Precipitation Of RNA Research Articles

Calcium metabolism in tumors--its relationship with chromium complex accumulation. V. The interaction nucleic acid-calcium and the calcification of tumors.

The interaction nucleic acid-calcium was studied <i>in vitro</i>. RNA is precipitated by CaCl₂ while DNA is not. The presence of complexed chromium affects the precipitation of RNA and the physicochemical properties of DNA. The study of the cell fractions from experimental tumors indicate variations in the fraction distribution of calcium and nucleic acids related to the growth stage. The possible role of the cell membranes in the calcification process appears emphasized by the accumulation of calcium and nucleic acids in the microsomal fraction.

Conditions of phenol extraction of RNA from rat liver subcellular cytoplasmic fractions. I. Effect of a precipitation of microsomal RNA on its purity.

Abstract Purification of RNA extracted with phenol from rat liver microsomes by precipitation in sodium benzoate and phenol solutions resulted in the removal of a readily measurable amount of proteins and polysaccharides. The stabilization of RNA was observed by changes in the profiles of the centrifugation gradients. This effect was the same over a wide range of yields in RNA obtained with extraction in the presence of buffers with varying pH levels.

An agar-diffusion method for quantitative determination of ribonuclease

1. 1. A sensitive agar-diffusion slide method has been developed for the assay of ribonuclease activity in microvolumes of samples. 2. 2. The method involves the diffusion of ribonuclease from small wells cut into an RNA-agar-coated microscopic glass slide. 3. 3. Diffusion of ribonuclease results in the production of distinct zones of clearing around the wells after acid precipitation of the unhydrolysed RNA. 4. 4. Conditions for optimal ribonuclease activity on the agar-diffusion slides were determined and the assay was applied to crude tissue extracts.

A simple method for isolating RNA from bacteria

This paper describes a one-step method for the isolation of RNA from bacteria by utilizing the precipitation of RNA in the high salt concentration of pre-layered CsCl gradients.

A simplified assay for RNase activity in crude tissue extracts

A method is described for the precipitation of unhydrolyzed RNA after RNase digestion that avoids the use of strong acids and is extremely sensitive for enzyme assay. The dilution step usually required for spectrophotometric measurements of supernatant fractions after separation from unhydrolyzed RNA is eliminated. The precipitating reagent is buffered lanthanum-magnesium-ethanol added in 10-fold volume to enzyme incubation mixtures. In the macroassay, an increase in absorbancy of 0.41 is obtained with 1 mμg bovine pancreatic RNase after 15 min incubation at 37°. For micromethods, the ethanol can be replaced by Cellosolve (2-ethoxyethanol) and the sensitivity increased 5- to 10-fold.

Purification of protamine sulfate for the quantitative precipitation of ribonucleic acids

A method is described for the purification of protamine sulfate by chromatography on DEAE-cellulose. The precipitation of soluble RNA and ribosomal RNA by purified protamine is quantitative, while oligonucleotides of low molecular weight are not precipitated. The procedure allows the quantitative removal of soluble RNA from solutions and the preparation of soluble RNA samples of high purity.

A PARTIAL FRACTIONATION OF ALKALI‐solUBLE SOIL ORGANIC PHOSPHATE

SummaryA study has been made of the precipitation of soil organic phosphates from alkaline extracts. Acidification to a pH of about 0.4 or below precipitated a small and constant proportion of the extracted organic phosphate. Above pH 0.4 there was an increase in the precipitation up to a pH of about z to 3. The proportion of the phosphate brought down at pH 2.9 could in some cases be increased by prior addition of aluminium sulphate, but in no case did this affect the proportion precipitated at pH 0.2. There was marked precipitation of orthophosphate above pH 3, in the presence of excess aluminium, but below pH 3 it was negligible.Inositol hexaphosphate and DNA were precipitated virtually quantitatively at pH 2.9 in the presence of added aluminium even if the extract was incubated before precipitation. Precipitation of RNA was not complete and could be prevented entirely by prior incubation of the extract. At pH 0.2 DNA was precipitated, but not inositol hexaphosphate. Less than half of a freshly purified sample of RNA was brought down, and no precipitation occurred if the RNA was allowed to stand overnight in alkaline solution before acidification.The soil phosphate esters have been divided into three main classes: an acid‐insoluble fraction precipitated at pH 0.2, and two acid‐soluble fractions, one of which is precipitated at pH 2.9 in the presence of excess aluminium, while the other remains in solution. Part of the acid‐insoluble fraction was readily mineralized during incubation in dilute sodium hydroxide, and some hydrolysis is likely during extraction of the soil with this solvent.