Fig. 4. Df(2R)pingpong spermatocytes arrest prior to meiosis I. (A,C) Low and high magnification phase contrast images, respectively, of a testis from pingpong; P{achi} males, which is indistinguishable from wild type. Several stages can be observed, including the mitotically dividing spermatogonia (m), large primary spermatocytes (1°), mature spermatids (s), and the onion stage (o), in which small white nuclei (arrow) and round, dark specialized mitochondria (arrowhead) can be seen. N, a primary spermatocyte nucleus. (B,D) Low and high magnification phase contrast images, respectively, of a testis from a pingpong mutant male. These images are at the same magnification as their wild-type counterparts (A,C). Note that the entire testis is filled with primary spermatocytes but that these cells are not as round or large as in the wild type (arrow in B). The testes shown in A-D were gently squashed with a cover slip to generate thin specimens. The `*' in B indicates the basal region in which cells are degenerating. (E,G) pingpong; P{achi} testes stained for Vis/Achi (green) and DNA (red). In the wild type, several stages can be observed, including cysts in which the DNA is in three diffuse regions per nucleus (mature primary spermatocytes, white arrows), cysts in which the DNA is partially condensed (white arrowhead), and cysts in which the DNA is fully condensed (blue arrowhead). The levels of nuclear Vis/Achi are highest in the mature primary spermatocyte stage and gradually decrease as the cells approach the G₂/M transition. (F,H) pingpong mutant testes stained for DNA (red) and Aly (blue, H only). In the mutant, some chromosomes appear to be partially condensed and others appear fully condensed (*). Aly is still observed in nuclei in the mutant. The images in E and F, and G and H, are at the same magnification and are directly comparable. (I,J) pingpong/CyO (I) and pingpong (J) testes labeled for BrdU incorporation (green) during DNA synthesis. BrdU-labeled 16-cell cysts were observed in both the wild type and mutant. The insets show an example of a labeled cyst at higher magnification. Not all 16 cells are visible in a single focal plane.