Figure 6

Bud detection and high-temporal-resolution imaging of mitosis. (A) Scenario used to detect and “zoom in” on a particular event (in this case, mitosis). Several positions are monitored and when a condition is fulfilled, image acquisition is performed on only this position at an adapted sampling framerate. (B) Cell cycle progression in yeast. The mitosis event to be captured represents a small-time fraction of the cell’s life cycle (~ 10%). (C) In practice, the acquisition of brightfield images of a population of budding yeast leads to a coarse timelapse with an acquisition framerate of 3 min to search for the next mitotic event. Cell segmentation is used to identify buds (size filtering), shown here as a white overlay. When a bud has reached a given size (and has been growing for at least three frames), we consider that a mitotic event is about to occur. (D) Then, the acquisition software “zooms in” on that cell by increasing the framerate to one frame every 30 s for 20 min and RFP imaging is added to image the nucleus (HTB2-mCherry reporter). As shown in panel (D), this scenario allows the complete mitotic event and nuclear separation between the mother and daughter cells (around 10 min, as expected) to be captured at an appropriate framerate. Once this image acquisition sequence is complete, the program resumes its search at the lower framerate for another mitotic event.