title: Heat and alkali induced hyperchromic effects in the ribosomal DNA of sea urchin (Lytechinus variegatus) sperm.
abstract: Melting point dispersion analysis of the ribosomal DNA (rDNA) of sea urchin (Lytechinus variegatus) sperm shows a scatter in the Tm obtained at wavelengths of 230-280 nm at 5 nm intervals. The dispersion curve of the rDNA, which lies in between human thymus DNA and T2 DNA, is probably suggestive of the intragenic heterogeneity. Alkali induced hyperchromic effects, examined over 220-290 nm at 5 nm intervals, show that the hyperchromic effect is minimum at 250 nm, followed by a sharp increase around 270-275 nm. These findings are consistent with the hyperchromic effects produced by alkali-melted G + C--rich DNA of lower organisms.
mesh_terms: D000468:Alkalies / Q000494:pharmacology*; D000818:Animals; D004247:DNA / Q000378:metabolism*; D006358:Hot Temperature; D008297:Male; D012270:Ribosomes / Q000378:metabolism*; D012617:Sea Urchins / Q000378:metabolism*; D013094:Spermatozoa / Q000378:metabolism*
chemical_list: D000468:Alkalies; D004247:DNA