On 30 Sep 1999 09:42:41 GMT, jorge1907 at aol.com (Jorge1907) wrote:
>>Any references or is this speculation?
>Actually there is some enrichment as well; unlike many other enterics
>(like E. coli) Salmonella can respire to tetrathionate to form (in all
>likelihood) thiosulfate. Moreover, thiosulfate can serve as an
>electron sink in Salmonella (via the Phs proteins) to form sulfite and
>sulfide; thiosulfate is not reduced in many enterics (like E. coli).
phs is well studied; erika barrett has published extensiely on it.
tetrationate is a bit more obscure but the genetics have been
investigated in valley stewart's lab and john roth's lab. a paper was
published in mol micro in april (a german lab, i forget which)
detailing the ttr locus in salmonella which encodes the reductase.
moreover, this character is used in epidemiologicals studies in
following different outbreaks. in addition, tetrathionate respiration
allows for anaerobic utilization of C2 and C3 compounds which are
unable to support fermentation (like propanediol and ethanolamine);
this was discussed briefly in Annu Rev Genet 50:137 (1996) but would
be more difficult to locate on a medline search. a quick, publicly
available medline search
(http://www4.ncbi.nlm.nih.gov/PubMed/medline.html) pulls up the
1) example outbreak using tetrathionate reductase:
Eur J Epidemiol 1993 May;9(3):251-4
Investigation of an outbreak of Salmonella typhi in a public school in
Usera MA, Aladuena A, Echeita A, Amor E, Gomez-Garces JL, Ibanez C,
Mendez I, Sanz JC, Lopez-Brea M
2) ttr genetics in salmonella:
Mol Microbiol 1999 Apr;32(2):275-87
The genetic basis of tetrathionate respiration in Salmonella
Hensel M, Hinsley AP, Nikolaus T, Sawers G, Berks BC
3) phs characterization:
J Bacteriol 1995 May;177(10):2813-20
Sequence analysis of the phs operon in Salmonella typhimurium and the
contribution of thiosulfate reduction to anaerobic energy metabolism.
Heinzinger NK, Fujimoto SY, Clark MA, Moreno MS, Barrett EL
Gene 1995 Apr 14;156(1):53-7
Cloning and characterization of a gene cluster, phsBCDEF, necessary
for the production of hydrogen sulfide from thiosulfate by Salmonella
Alami N, Hallenbeck PC