title: Whole mount electron microscopy of alkali-urea treated polytene chromosomes spread by centrifugation.
mesh_terms: D000818:Animals; D002498:Centrifugation; D002875:Chromosomes / Q000187:drug effects / Q000648:ultrastructure*; D004331:Drosophila melanogaster; D008854:Microscopy, Electron; D012972:Sodium Hydroxide / Q000494:pharmacology; D014508:Urea / Q000494:pharmacology
chemical_list: D012972:Sodium Hydroxide; D014508:Urea