Actinopolyspora halophila has two separate pathways for betaine synthesis

Citation
A. Nyyssola et M. Leisola, Actinopolyspora halophila has two separate pathways for betaine synthesis, ARCH MICROB, 176(4), 2001, pp. 294-300
Citations number
30
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Microbiology
Journal title
ARCHIVES OF MICROBIOLOGY
ISSN journal
0302-8933 → ACNP
Volume
176
Issue
4
Year of publication
2001
Pages
294 - 300
Database
ISI
SICI code
0302-8933(200110)176:4<294:AHHTSP>2.0.ZU;2-5
Abstract
The extremely halophilic actinomycete Actino-polyspora halophila is a rare example of a heterotrophic eubacterium producing betaine from simple carbon sources. A. halophila synthesized remarkably high intracellular concentrat ions of betaine. The highest betaine concentration, determined at 24% (w/v) NaCl, was 33% of the cellular dry weight. Trehalose was synthesized as a c ompatible solute, accounting for up to 9.7% of the cellular dry weight. The betaine concentration was shown to increase with increasing NaCl concentra tion, whereas the trehalose concentration was highest at the lowest NaCl co ncentration used (15% w/v). A. halophila was capable of accumulating betain e from the medium, while at the same time betaine was also excreted back in to the medium by the cells. Along with the de novo synthesis of betaine, A. halophila was able to take up choline from the medium and oxidize it to be taine. Some basic characteristics of the choline oxidation system are descr ibed. Choline was oxidized to betaine aldehyde in a reaction in which H2O2 generation and oxygen consumption were coupled. Betaine aldehyde was also o xidized, but with lesser efficiency. In addition, betaine aldehyde was oxid ized further to betaine in a reaction in which NAD(P)(+) was reduced.