We tested whether mixotrophic ciliates are more resistant to solar ultraviolet radiation (UVR) than heterotrophic ones because symbiotic algae can provide self-shading by cell matter absorption and eventually by direct UV screening from mycosporine-like amino acids (MAAs). Sensitivity of a natural assemblage to solar radiation was tested in experiments in the original lake and in a more UV tran...

The fission yeast Schizosaccharomyces pombe switches mating type by transposition of a copy of DNA derived from either of the two storage cassettes, mat2 -P and mat3 -M, into the expression locus, mat1 . The recombinational event of switching is initiated by a double-stranded DNA break present in approximately 20% of the molecules at mat1 . Fifty-three mutants defective in switching of mating t...

Thiosulfate-oxidizing sox gene homologues were found at four loci (I, II, III, and IV) on the genome of Bradyrhizobium japonicum USDA110, a symbiotic nitrogen-fixing bacterium in soil. In fact, B. japonicum USDA110 can oxidize thiosulfate and grow under a chemolithotrophic condition. The deletion mutation of the soxY(1) gene at the sox locus I, homologous to the sulfur-oxidizing (Sox) system in...

Under paddy field conditions, biological sulfur oxidation occurs in the oxidized surface soil layer and rhizosphere, in which oxygen leaks from the aerenchyma system of rice plants. In the present study, we examined community shifts in sulfur-oxidizing bacteria associated with the oxidized surface soil layer and rice roots under different sulfur fertilization conditions based on the 16S ribosom...

135 years ago Ferdinand Cohn, the founder of bacteriology, microscopically observed a conspicuous filamentous bacterium with a complex life cycle and described it as Crenothrix polyspora. This uncultured bacterium is infamous for mass developments in drinking water systems, but its phylogeny and physiology remained unknown. We show that C. polyspora is a gammaproteobacterium closely related to ...

Aquabacterium parvum B6 is a potential nitrate-dependent Fe(II)-oxidizing bacterium. The genes related to its denitrifying mechanism and iron metabolisms were unknown. We present the draft genome of Aquabacterium parvum B6, which could provide further insight into the nitrate-dependent Fe(II)-oxidizing mechanism of strain B6.

Seasonal hypoxia in coastal systems drastically changes the availability of electron acceptors in bottom water, which alters the sedimentary reoxidation of reduced compounds. However, the effect of seasonal hypoxia on the chemolithoautotrophic community that catalyzes these reoxidation reactions is rarely studied. Here, we examine the changes in activity and structure of the sedimentary chemoli...