Figure 6

Effects of bistheonellide A (BA) and 2,3-butanedione monoxime (BDM) on endosome movement around the expanding cell plate edge. (A) Schematic representation of the focal plane for image capture around the edge of an expanding cell plate. All microscopic images presented in this figure were focused at the tangential surface of the cell plate. CP represents the cell plate. (B) Interaction of endosomes with the edge of a cell plate. Magnified and time-sequential images of the boxed region in (C) are shown. To facilitate endosome visualization, images are presented in pseudo-color. Movement of an endosome (yellow arrowheads) towards the cell plate (0–4 sec) and merger with the edge (5 sec). (C)-(E) Movement of endosomes stained with FM4-64 around a cell plate in control (C), BA-treated (D) and BDM-treated (E) cells. Images at 0, 15 and 30 sec are colored in red, green, and blue, respectively, and projected together. Scale bars indicate 10 μm.(F)-(H) Tracking of endosomal movement in control (F), BA-treated (G) and BDM-treated (H) cells. Confocal sections were taken at 1-sec intervals for 30 sec, and the endosomes were tracked by ImageJ software (see Methods). (I)-(K) Frequency histograms of endosome velocity over a 30 sec period. Data were obtained from 599 (I), 488 (J), 382 (K) endosomes from 10 control (I), 18 BA-treated (J), and 15 BDM-treated (K) cells, respectively. (L)-(N) Dual observations of MFs (L) and moving endosomes (M and N). To facilitate endosome visualization, images are presented in pseudo-color as in (B). MF structures around the cell plate edge (L) and endosome movement (N, yellow arrowheads) were observed simultaneously. To facilitate visualization of the movement, maximum intensity projections of the time-sequential images are presented (M). Note the movement of an endosome towards the cell plate along the MFs. CP represents the cell plate. Scale bar indicates 5 μm.