Abstract
The DNA in isolated chloroplasts was visualized by the fluorescent probe 4'6-diamidino-2-phenylindole (DAPI). When excited with light of 360 nm, the DNA-DAPI complex fluoresces brilliantly at 450 nm. Nuclei also fluoresce but their nucleoli do not. RNase and Pronase treatment of chloroplasts did not affect the fluorescence but both pre- and posttreatment of DAPI-stained chloroplasts with DNase specifically destroyed the fluorescence. DNA-DAPI complexes in the chloroplasts show up as bright dots. These are distributed uniformly within the chloroplast except for the outer margins. The fluorescent dots can be seen at different focal levels. The number of DNA dots is roughly proportional to chloroplast area which, in turn, is a function of leaf size. The number of fluorescent dots also gave the impression that large leaves with large chloroplasts contain more chloroplast DNA than nuclear DNA.
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Selected References
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- Herrmann R. G., Kowallik K. V. Multiple amounts of DNA related to the size of chloroplasts. II. Comparison of electron-microscopic and autoradiographic data. Protoplasma. 1970;69(3):365–372. doi: 10.1007/BF01320301. [DOI] [PubMed] [Google Scholar]
- Kolodner R. D., Tewari K. K. Denaturation mapping studies on the circular chloroplast deoxyribonucleic acid from pea leaves. J Biol Chem. 1975 Jul 10;250(13):4888–4895. [PubMed] [Google Scholar]
- Kolodner R., Tewari K. K. Molecular size and conformation of chloroplast deoxyribonucleic acid from pea leaves. J Biol Chem. 1972 Oct 10;247(19):6355–6364. [PubMed] [Google Scholar]
- Russell W. C., Newman C., Williamson D. H. A simple cytochemical technique for demonstration of DNA in cells infected with mycoplasmas and viruses. Nature. 1975 Feb 6;253(5491):461–462. doi: 10.1038/253461a0. [DOI] [PubMed] [Google Scholar]