Spatial resolution of autoradiograms of rod-shaped organisms

Isotope-containing rod-shaped bacteria approximate a line-segment source for purposes of autoradiography. This is because the width is small and bacteria are usually cylindrically symmetric. For this reason published work has only classified the silver grains longitudinally, independent of the transverse position. While the theoretical integral distribution from a variety of geometric shapes has been calculated, the line-segment has been overlooked because long narrow objects well separated from other sources occur infrequently in eukaryotic biology. This oversight is corrected here. In addition, a simple program for line-segments and ways to combine distributions from separate line-segment sources is presented. Some typical distributions are depicted. The program is used elsewhere in the analysis of wall growth patterns of bacteria.