.1 M L-lactate. Finally, the library was transformed into a L-lactate-secreting strain, and droplet microfluidics sorting of top producers enriched sgRNAs targeting nutrient assimilation, redox modulation, and cyclic-electron flow. Several clones showed increased productivity in batch cultivations (up to 75%). In some cases, tolerance or productivity was enhanced by partial repression of essential genes, which are difficult to access by transposon insertion.

microbiology↗