Abstract
Nucleic acids showing the predicted 1.93 ratio of 23-S : 16-S RNA were extracted from tobacco leaves, indicating intactness of 23-S chloroplast RNA. Hypochromicity measurements indicated that the RNA was not stabilized by Mg 2+ bound to the RNA. However, heat denaturation at 95 °C followed by rapid cooling to prevent reannealing of any fragments due to “hidden” breaks in the 23-S RNA produced extensive degradation of both chloroplast and cytoplasmic ribosomal RNA species. Escherichia coli 23-S RNA, being stable to heat denaturation, was added as a control to leaf RNA to indicate when degradation at 95 °C had resulted from causes other than “hidden” breaks. By this test, the breakdown of leaf RNA was found to result from the presence of variable traces of ribonuclease, which could not be removed by repeated phenol extraction. However, some of the 23-S RNA would remain resistant to heat denaturation after the nuclease had been removed by extraction with guanidinium chloride. The data suggest that degradation of 23-S RNA obtained by other workers may be due to the presence of “hidden” nuclease in their nucleic acid preparations, rather than a result of in vivo nuclease action.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
