Ecological and genomic profiling of anaerobic methane-oxidizing archaea in a deep granitic environment.

Recent single-gene-based surveys of deep continental aquifers demonstrated the widespread occurrence of archaea related to Candidatus Methanoperedens nitroreducens (ANME-2d) known to mediate anaerobic oxidation of methane (AOM). However, it is unclear whether ANME-2d mediates AOM in the deep continental biosphere. In this study, we found the dominance of ANME-2d in groundwater enriched in sulfate and methane from a 300-m deep underground borehole in granitic rock. A near-complete genome of one representative species of the ANME-2d obtained from the underground borehole has most of functional genes required for AOM and assimilatory sulfate reduction. The genome of the subsurface ANME-2d is different from those of other members of ANME-2d by lacking functional genes encoding nitrate and nitrite reductases and multiheme cytochromes. In addition, the subsurface ANME-2d genome contains a membrane-bound NiFe hydrogenase gene putatively involved in respiratory H2 oxidation, which is different from those of other methanotrophic archaea. Short-term incubation of microbial cells collected from the granitic groundwater with 13C-labeled methane also demonstrates that AOM is linked to microbial sulfate reduction. Given the prominence of granitic continental crust and sulfate and methane in terrestrial subsurface fluids, we conclude that AOM may be widespread in the deep continental biosphere.

Deep microbial life in high-quality granitic groundwater from geochemically and geographically distinct underground boreholes.

Deep granitic aquifer is one of the largest, but least understood, microbial habitats. To avoid contamination from the surface biosphere, underground drilling was conducted for 300 m deep granitic rocks at the Mizunami underground research laboratory (URL), Japan. Slightly alkaline groundwater was characterized by low concentrations of dissolved organic matter and sulfate and the presence of > 100 nM H2 . The initial biomass was the highest (∼10(5) cells ml(-1) ) with the dominance of Hydrogenophaga spp., whereas the phylum Nitrospirae became predominant after 3 years with decreasing biomass (∼10(4) cells ml(-1) ). One week incubation of groundwater microbes after 3 years with (13) C-labelled bicarbonate and 1% H2 and subsequent single-cell imaging with nanometer-scale secondary ion mass spectrometry demonstrated that microbial cells were metabolically active. Pyrosequencing of microbial communities in groundwater retrieved at 3-4 years after drilling at the Mizunami URL and at 14 and 25 years after the drilling at the Grimsel Test Site, Switzerland, revealed the occurrence of common Nitrospirae lineages at the geographically distinct sites. As the close relatives of the Nitrospirae lineages were exclusively detected from deep groundwaters and terrestrial hot springs, it suggests that these bacteria are indigenous and potentially adapted to the deep terrestrial subsurface.

Effects of the inhibition of intestinal P-glycoprotein on aliskiren pharmacokinetics in cynomolgus monkeys.

Aliskiren is a substrate for P-glycoprotein (P-gp) and is metabolized via cytochrome P450 3A4 (CYP3A4). The aim of the present study was to assess whether P-gp influenced the pharmacokinetics of aliskiren and also if drug-drug interactions (DDIs) mediated through P-gp could be reproduced in cynomolgus monkeys. The study investigated the pharmacokinetics of aliskiren in mdr1a/1b gene-deficient (P-gp KO) and wild-type (WT) mice. The area under the plasma concentration-time curve (AUC) following the oral administration of aliskiren was 6.9-fold higher in P-gp KO mice than in WT mice, while no significant differences were observed in the AUC or total plasma clearance following the intravenous administration of aliskiren to P-gp KO mice. Then the pharmacokinetics of aliskiren were evaluated and DDIs between aliskiren and P-gp inhibitors, such as cyclosporin A (CsA) and zosuquidar, examined in cynomolgus monkeys. The AUC for aliskiren were 8.3- and 42.1-fold higher after the oral administration of aliskiren with the concomitant oral administration of zosuquidar and CsA at doses of 10 and 30 mg/kg, respectively. In contrast, the AUC after the intravenous and oral administration of aliskiren was not significantly affected by the oral administration of zosuquidar or intravenous administration of CsA, respectively. These results indicated that P-gp strictly limited the intestinal absorption of aliskiren in mice and monkeys, and also that the effects of intestinal P-gp inhibition by CsA or zosuquidar on the pharmacokinetics of aliskiren were sensitively reproduced in monkeys. In conclusion, aliskiren can be used as a sensitive substrate to evaluate intestinal P-gp inhibition in monkeys.

Biogeochemical signals from deep microbial life in terrestrial crust.

In contrast to the deep subseafloor biosphere, a volumetrically vast and stable habitat for microbial life in the terrestrial crust remains poorly explored. For the long-term sustainability of a crustal biome, high-energy fluxes derived from hydrothermal circulation and water radiolysis in uranium-enriched rocks are seemingly essential. However, the crustal habitability depending on a low supply of energy is unknown. We present multi-isotopic evidence of microbially mediated sulfate reduction in a granitic aquifer, a representative of the terrestrial crust habitat. Deep meteoric groundwater was collected from underground boreholes drilled into Cretaceous Toki granite (central Japan). A large sulfur isotopic fractionation of 20-60‰ diagnostic to microbial sulfate reduction is associated with the investigated groundwater containing sulfate below 0.2 mM. In contrast, a small carbon isotopic fractionation (<30‰) is not indicative of methanogenesis. Except for 2011, the concentrations of H2 ranged mostly from 1 to 5 nM, which is also consistent with an aquifer where a terminal electron accepting process is dominantly controlled by ongoing sulfate reduction. High isotopic ratios of mantle-derived 3He relative to radiogenic 4He in groundwater and the flux of H2 along adjacent faults suggest that, in addition to low concentrations of organic matter (<70 µM), H2 from deeper sources might partly fuel metabolic activities. Our results demonstrate that the deep biosphere in the terrestrial crust is metabolically active and playing a crucial role in the formation of reducing groundwater even under low-energy fluxes.

An EXAFS study on the adsorption structure of phenyl-substituted organoarsenic compounds on ferrihydrite.

Adsorption structures of mono- and diphenyl substituted organoarsenic compounds (PAA and DPAA, respectively) on ferrihydrite were analyzed by extended X-ray absorption fine structure (EXAFS), which suggested that PAA and DPAA form inner-sphere complexes with ferrihydrite regardless of their bulky functional groups. In addition, coexistence of two types of inner-sphere complex modes, i.e. bidentate-binuclear and monodentate surface complexes was suggested by EXAFS fitting with two type of the As-Fe shell.

Contrast-enhanced sonography of pancreatic ductal carcinoma using agent detection imaging.

PURPOSE: The aim of this study was to evaluate the enhancement behavior of pancreatic ductal carcinoma by contrast-enhanced sonography with agent detection imaging (ADI), and to clarify the origin of microbubble signals by comparisons with histological findings of resected specimens. METHODS: The subjects were 21 patients with resectable pancreatic carcinoma. The final histological diagnosis was tubular adenocarcinoma in 20 cases, and anaplastic carcinoma in one case. Ultrasound examinations were performed using an Acuson Sequoia 512 series system, and the contrast agent (Levovist) was injected intravenously in doses of 7 ml (300 mg/ml). The ADI signals (in the tumor) were recorded continuously for 30 s after an injection of Levovist (vascular image) and then obtained intermittently (30 s time-intervals) until the signal had diminished in pancreatic tissue (perfusion image). RESULTS: Contrast enhancement of the tumor was observed in 71.4% of subjects on the vascular image and 76.3% of subjects on the perfusion image. Enhancement patterns on the vascular image were classified into three types: VI-1 (linear enhancement), VI-2 (spotty enhancement), and VI-3 (no enhancement). VI-1, VI-2, and VI-3 were seen in 9 (42.8%), 6 (28.6%), and 6 (28.6%) of the 21 cases, respectively. Enhancement patterns on the perfusion image were classified into four types: PI-1 (diffuse uneven enhancement), PI-2 (spotty enhancement), PI-3 (peripheral enhancement), and PI-4 (negative enhancement). The incidence of PI-1, PI-2, PI-3, and PI-4 was 4.8%, 42.9%, 28.6%, and 23.8%, respectively. With respect to resectable cases, these enhancement patterns were compared with histological findings, i.e., the distribution of blood vessels in the tumor, remaining pancreatic tissues in the tumor, differentiation of types of adenocarcinoma, volume of stroma, and invasion types of carcinoma. The enhanced patterns consequently corresponded to either the distribution of the blood vessels or the remaining pancreatic tissues in the tumor. CONCLUSION: This study indicated that pancreatic ductal carcinoma is frequently enhanced by microbubbles, and the signals seem to originate from fine blood vessels and the remaining pancreatic tissues in the tumor.