Article Figures & Data
Figures
- Fig. 1.
HPLC chromatogram of derivatized CoM (retention time, 2.9 min) from the hydrocarbon-contaminated aquifer. The buffer system used for both HPLC and LC-MS was ammonium acetate-acetonitrile (70:30). (Inset) LC-MS profile of the isoindole derivative of standard CoM (left panel) and the corresponding profile of the environmental sample (right panel). Both spectra show that the ionic molecular weight was 300, which is consistent with the structure of the fluorescent CoM derivative shown.
- Fig. 2.
Absorbance (●), CoM content per milliliter of culture (⧫), and CoM content normalized for culture protein content (■) in a Methanobacterium thermoautotrophicum Marburg culture growing on hydrogen.
- Fig. 3.
(A) Cultures of methanogens tested before and after freezing at −60°C. There was no decrease in the amount of CoM detected in cells due to freezing. (B) Environmental samples tested before and after freezing at −60°C. There were 46 to 83% decreases in the amount of detectable CoM depending on the matrix. Bars indicate standard errors. Abbreviations: Ms., Methanosarcina; Mb. therm, Methanobacterium thermoautotrophicum; Mc. therm.,Methanococcus thermolithotrophicus; Mc.,Methanococcus.
Tables
- Table 1.
Retention times of various thiols when the HPLC procedure is used
Compound Retention time (min) Sulfide 2.75 CoM 2.90 Thiophenol 3.40 1-Octanethiol 3.46 Thioglycolate 3.90 Thiosulfate 3.97 Glutathione 4.10 Heptylmercaptan 4.92 Mercaptosuccinic acid 6.53 Thiosalycilic acid 7.05 2-Bromoethanesulfonic acid 8.49 1-Pentanethiol 8.96 2-Mercaptoethanol 10.63 Cyclopentylmercaptan 10.78 - Table 2.
CoM levels in various methanogens and CoM levels per cell
Organism Amt of CoM Direct count procedure MPN estimation procedure nmol/mg of protein nmol/ml No. of cells/ml fmol of CoM/cell No. of cells/ml fmol of CoM/cell Methanolobus tindarius 11.49 0.56 Methanospirillum hungatei 19.41 0.52 7.40 × 105 0.70 1.1 × 106 0.47 Methanosarcina barkeri (grown on N2-CO2-methanol) 41.11 1.97 4.60 × 106 0.43 Methanosarcina barkeri (grown on N2-CO2-acetate) 6.13 0.70 1.80 × 106 0.39 Methanosarcina barkeri (grown on H2-CO2) 18.21 1.78 Methanosaeta concilli 6.59 0.38 Methanococcus voltae 23.75 1.45 6.20 × 106 0.23 Methanococcus thermolithotrophicus 41.09 2.59 5.15 × 106 0.50 7.5 × 106 0.34 Methanobacterium thermoautotrophicumMarburg 7.48 0.40 2.85 × 106 0.14 1.1 × 107 0.36 - Table 3.
CoM levels in various sediments and CoM levels per cell for sediments
Environmental sample Depth (ft) Amt of CoM MPN estimation procedure nmol/g of sediment nmol/ml No. of cells/ml fmol of CoM/cell Pond sediment 0.02 0.06 1.5 × 105 0.40 Landfill sediment 0.01 0.02 1.1 × 105 0.18 Sewage sludge 0.09 0.22 4.6 × 105 0.48 Hydrocarbon-contaminated sediment 2.5 0.00 NDa ND 3.0 0.02 0.05 7.5 × 104 0.67 4.0 0.08 0.20 3.3 × 105 0.47 5.5 0.07 0.18 2.2 × 105 0.65 7.5 0.08 0.20 3.6 × 105 0.43 8.5 0.07 0.19 2.7 × 105 0.55 10.0 0.07 0.17 1.6 × 105 0.74 ↵a ND, not determined.
