Fig 1. Bright-field images (34.8x magnification) of HEK-293S cells growing at 37°C (upper A and C), 30°C (lower A), and 33°C (lower C).

HEK-293S cells were seeded at a density of 5.5 x 10⁵ cells/35 mm Petri dish. The images were taken at 24 and 48 hours using a digital camera mounted on a Carl Zeiss Axiovert S200 microscope (see Methods). Cell number counts per image or 0.22 mm² were plotted in (B) and (D) based on the images shown in (A) and (C), respectively. For each dish, 3 viewing areas were randomly chosen and their images were taken.