ABSTRACT
Polyamines are widespread distributed all over in living organisms. In Thalassiosira pseudonana 10 N-aminopropyl transferase like nucleotide sequences exists. It is assumed that these sequences are involved in the biomineralization of the diatom shell. The cDNA of the sequences were cloned, recombinant overexpressed and assayed with decarboxylated S-adenosylmethionine and several radioactive labelled polyamines. However, only a spermidine synthase and a thermospermine synthase were found to be enzymatically active in an in vitro assay. Both enzyme activities could be recognized in the crude extracts of Thalassiosira pseudonana and Cyclotella meneghiana. In further investigations the kinetics of the thermospermine synthase was determined and a site-specific mutagenesis of the bindig cavity of decarboxylated S-adenosylmethionine was carried out.
Subject(s)
Biogenic Polyamines/biosynthesis , Diatoms/enzymology , Spermidine Synthase/physiology , Amino Acid Sequence , Chromatography, Thin Layer , Cloning, Molecular , Diatoms/growth & development , Diatoms/metabolism , Escherichia coli/genetics , Molecular Sequence Data , Mutagenesis, Site-Directed , Phylogeny , Reverse Transcriptase Polymerase Chain Reaction , Spermidine Synthase/chemistry , Spermidine Synthase/genetics , Spermidine Synthase/metabolism , Spermine Synthase/genetics , Spermine Synthase/metabolism , Transcription, GeneticABSTRACT
INTRODUCTION: Missing permanent teeth is observed with syndromes or is frequently hereditarily propagated in families. The treatment of these patients is a multi-task of specialists of oral surgery, orthodontics and prosthodontics. DISCUSSION: Despite functional and aesthetic considerations, the main problem of all treatment is that it had to be performed in a growing child. This article discusses the conventional and implant-driven concepts to treat patients from childhood to adolescence with selective or multiple missing permanent teeth.
