Single-step method of RNA isolation by acid guanidinium thiocyanate-phenol-chloroform extraction

Intact ribonucleic acid (RNA) has been prepared from tissues rich in ribonuclease such as the rat pancreas by efficient homogenization in a 4 M solution of the potent protein denaturant guanidinium thiocyanate plus 0.1 M 2-mercaptoethanol to break protein disulfide bonds. The RNA was isolated free of protein by ethanol precipitation or by sedimentation through cesium chloride. Rat pancreas RNA obtained by these means has been used as a source for the purification of alpha-amylase messenger ribonucleic acid.

Isolation of biologically active ribonucleic acid from sources enriched in ribonuclease.

Of the colour reactions available for the determination and identification of deoxyribonucleic acid (DNA), the reaction with diphenylamine in a mixture of acetic and sulphuric acids at 1000 (Dische, 1930) has been perhaps the most widely used. The present study arose from the observation that a more intense colour was sometimes produced if, instead of being heated at 1000 for 10 min., the reaction mixture was allowed to stand overnight at room temperature. As a result of this observation the procedure has been modified, principally by adding acetaldehyde to the reagents and by allowing the solution to stand for about 17 hr. at 30° instead of heating it at 1000. The modified method is 3-5 times as sensitive as Dische's original procedure, and several substances which interfere in the original method do not do so in the modified procedure. Some observations on the mechanism of the reaction have been made; in particular it was discovered that there is a liberation of inorganic orthophosphate from DNA during the early stages of the reaction. This finding has a bearing on the structure of DNA. The modified method has already been used in an investigation of nucleic acid metabolism during bacteriophage multiplication (Burton, 1955).

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A study of the conditions and mechanism of the diphenylamine reaction for the colorimetric estimation of deoxyribonucleic acid

A rapid and simple method for measuring thymocyte apoptosis by propidium iodide staining and flow cytometry

In near-physiological concentrations, glucocorticoid hormones cause the death of several types of normal and neoplastic lymphoid cell, but the mechanisms involved are unknown. One of the earliest structural changes in the dying cell is widespread chromatin condensation, of the type characteristic of apoptosis, the mode of death frequently observed where cell deletion seems to be 'programmed'. It is shown here that this morphological change is closely associated with excision of nucleosome chains from nuclear chromatin, apparently through activation of an intracellular, but non-lysosomal, endonuclease.

Glucocorticoid-induced thymocyte apoptosis is associated with endogenous endonuclease activation

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The frequencies of certain sequences of nucleotides in deoxyribonucleic acid.

Formation constants for the complexes of adenosine di- or tri-phosphate with magnesium or calcium ions.

The relation between the synthesis of deoxyribonucleic acid and the synthesis of protein in the multiplication of bacteriophage T2.

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K. Burton

Papers

A study of the conditions and mechanism of the diphenylamine reaction for the colorimetric estimation of deoxyribonucleic acid

The frequencies of certain sequences of nucleotides in deoxyribonucleic acid.

Formation constants for the complexes of adenosine di- or tri-phosphate with magnesium or calcium ions.

The relation between the synthesis of deoxyribonucleic acid and the synthesis of protein in the multiplication of bacteriophage T2.

Free-energy changes of the glutaminase reaction and the hydrolysis of the terminal pyrophosphate bond of adenosine triphosphate.