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M Eigen

Publications and source records attributed to M Eigen.

90 records · Page 5Linked to original sources
PubMed1976

Determining the base sequence of RNA molecules using continuous degradation kinetics.

A kinetic approach to sequence analysis is presented. A polymer chain composed of a small number of monomer types is degraded continuously with degradation proceeding in only one direction of the chain. Ordinarily, the direct determination of the sequence from the amount of degraded monomers is hampered by the rapid loss of reaction synchrony. However, it is shown, that if the monomers can be measured reasonably accurately, one can solve a system of linear equations with the unknowns giving the positions of the monomers in the chain, and the syn chrony loss due to the stochastic nature of the degradation process can be accounted for. Model calculations are presented.

Base Sequence↗
PubMedDate not supplied

Template-free RNA synthesis by Q beta replicase.

In the absence of extraneously added template, standard preparations of Q beta replicase spontaneously synthesize RNA in vitro, possibly as a result of RNA contamination. Using special enzyme purifications, Sumper and Luce presented evidence that self-replicating RNA not present ab initio can grow out of 'template-free' incorporation mixtures. In contrast to DNA polymerase I and RNA polymerase, which also show de novo synthesis, the products synthesized 'de novo' by Q beta replicase are RNA species containing nonrepetitive sequences of defined lengths which differ between experiments, even when synthesized under identical conditions, in fingerprints, chain lengths and kinetic parameters. Kinetic analysis of the de novo processes distinguished it from template-instructed synthesis and excluded an assumption of self-replicating RNA contamination. These conclusions were questioned recently by Hill and Blumenthal, who claimed to show that highly purified Q beta replicase preparations cannot produce RNA de novo. We now present evidence that, under the conditions required for de novo synthesis, Q beta replicase prepared according to their method is also capable of de novo synthesis. Furthermore, we show that Q beta replicase condenses nucleoside triphosphates to more or less random oligonucleotides.

Base Sequence↗
PubMedDate not supplied

The differentiation of an androgynous imago.

Global phobic-obsessive states accompanied by androgynous images broke, with treatment, into alternating phobic and obsessive phases characterized by paternal images in the former and maternal images in the latter. The dynamics of the phobic states related to the patient's wish for and dread of the paternal phallus, complicated by the father's death during a transitional anal period. The dynamics of the obsessive states were related to wishes and fears of destructiveness of or by the maternal insides. The maternal insides were also experienced as both dangerous and life-giving to the father. As the patient worked through her paternal and maternal fantasies, especially in the transference, her fears of the outside world (the father) and her need to control the insides of her home (the mother) markedly diminished. Active and passive-responsive tendencies bound up and distorted in her obsessive and phobic states were able to undergo fuller differentiation and development with regard to both the internal maternal and paternal objects and the ego's modes of relating to them.

Adult↗