Satellite DNA in Halobacterium Salinarium: A physical and biochemical study

Abstract

<p> The extremely halophilic bacterium, Halobacterium salinarium, contains a light density satellite DNA component which is 20% of the total DNA. </p> <p> The purpose of this investigation was to study the physical characteristics of the satellite DNA by ultra- centrifugation and electron microscopic methods in an attempt to answer the following questions: "(a) Does the amount of the satellite depend on DNA isolation conditions?" "(b) What is the biological derivation of the satellite?" "(c) What is the physical size( s) of the satellite?" "(d) How many copies of the satellite occur in the"cell?" </p> <p> The results of this investigation showed that the amount of the satellite is independent of isolation conditions, and that it exists in the form of closed circular duplexes. Although the possibility that the satellite represents multiple forms of closed circular molecules could not be completely ruled out, the majority of the closed circles appeared to have lengths about 37 u, so that there might be eight copies of the satellite per bacterial genome. </p>