title: Observation and manipulation of different structural variants of individual cation-DNA complexes in the light microscope.
abstract: Using different preparation protocols, different structures consisting of individual cation-DNA complexes are obtained. Vigorous mixing provides globular complexes, with different degrees of packing when poly-L-lysine or histone H1 is the cation. When hydrodynamic shearing is minimized by gentle handling, molecular networks or single cable like structures can be obtained. After 4',6-diamidino-2-phenyl indole (DAPI) fluorescence staining as well as with bright-field microscopy, the cables can be directly visualized in the light microscope. Using a pulsed ultraviolet laser coupled into the microscope (a laser microbeam) stretches of complex can be cut out from networks of poly-L-lysine-DNA complexes which may serve as models for highly extended chromosomes.
authors.affiliation: Phys. Chemie Institut, Universität Heidelberg, Germany.
authors.forename: N
authors.initials: N
authors.lastname: Endlich
authors.forename: K O
authors.initials: KO
authors.lastname: Greulich
mesh_terms: D010582:Bacteriophage lambda; D002412:Cations; D004247:DNA / Q000737:chemistry* / Q000648:ultrastructure*; D004279:DNA, Viral / Q000737:chemistry / Q000648:ultrastructure; D005456:Fluorescent Dyes; D006657:Histones; D007211:Indoles; D008856:Microscopy, Fluorescence / Q000379:methods; D011107:Polylysine
chemical_list: D002412:Cations; D004279:DNA, Viral; D005456:Fluorescent Dyes; D006657:Histones; D007211:Indoles; D011107:Polylysine; C007293:DAPI; D004247:DNA