| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Department of Biological Sciences, The University, D-78457 Konstanz, Germany
Correspondence
Alasdair Cook
alasdair.cook{at}uni-konstanz.de
The Gram-positive bacteria Rhodococcus opacus ISO-5 and Rhodococcus sp. RHA1 utilized taurine (2-aminoethanesulfonate) as the sole source of carbon or of nitrogen or of sulfur for growth. Different gene clusters and enzymes were active under these different metabolic situations. Under carbon- or nitrogen-limited conditions three enzymes were induced, though to different levels: taurine-pyruvate aminotransferase (Tpa), alanine dehydrogenase (Ald) and sulfoacetaldehyde acetyltransferase (Xsc). The specific activities of these enzymes in R. opacus ISO-5 were sufficient to explain the growth rates under the different conditions. These three enzymes were purified and characterized, and the nature of each reaction was confirmed. Analyses of the genome of Rhodococcus sp. RHA1 revealed a gene cluster, tauR-ald-tpa, putatively encoding regulation and oxidation of taurine, located 20 kbp from the xsc gene and separate from two candidate phosphotransacetylase (pta) genes, as well as many candidate ABC transporters (tauBC). PCR primers allowed the amplification and sequencing of the tauR-ald-tpa gene cluster and the xsc gene in R. opacus ISO-5. The N-terminal sequences of the three tested proteins matched the derived amino acid sequences of the corresponding genes. The sequences of the four genes found in each Rhodococcus strain shared high degrees of identity (>95 % identical positions). RT-PCR studies proved transcription of the xsc gene when taurine was the source of carbon or of nitrogen. Under sulfur-limited conditions no xsc mRNA was generated and no Xsc was detected. Taurine dioxygenase (TauD), the enzyme catalysing the anticipated desulfonative reaction when taurine sulfur is assimilated, was presumed to be present because oxygen-dependent taurine disappearance was demonstrated with taurine-grown cells only. A putative tauD gene (with three other candidates) was detected in strain ISO-5. Regulation of the different forms of metabolism of taurine remains to be elucidated.
The GenBank accession numbers for the sequences reported in this paper are: xscISO-5, AY498611; tauR-ald-tpaISO-5, AY498612.
This article has been cited by other articles:
|
|
 |
|
  K. Denger, T. H. M. Smits, and A. M. Cook Genome-enabled analysis of the utilization of taurine as sole source of carbon or of nitrogen by Rhodobacter sphaeroides 2.4.1. Microbiology, November 1, 2006; 152(Pt 11): 3197 - 3206. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Weinitschke, K. Denger, T. H. M. Smits, K. Hollemeyer, and A. M. Cook The sulfonated osmolyte N-methyltaurine is dissimilated by Alcaligenes faecalis and by Paracoccus versutus with release of methylamine. Microbiology, April 1, 2006; 152(Pt 4): 1179 - 1186. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
S. Weinitschke, K. S. von Rekowski, K. Denger, and A. M. Cook Sulfoacetaldehyde is excreted quantitatively by Acinetobacter calcoaceticus SW1 during growth with taurine as sole source of nitrogen Microbiology, April 1, 2005; 151(4): 1285 - 1290. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A. J. Wolfe The Acetate Switch Microbiol. Mol. Biol. Rev., March 1, 2005; 69(1): 12 - 50. [Abstract] [Full Text] [PDF]
|
|
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| INT J SYST EVOL MICROBIOL | MICROBIOLOGY | J GEN VIROL |
| J MED MICROBIOL | ALL SGM JOURNALS | |
