Eomyidae — Geschichte einer Säugetierf amilie

The history of the fossil rodent family Eomyidae is briefly described. They range from Upper Eocene to Pleistocene time, i. e. about 40 mill, years. Although based mainly on research on dentitions, their phylogeny and intercontinental relationships between North America and Europe are well known. For both continents the phases of radiation are strongly connected to decrease and increase of other rodent groups.     

Presence of a trimethylamine: HS-coenzyme M methyltransferase in Methanosarcina barkeri

A trimethylamine:2-mercaptoethanesulfonate (HS-coenzyme M) methyltransferase has been shown to be present in trimethylamine-grown cells but not in methanol-grown cells of Methanosarcina barkeri. The transfer of one methyl group was catalyzed by this enzyme so that dimethylamine and methyl-S-coenzyme M were the products. Enzyme activity required the presence of ATP and preincubation of the protein solution under H₂. Fifty percent of the maximum activity was obtained under N₂ in the presence of NAD(P)H plus dithioerythritol.Abbreviations HS-coenzyme M 2-mercaptoethanesulfonic acid - methyl-S-coenzyme M 2-(methylthio)ethanesulfonic acid - TES N-tris (hydroxymethyl)-methyl-2-aminoethanesulfonic acid - DTE 1,4-dithioerythritol - BrES 2-bromoethanesulfonic acid - DTT 1,4-dithiothreotol