A recently isolated organism, capable of chemolithoautotrophic growth on dimethyl disulphide, was characterized as a strain of Thiobacillus thioparus. It had DNA with a base composition of 60·5 ± 1·0 mol% G + C, and ubiquinone-8 (UQ-8) as its only respiratory quinone. Its growth in chemostat culture (at a growth rate of 0·07–0·08 h−1) showed yields of 14·4, 11·8 and 2·45 g cell-carbon per mol of dimethyl disulphide (DMDS), dimethyl sulphide (DMS) and thiosulphate, respectively. This is consistent with energy generation from the oxidation of the methyl and the sulphide moieties of DMDS, with oxidation of sulphide to sulphate contributing a yield of about 2·8 g cell-carbon mol−1. From whole organism and cell-free extract studies, DMDS oxidation was shown to proceed by its (NADH-stimulated) reduction to methanethiol (MT), which was oxidized via sulphide, formaldehyde and formate to CO2 and sulphate by MT oxidase, formaldehyde and formate dehydrogenases, and an uncharacterized sulphide-oxidizing system. The MT oxidase had a Km of 9·7 μm and showed substrate inhibition with a Ki of about 8 μm. The essential role of catalase during growth on DMDS was shown by the sensitivity of growth on DMDS (but not on thiosulphate) to 3-amino-1,2,4-triazole. Catalase is believed to destroy the peroxide produced by the MT oxidase reaction. DMDS-grown organisms oxidized sulphide, thiosulphate and tetrathionate (with the latter indicated to be an intermediate in thiosulphate oxidation), suggesting the pathway of sulphide oxidation to be similar to that in some other thiobacilli. Carbon assimilation was by the Calvin cycle, with ribulose bisphosphate carboxylase being present in cell-free extracts at a specific activity of 80 nmol CO2 fixed min−1 (mg protein)−1. Hydroxypyruvate reductase (HPR) was not detected at levels sufficient to indicate any role in primary carbon assimilation.
BejiA.,
IzardD.,
GaviniF.,
LeclercH.,
Leseine-DelstancheM.,
KrembelJ.1987; A rapid chemical procedure for isolation and purification of chromosomal DNA from Gram-negative bacilli.. Analytical Biochemistry 162:18–23
De BontJ.A.M.,
Van DijkenJ.P.,
HarderW.1981; Dimethyl sulphoxide and dimethyl sulphide as a carbon, sulphur and energy source for growth of Hyphomicrobium S.. Journal of General Microbiology 127:315–323
DispiritoA.A.,
LohW.H.-T.,
TuovinenO.H.1983; A novel method for the isolation of bacterial quinones and its application to appraise the ubiquinone composition of Thiobacillus ferrooxidans.
. Archives of Microbiology 135:77–80
HaywoodG.W.,
LargeP.J.1981; Microbial oxidation of amines. Distribution, purification and properties of two primary amine oxidases from the yeast Candida boidinii grown on amines as sole nitrogen source.. Biochemical Journal 199:187–201
KanagawaT.,
DazaiM.,
FukuokaS.1982; Degradation of O,O-dimethyl phosphorodithioate by Thiobacillus thioparus TK-1 and Pseudomonas AK-2.. Agricultural and Biological Chemistry 46:2571–2578
KellyD.P.,
HarrisonA.P.1988; Thiobacillus.. In Bergey’s Manual of Systematic Bacteriology3BryantM. P.,
PfennigN.,
StaleyJ. T.
Edited by Baltimore: Williams & Wilkins (in the Press);
KellyD.P.,
WoodA.P.1984; Potential for methylotrophic autotrophy in Thiobacillus versutus (Thiobacillus sp. strain A2).. In Microbial Growth on C1 Compounds pp 324–329CrawfordR. L.,
HansonR. S.
Edited by Washington, DC: American Society for Microbiology;
KellyD.P.,
ChambersL.A.,
TrudingerP.A.1969; Cyanolysis and spectrophotometric estimation of trithionate in mixture with thiosulfate and tetrathionate.. Analytical Chemistry 41:898–901
LuW.-P.,
KellyD.P.1988; Kinetic and energetic aspects of inorganic sulphur compound oxidation by Thiobacillus tepidarius.
. Journal of General Microbiology 134:865–876
Merck Index1968, 8th Edition.
StecherP. G.
Edited by Rahway, NJ: Merck & Co;
PatelR.N.,
HoareD.S.1971; Physiological studies of methane and methanol oxidizing bacteria: oxidation of C-1 compounds by Methylococcus capsulatus.
. Journal of Bacteriology 107:187–192
SmithN.A.,
KellyD.P.
1988; Isolation and physiological characterization of autotrophic sulphur bacteria oxidizing dimethyl disulphide as sole source of energy.. Journal of General Microbiology 134:1407–1417
StirlingD.I.,
DaltonH.1978; Purification and properties of an NAD(P)+-linked formaldehyde dehydrogenase from Methylococcus capsulatus (Bath).. Journal of General Microbiology 107:19–29
SuylenG.M.H.,
StefessG.C.,
KuenenJ.G.1986; Chemolithotrophic potential of a Hyphomicrobium species, capable of growth on methylated sulphur compounds.. Archives of Microbiology 146:192–198
SuylenG.M.H.,
LargeP.J.,
Van DijkenJ.P.,
KuenenJ.G.1987; Methyl mercaptan oxidase, a key enzyme in the metabolism of methylated sulphur compounds by Hyphomicrobium EG.. Journal of General Microbiology 133:2989–2997
WoodA.P.,
KellyD.P.1985; Physiological characteristics of a new thermophilic obligately chemolithotrophic Thiobacillus species, Thiobacillus tepidarius.
. International Journal of Systematic Bacteriology 35:434–437