Publications (2)5.84 Total impact
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Article: Abundance of Zetaproteobacteria within crustal fluids in back-arc hydrothermal fields of the Southern Mariana Trough.
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ABSTRACT: To extend knowledge of subseafloor microbial communities within the oceanic crust, the abundance, diversity and composition of microbial communities in crustal fluids at back-arc hydrothermal fields of the Southern Mariana Trough (SMT) were investigated using culture-independent molecular techniques based on 16S rRNA gene sequences. Seafloor drilling was carried out at two hydrothermal fields, on- and off-ridge of the back-arc spreading centre of the SMT. 16S rRNA gene clone libraries for bacterial and archaeal communities were constructed from the fluid samples collected from the boreholes. Phylotypes related to Thiomicrospira in the Gammaproteobacteria (putative sulfide-oxidizers) and Mariprofundus in the Zetaproteobacteria (putative iron-oxidizers) were recovered from the fluid samples. A number of unique archaeal phylotypes were also recovered. Fluorescence in situ hybridization (FISH) analysis indicated the presence of active bacterial and archaeal populations in the fluids. The Zetaproteobacteria accounted for up to 32% of the total prokaryotic cell number as shown by FISH analysis using a specific probe designed in this study. Our results lead to the hypothesis that the Zetaproteobacteria play a role in iron oxidation within the oceanic crust.Environmental Microbiology 09/2009; 11(12):3210-22. · 5.84 Impact Factor -
Article: Detection of biosphere frontier by using phosphatase activity.
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ABSTRACT: A wide variety of methods have been proposed to detect microbial activities, but most of them can be applied to limited categories of terrestrial organisms. We propose here to use phosphatase activity, which seems to be an essential catalytic activity for all the terrestrial organisms, and possibly for extraterrestrial organisms. We determined phosphatase activity in core samples, chimney samples, and sea water samples obtained in submarine hydrothermal systems located at Suiyo Seamount, Izu-Bonin Arc, and South Mariana. It was shown that phosphatase activity is one of possible biomarkers for extant life.Biological Sciences in Space 12/2004; 18(3):144-5.
