Rapidly Developing Yeast Microcolonies Differentiate in a Similar Way to Aging Giant Colonies
Figure 1
Developmental phases and vertical differentiation of yeast microcolonies. (a) Microcolonies develop on GMA-BKP. BKP functions as pH dye indicator with pKa of 6.3, the color of which changes from yellow at acidic pH to purple in more alkali pH. Microcolonies were in the 1st acidic (2 d), alkali (4 d), and beginning of the 2nd acidic (6 d) phases. Bird views of microcolonies are shown. (b) Vertical transversal cross-section viewed by 2PE-CM of akali-phase microcolony formed by the strain producing Ato1p-GFP (left) and scheme of the localization of three cell subpopulations within the microcolony (right). (c) Boundary between Um and Lm cells (left) and morphology of Um and Lm cells (center) of -GFP strain at vertical cross-sections of 4-day-old microcolonies analyzed by 2PE-CM. Cytosolic expression of GFP is used for in situ visualization of Um and Lm cells by 2PE-CM since it enables the visualization of large vacuoles in Lm cells (from which the fluorescence is excluded) and the size of Um and Lm cells. Morphology of Um and Lm cells from 4-day-old BY4742 microcolonies separated by gradient centrifugation and visualized by Nomarski contrast (right). White arrows show large vacuoles in Lm cells; red arrows show lipid droplets in Um cells.
