Effect of UV Rays on Hypha Growth of Morchella esculenta, Trichotoma matsutake and Collybia velutipes

From the paper

Abstract

Addition of initiation factor IF3 to solutions of E. coli ribosomes dramatically alters their behavior in pressure-jump relaxation kinetic experiments in which 90 degrees light-scattering is used to monitor the macromolecular reaction. The effect of IF3 on relaxation processes attributed to "tight" couples is strongly dependent on the Mg2+ concentration. At 2.5 mM Mg2+, addition of 1 molar equivalent of IF3 decreases the relaxation amplitude by a factor of 3 relative to ribosome solutions without IF3. However, at 5.0 mM Mg2+, addition of 1 molar equivalent of IF3 produces a marked increase in the relaxation amplitude, by a factor of 2-8 fold relative to ribosomes in the absence of IF3. IF3 has no effect on the relaxation process attributed to "loose" couples at 10 mM Mg2+. While we are unable to propose a precise mechanism for IF3 action with the data on hand, our results require that the 30S. IF3 complex either reacts with the 50S subunit, forming a 70S. IF3 intermediate, or acts as a pool of reactive 30S subunit. Further kinetic evidence is required to distinguish between these possible pathways.