| Comments |
P.679 left column 2nd paragraph: "Because small differences in diameter produce huge differences in energy cost, the ability to detect and move through chemical gradients may contribute more to a cell's tendency to be rod-like than requirements associated with undirected movement (primary source, ref 217). In addition to the above considerations, bacteria measure chemical gradients about 650 times better if the cells are rod shaped, mainly because spherical cells are affected so much more by Brownian motion and rotational diffusion (primary source). Certainly, though, for cells in any particular environment the most appropriate size and shape will be heavily influenced by the distance to nutrients and the steepness of the gradients leading to their sources. Small cells will be favored in gradients that cover short distances, but wider cells will be more competitive in very long, shallow gradients (ref 217)." |