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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 3700

M.N. Golikova, G.V. Selivanova, and L.V. Sokolova; The Effect of Hydrolysis Conditions and Functional State of the Ciliates Paramecium bursaria on the Intensity of the Feulgen Reaction in ther Nuclei. Arch.Protistenk 123:202-214, 1980

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The intensity of the Feulgen reaction in micronuclei and macronuclei of the ciliate Paramecium bursaria was studied under various conditions of acid hydrolysis and in different states of the clones. The shape of the hydrolysis curve proved to depend on the solidity of the DNA-protein complex in the nucleus, in its turn related to the physiological state of the ciliate. In young, rapidly growing clones, the micronuclei stain most intensely after a short-term hydrolysis (about 3-8 min). The DNA-protein complex in them is likely to be loose. In the micronuclei of ciliates from old clones, the maximum of the Feulgen reaction is attained with a much longer hydrolysis (about 20-60 min), which indicates a strong binding of proteins to the DNA and an inhibition of the DNA degradation during hydrolysis. The nuclei of ciliates from clones of medium age stain most strongly with intermediate hydrolysis times (10-20 min). The absorption spectra of the Feulgen-fuchsin reaction product also change with ageing of the clone: the absorption maximum shifts towards longer wavelengths, and the hemiwidth of the spectral band decreases, both phenomena being typical of stronger coupling of the DNA with proteins. The hydrolysis curves of the macronuclei of both normal and amicronucleate clones appear similar to those of the micronuclei of the same clones or clones of comparable age. Hydrolysis in 5N hydrochloric acid at 22 degrees C is preferable to the conventional Feulgen hydrolysis in 1N HCl at 60 degrees C, the intensity of the Feulgen reaction being 30% higher and less dependent on the time and exact temperature of the hydrolysis. Treatment of the slides with the Schiff's reagent at 4 degrees C for 24 hr also produces an increase of the intensity of the reaction in comparison with the standard method (2 hr at room temperature).