Factors affecting nucleic acid extractability in plants

Abstract

Factors affecting the amount and type of isotopically labelled nucleic acid extracted from peanut cotyledons by a two-phase partition system employing phenol were investigated. Nucleic acids isolated at 37° contained some degraded ribosomal RNA, while at 60° ribosomal RNA was severely degraded and DNA was completely eliminated from the aqueous extract. Changing the pH of the extraction medium over a range between 6·0–8·5 had little measurable effect on the type of nucleic acid extracted. However, addition of dupanol (sodium lauryl sulfate) to the extraction medium increased the amount of nucleic acids by 40 per cent, and the specific activity by 50 per cent; little DNA was isolated without dupanol. Differential extraction techniques involving variations in temperature, pH or dupanol gave two different samples of nucleic acid in each case. One contained most of the extractable nucleic acid while the second contained only 4–5 per cent of the total nucleic acid which was composed mostly (as judged by its relatively high specific activity) of newly synthesized ribosomal and messenger RNAs and DNA.