Long-term fluorescence hyperspectral imaging of on-chip treated co-culture tumour spheroids to follow clonal evolution.

Multicellular tumour spheroids are an ideal in vitro tumour model to study clonal heterogeneity and drug resistance in cancer research because different cell types can be mixed at will. However, measuring the individual response of each cell population over time is challenging: current methods are either destructive, such as flow cytometry, or cannot image throughout a spheroid, such as confocal microscopy. Our group previously developed a wide-field fluorescence hyperspectral imaging system to study spheroids formed and cultured in microfluidic chips.

Constitutive stable DNA replication in Escherichia coli cells lacking type 1A topoisomerase activity.

Type 1A topoisomerases (topos) are ubiquitous enzymes involved in supercoiling regulation and in the maintenance of genome stability. Escherichia coli possesses two type 1A enzymes, topo I (topA) and topo III (topB). Cells lacking both enzymes form very long filaments and have severe chromosome segregation and growth defects.