To explore new microbial resources in deep subsurface oil reservoirs, strain DL-7 was isolated with Hungate technology from oil reservoir water sampled from Dagang oilfield, China. Physiological and biochemical examinations showed that H2/CO2 is the unique substrate of the strain, which cannot metabolize formate, methanol, trimethylamine, acetate and other secondary alcohols. The optimum growth conditions were further identified to be 60 degrees C, pH 7.0-7.5 and 0.25% NaCl. Moreover, the strain cannot grow without yeast extract. Analysis of its 16S rRNA sequence indicated that a similarity of 99.7% presents between the strain and the model species M. marburgensis DSM2133T (X15364).
Hot Temperature ; Methanobacteriaceae ; classification ; genetics ; isolation & purification ; metabolism ; Methanol ; metabolism ; Methanomicrobiaceae ; genetics ; isolation & purification ; Petroleum ; microbiology ; Phylogeny ; RNA, Ribosomal, 16S ; genetics ; Water Microbiology

BACKGROUND/AIMS: Because Methanobrevibacter smithii produces methane, delaying gut transit, we evaluated M. smithii loads in irritable bowel syndrome (IBS) patients and healthy controls (HC). METHODS: Quantitative real-time polymerase chain reaction for M. smithii was performed on the feces of 47 IBS patients (Rome III) and 30 HC. On the lactulose hydrogen breath test (LHBT, done for 25 IBS patients), a fasting methane result ≥10 ppm using 10 g of lactulose defined methane-producers. RESULTS: Of 47, 20 had constipation (IBS-C), 20 had diarrhea (IBS-D) and seven were not sub-typed. The M. smithii copy number was higher among IBS patients than HC (Log₁₀5.4, interquartile range [IQR; 3.2 to 6.3] vs 1.9 [0.0 to 3.4], p<0.001), particularly among IBS-C compared to IBS-D patients (Log₁₀6.1 [5.5 to 6.6] vs 3.4 [0.6 to 5.7], p=0.001); the copy number negatively correlated with the stool frequency (R=−0.420, p=0.003). The M. smithii copy number was higher among methane-producers than nonproducers (Log₁₀6.4, IQR [5.7 to 7.4] vs 4.1 [1.8 to 5.8], p=0.001). Using a receiver operating characteristic curve, the best cutoff for M. smithii among methane producers was Log₁₀6.0 (sensitivity, 64%; specificity, 86%; area under curve [AUC], 0.896). The AUC for breath methane correlated with the M. smithii copy number among methane producers (r=0.74, p=0.008). Abdominal bloating was more common among methane producers (n=9/11 [82%] vs 5/14 [36%], p=0.021). CONCLUSIONS: Patients with IBS, particularly IBS-C, had higher copy numbers of M. smithii than HC. On LHBT, breath methane levels correlated with M. smithii loads.
Area Under Curve ; Breath Tests ; Constipation ; Diarrhea ; Fasting ; Feces ; Humans ; Hydrogen ; Irritable Bowel Syndrome* ; Lactulose ; Methane* ; Methanobrevibacter* ; Real-Time Polymerase Chain Reaction ; ROC Curve ; Sensitivity and Specificity

BACKGROUND/AIMS: Because Methanobrevibacter smithii produces methane, delaying gut transit, we evaluated M. smithii loads in irritable bowel syndrome (IBS) patients and healthy controls (HC). METHODS: Quantitative real-time polymerase chain reaction for M. smithii was performed on the feces of 47 IBS patients (Rome III) and 30 HC. On the lactulose hydrogen breath test (LHBT, done for 25 IBS patients), a fasting methane result ≥10 ppm using 10 g of lactulose defined methane-producers. RESULTS: Of 47, 20 had constipation (IBS-C), 20 had diarrhea (IBS-D) and seven were not sub-typed. The M. smithii copy number was higher among IBS patients than HC (Log₁₀5.4, interquartile range [IQR; 3.2 to 6.3] vs 1.9 [0.0 to 3.4], p<0.001), particularly among IBS-C compared to IBS-D patients (Log₁₀6.1 [5.5 to 6.6] vs 3.4 [0.6 to 5.7], p=0.001); the copy number negatively correlated with the stool frequency (R=−0.420, p=0.003). The M. smithii copy number was higher among methane-producers than nonproducers (Log₁₀6.4, IQR [5.7 to 7.4] vs 4.1 [1.8 to 5.8], p=0.001). Using a receiver operating characteristic curve, the best cutoff for M. smithii among methane producers was Log₁₀6.0 (sensitivity, 64%; specificity, 86%; area under curve [AUC], 0.896). The AUC for breath methane correlated with the M. smithii copy number among methane producers (r=0.74, p=0.008). Abdominal bloating was more common among methane producers (n=9/11 [82%] vs 5/14 [36%], p=0.021). CONCLUSIONS: Patients with IBS, particularly IBS-C, had higher copy numbers of M. smithii than HC. On LHBT, breath methane levels correlated with M. smithii loads.
Area Under Curve ; Breath Tests ; Constipation ; Diarrhea ; Fasting ; Feces ; Humans ; Hydrogen ; Irritable Bowel Syndrome* ; Lactulose ; Methane* ; Methanobrevibacter* ; Real-Time Polymerase Chain Reaction ; ROC Curve ; Sensitivity and Specificity