Te 2000 u wide field inverted microscope

The time-lapse studies were carried out using poly-d-lysine coated MatTek glass-bottom Petri dishes of 35 mm, with a 14 mm microwell and a No. 1.5 cover glass. The untreated bacteria (5 × 10⁸ CFU mL⁻¹) were mixed on 96-well plates (100 μL sample per well) to give a final concentration of 100 μM Ent/DGE conjugate. Once the conjugate was added to the culture, a 5 μL sample from each suspension was pipetted out onto the 14 mm microwell and covered with an agarose pad (1% w/w agarose/Milli-Q water). The Petri dish with the sample was then immediately covered with the No. 1.5 coverslip and placed on the microscope stage for imaging at 37 °C. Image acquisition was carried out at 5 min intervals over 4.5–5 h. The time-lapse images were collected on a Nikon-TE 2000 U wide-field inverted microscope equipped with a 100× oil-immersion objective lens.