Enzyme induction in Escherichia coli is stimulated by certain 5-amino-2,4-bis(substitutedamino)pyrimidines (Kunkee, 1960a). Other 2,4diaminopyrimidines have been reported to be antagonists of folic acid (Hitchings et al., 1952; Doctor, 1956). Since there are indications that the stimulation of enzyme induction involves nucleic acid metabolism (Kunkee, 1960b) and since folic acid is involved in ...

NUCLEIC ACID. By J. F. Danielli and R. Brown. Symposia of the Society for Experimental Biology, No. 1. Cambridge University Press. The Macmillan Co., New York, 1947. vi + 290 pp. $8.50 This volume presents the papers read at a symposium of the Society for Experimental Biology held at Cambridge in July 1946. The reader will find much basic material pertaining to current concepts of the chemistry...

Several investigators (Creaser, 1955; Pardee, 1955; Spiegelman et al., 1955; Horowitz et al., 1958) have shown inhibition of enzyme induction by pyrimidine and purine analogues. The inhibition results apparently from interference with nucleic acid synthesis. In experiments with other compounds which might interfere with nucleic acid metabolism, we found a stimulation of enzyme induction in Esch...

Isolation of newly synthesized mercurated RNA transcripts by chromatography on sulfhydryl-agarose has recently been used to reduce contamination by endogenous RNA derived from the chromatin template. We show that substantial RNA aggregation occurs during standard isolation procedures, causing significant retention of endogenous (unmercurated) RNA on sulfhydryl-agarose. We describe methods to re...

DNA stable-isotope probing (DNA-SIP) is a powerful technique for identifying active microorganisms that assimilate particular carbon substrates and nutrients into cellular biomass. As such, this cultivation-independent technique has been an important methodology for assigning metabolic function to the diverse communities inhabiting a wide range of terrestrial and aquatic environments. Following...

In the near future personalized medicine with nucleic acids will play a key role in molecular diagnostics and therapy, which require new properties of the nucleic acids, like stability against enzymatic degradation. Here we demonstrate that the replacement of nucleobases with PNA by functional molecules harbouring either a dienophile or a diene reactivity is feasible and confers all new options...

Cationic amphipathic pH responsive peptides possess high in vitro and in vivo nucleic acid delivery capabilities and function by forming a non-covalent complex with cargo, protecting it from nucleases, facilitating uptake via endocytosis and responding to endosomal acidification by being released from the complex and inserting into and disordering endosomal membranes. We have designed and synth...

of radioautographic techniques (Logan, Ficq & Errera, 1959). This permits the study of incorporation experiments in individual nuclei but does not give any information about the quantitative chemical changes in the nuclei. It is of interest to know whether there are any common biochemical changes in the nuclei as a result of feeding the two carcinogens. However, the two types of nuclear prepara...

Friedreich's ataxia is an incurable genetic disorder caused by a mutant expansion of the trinucleotide GAA within an intronic FXN RNA. This expansion leads to reduced expression of frataxin (FXN) protein and evidence suggests that transcriptional repression is caused by an R-loop that forms between the expanded repeat RNA and complementary genomic DNA. Synthetic agents that increase levels of F...

NUCLEIC ACID. By J. F. Danielli and R. Brown. Symposia of the Society for Experimental Biology, No. 1. Cambridge University Press. The Macmillan Co., New York, 1947. vi + 290 pp. $8.50 This volume presents the papers read at a symposium of the Society for Experimental Biology held at Cambridge in July 1946. The reader will find much basic material pertaining to current concepts of the chemistry...