Euglena composition

There is also some interplay between the Zn2+ and Mn2+ cations. The RNA polymerase isolated from Euglena gracilis grown on a zinc-deficient medium contains two Zn2+ per molecule but differs from the RNA polymerases isolated from zinc-sufficient cells. The messenger RNA from the zinc-deficient cells had a different base composition, with a two-fold increase in the (G+ C)/(A+U) ratio. Since intracellular [Mn2+] increases in zinc-deficient cells, the effect of [Mn2+] on the RNA polymerase from zinc-deficient cells was investigated. It was shown that increased levels of Mn2+ lead to increased incorporation of GMP relative to UMP.346... 

Schmitt J.M., Bohnert H.-J., Gordon K.H.J., Herrmann R., Bernardi G., Crouse E.J. (1981). Compositional heterogeneity of the chloroplast DNAs from Euglena gracilis and Spinacea oleracea. Eur. J. Biochem. 114 375-382. 

The DNA of a cell can be fractionated according to its base composition (see GC content) by density gradient centrifugation in CsQ. The buoyant density, given as g CsCl/cm , is used to characterize the fractions. Mouse liver DNA, for example, consists of a main fraction (buoyant density 1.702) together with Satellite DNA (see) (1.691). The DNA fractions of Euglena have buoyant densities of 1.707 (nuclear DNA), 1.691 (mitochondrial DNA) and 1.686 (chloroplast DNA). 

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