Genome-enabled analysis of the utilization of taurine as sole source of carbon or of nitrogen by Rhodobacter sphaeroides 2.4.1

Abstract

In the present study, R. sphaeroides 2.4.1 was found to grow exponentially with taurine as the sole source of carbon and energy for growth. When taurine was the sole source of nitrogen in succinate-salts medium, the taurine was rapidly degraded, and most of the organic nitrogen was excreted as the ammonium ion, which was then utilized for growth. Most of the enzymes involved in dissimilation, taurine dehydrogenase (TDH), sulfoacetaldehyde acetyltransferase (Xsc) and phosphate acetyltransferase (Pta), were found to be inducible, and evidence for transcription of the corresponding genes (tauXY, xsc and pta), as well as of tauKLM, encoding the postulated TRAP transporter for taurine, and of tauZ, encoding the sulfate exporter, was obtained by reverse-transcription PCR. An additional branch of the pathway, observed by Novak et al. (2004) (Microbiology 150, 1881-1891) in R. sphaeroides TAU3, involves taurine : pyruvate aminotransferase (Tpa) and a presumptive ABC transporter (NsbABC). No evidence for a significant role of this pathway, or of the corresponding alanine dehydrogenase (Ald), was obtained for R. sphaeroides 2.4.1. The anaplerotic pathway needed under these conditions in R. sphaeroides 2.4.1 seems to involve malyl-CoA lyase, which was synthesized inducibly, and not malate synthase (GlcB), whose presumed gene was not transcribed under these conditions.

The DUF81 protein TauE in Cupriavidus necator H16, a sulfite exporter in the metabolism of C2 sulfonates

“…Taurine dehydrogenase (TauXY) activity could be measured in cell extracts of taurine-grown cells only (Table 2). This corresponded to the inducibility of this enzyme noted elsewhere (Brüggemann et al, 2004;Denger et al, 2006b). Sulfoacetaldehyde acetyltransferase (Xsc) was active in extracts from all sulfonate-grown cells, and absent in extracts from acetate-grown cells (Table 2).…”

Different bacterial strategies to degrade taurocholate

“…Taurocholate was found to be a source of taurine for Bilophila wadsworthia RZATAU (Schumacher et al 1996;Laue et al 1997), but neither taurocholate nor cholate was determined, and Communicated by Walter Reinecke. the pathway of taurine degradation in B. wadsworthia is still incompletely understood. However, an understanding of taurine degradation in other organisms has proceeded further (Cook andDenger 2002, 2006;Denger et al 2006;Gorzynska et al 2006;Cook et al 2007): relevant pathway variants have been found in Delftia acidovorans SPH-1 and in C. testosteroni KF-1 (see below). An understanding of cholate degradation is also being developed (Philipp et al 2006).…”

Sulfoacetate released during the assimilation of taurine-nitrogen by Neptuniibacter caesariensis: purification of sulfoacetaldehyde dehydrogenase

“…The regulator, TauR has been associated with (1) taurine degradative genes since their discovery (e.g., Ruff et al 2003;Brüggemann et al 2004;Denger et al 2006;Gorzynska et al 2006;Baldock et al 2007), with (2) assimilation of taurine nitrogen in R. palustris CGA009 (Denger et al 2004b) (where the same genes [RPB_1035-RPB_1039] are found in R. palustris strains HaA2 and TIE-1), and with (3) assimilation of taurine sulfur, where direct evidence of the function of TauR as a regulatory protein is available (Wiethaus et al 2008). We detected two tauR-like genes (MED92_03198 (tauR2) and MED92_13211 (tauR1)) in the genome of N. caesariensis MED92, and we provisionally annotated the eight open reading frames (ORFs) in the flanking regions ( Fig.…”