List of Figures
Figure 1. Analogy between the oxygen transfer model and the diffusion/reaction model. (A) Oxygen transfer from the gas bubble into the cell’s cytoplasm and subsequent reaction: (1) Transfer from the interior of the bubble to the gas–liquid interface; (2) Movement across the gas–liquid interface; (3) Diffusion through the relatively stagnant liquid film surrounding the bubble; (4) Transport through the bulk liquid; (5) Diffusion through the relatively stagnant liquid film surrounding the cells; (6) Movement across the liquid–cell interface; (7) Transport through the cytoplasm to the site where the reactions take place; (8) Biochemical reactions involving oxygen consumption. Adapted from Blanch and Clark10; (B) MP transport model in FISH: (1) MP diffusion through the medium to the cell membrane; (2) Membrane uptake of MP; (3) Cytoplasm diffusion within the cells to the nucleus; (4) Reaction between the MP and the target RNA.
Figure 2. Schematic representation of the MP’s diffusion in the bulk. l is the mean distance between the cell-centres, where the maximum distance for a MP to encounter a cell is l/2. This distance was further corrected by removing the diameter of each cell-type, considering the cell in the centre of the cube, in a vertical or horizontal orientation (for non-spherical cells). Considering a three-dimensional movement of the MPs, the mean square displacement (< r (n)2>) is the hypotenuse of the Pythagoras’s theorem for the given geometric volume (r(n)2 = ((l /2)2 + h2).
Figure 3. Variation of the diffusional characteristic time (s) of a 10bp MP with the cellular size of most bacterial and animal cells (in radius, µm) and bulk cellular concentrations (cells/mL).
Figure 4 . Cellular membrane differences between bacterial cells and animal cells. The schematic representation is at scale considering the cell sizes displayed in Table 1. The bacterial cells are represented 5x times magnified.