Search PubMed⌕ Search

Biomedical subjects

C J Leaver

Publications and source records attributed to C J Leaver.

79 records · Page 5Linked to original sources
PubMed1971

The molecular integrity of chloroplast ribosomal ribonucleic acid.

Instability of chloroplast rRNA has been observed with essentially all chloroplast RNA preparations. This paper describes experiments that show that, under normal conditions of preparation and fractionation, only the heavy chloroplast component (mol.wt. 1.1x10(6)) is unstable, the light chloroplast rRNA (mol.wt. 0.56x10(6)) and the cytoplasmic rRNA species (mol.wt. 1.3x10(6) and 0.70x10(6)) being stable. The stability of the 1.1x10(6)-mol. wt. molecule varies with different plant species, as also does the size and the number of fragments produced. Cleavages in three particular regions of the molecule are very frequent within the range of tissues studied. The 1.1x10(6)-mol.wt. rRNA is, however, stabilized by the presence of Mg(2+) during the preparation and fractionation of the RNA.

Calcium↗
PubMed1968

A detailed evaluation of the possible contribution of bacteria to radioactive precursor incorporation into nucleic acids of plant tissues.

An investigation of the possible contribution of bacteria to the labeling patterns of soybean seedling nucleic acid was made. The results using sucrose gradient, MAK column, and acrylamide gel electrophoretic fractionation together with base composition analyses of nucleic acid preparations show that contaminating bacteria do not contribute to the incorporation of (32)P-orthophosphate into the RNA of excised hypocotyl or soybean root tip. Sterile, non-sterile, and CM-treated soybean hypocotyl synthesize D-RNA to the same extent. The contaminating bacteria do not synthesize an AMP-rich RNA. The G-C rich (32)P-DNA component of the soybean tissues used in these studied results, at least primarily, from the incorporation by contaminating bacteria. CM can be used successfully to eliminate the contribution of bacteria to the labeling of nucleic acids by etiolated plant tissues. Bacterial counts, although valuable, are not sufficient to determine if contaminating bacteria will significantly contribute to nucleic acid labeling in plants.

Journal Article↗