(a) this section of cells in the urine-collecting ducts of the kidney was stained with hematoxylin and eosin, two dyes commonly used in histology. each duct is made of closely packed cells (with nuclei stained red) that form a ring. the ring is surrounded by extracellular matrix, stained purple. (B) this section of a young plant root is stained with two dyes, safranin and fast green. the fast green stains the cellulosic cell walls while the safranin stains the lignified xylem cell walls bright red. (a, from p.r. Wheater et al., Functional histology, 2nd ed. London: Churchill Livingstone, 1987; B, courtesy of stephen grace.)
Figure 9–11 RNA in situ hybridization.
as described in Chapter 8 (see Figure 8–62), it is possible to visualize the distribution of different rnas in tissues using in situ hybridization. here, the transcription pattern of five different genes involved in patterning the early fly embryo is revealed in a single embryo. each rna probe has been fluorescently labeled in a different way, some directly and some indirectly; the resulting images are displayed each in a different color (“false-colored”) and combined to give an image where different color combinations represent different sets of genes expressed. the genes whose expression pattern is revealed here are wingless (yellow), engrailed (blue), short gastrulation (red), intermediate neuroblasts defective (green), and muscle specific homeobox (purple). (From D. kosman et al., Science 305:846, 2004. With permission from aaas.) energy of orbital electronin fuorophore emission of photon 3 second barrier flter: cuts out unwanted fuorescent signals, passing the specifc green fuorescein emission between 520 and 560 nm 2 beam-splitting mirror: refects light below 510 nm but transmits light above 510 nm