OLIGONUCLEOTIDE PHOTOPRODUCTS FORMED BY PHOTOLYSIS OF POLYRIBOBROMOURIDYLIC ACID

Abstract— Polyribobromouridylic acid was irradiated with 313 nm light at an exposure of ˜ 190 pE/cm*. Oligonucleotides found after RNase hydrolysis of the photolysed poly-rBrU were isolated by DEAE-cellulose chromatography and partially characterized. The dmucleo-tide fraction, found in highest amounts, was not susceptible to hydrolysis by KOH or snake venom phosphodiesterase and may contain a coupled photoproduct. The properties of the dinucleotide were not those of a molecule containing a cyclobutane-type dimer, but were compatible with the properties of a coupled product similar to 5–5'-diuracil. The trinucleotide fraction probably consisted of more than one component. One component may contain a dimeric photoproduct. The tetranucleotide material was sensitive to cleavage into fragments by KOH, and could consist of adjacent photoproducts of the types found in the di- and trinucleotide fractions. The photoproducts formed over a range of lower doses of light were found to have properties similar to those found at high doses.     

A Computer Program to Calculate the Percent Total Deuteration in an Exchange Reaction

The acid-catalyzed hydrogen-deuterium exchange reaction in aliphatic ketones was modeled as a purely random process. Using a computer program, a statistically random hydrogen-deuterium exchange was simulated for a particular molecule, 2-indanone. For this molecule, there are two carbons, each providing two potential sites for exchange. The program determined the relative amounts for each of the partially deuterated species, including the total percent deuteration. A comparison with mass spectral data showed good agreement with this model.     

The Science of Art

Global heat balances with biomass production for aerobic and anaerobic biodigestion of organic matter are proposed. These balances nicely illustrate the thermodynamic differences between these two kinds of biodigestion, and illustrate, in a simple way, a landfills potential for recycling energy originally contained in waste.     

Oscillatory Viscous Flows. Review and Extension

The flow induced by a body oscillating in an unbounded viscousfluid which is otherwise at rest is discussed. Using the techniqueof matched asymptotic expansion a logical and self-consistenttheory is developed. The extensive literature which exists onthis topic is evaluated within the framework of the theory presentedhere.