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This study evaluates the community structure in nitrifying granules (average diameter of 1600 mum) produced in an aerobic reactor fed with ammonia as the sole energy source by a multivalent approach combining molecular techniques, microelectrode measurements and mathematical modelling. Fluorescence in situ hybridization revealed that ammonia-oxidizing(More)
Microbial population dynamics were investigated during the formation of nitrifying granules in an aerobic upflow fluidized bed (AUFB) reactor fed ammonia as a sole energy source. Analyses of clone libraries of 16S rRNA gene and the ammonia monooxygenase subunit A gene (amoA) revealed that although the clones obtained from the seed sludge were widely(More)
A hollow-fiber membrane chamber (HFMC) was developed as an in situ cultivation device for environmental microorganisms. The HFMC system consists of 48 to 96 pieces of porous hollow-fiber membrane connected with injectors. The system allows rapid exchange of chemical compounds, thereby simulating a natural environment. Comparative analysis through the(More)
Nitrite oxidation is a key step in nitrogen removal in biological wastewater treatment plants. Recently, two phylogenetically different Nitrospira (sublineages I and II) have been recognized as the numerically dominant nitrite-oxidizing bacteria in wastewater treatment plants. However, Nitrospira sublineage II inhabiting activated sludge was not isolated(More)
Loop-mediated isothermal amplification (LAMP) of DNA is a novel technique for the amplification of DNA under isothermal conditions. For the first time, we applied this method to develop a simple and quantitative monitoring method for environmental microorganisms targeting amoA gene in ammonia-oxidizing bacteria. Quantitative analysis was performed first by(More)
DNA computing is a novel method of computing proposed by Adleman (1994), in which the data is encoded in the sequences of oligonucleotides. Massively parallel reactions between oligonucleotides are expected to make it possible to solve huge problems. In this study, reliability of the ligation process employed in the DNA computing is tested by estimating the(More)
The expression of ammonia monooxygenase encoding mRNA (amoA mRNA) in a wastewater treatment process was analyzed in an attempt to propose an effective target for the monitoring of nitrifying bacteria in engineered systems or natural environments. The quick response (1-2 h) of amoA mRNA transcription to the recovery of ammonia oxidation activity induced by(More)
We developed a novel single-stage autotrophic nitrogen-removal process comprised of two composite immobilized biomass layers-one of nitrifying bacteria and one of sulfur-denitrifying bacteria and elemental sulfur-in a Fe-Ni fibrous slag matrix. Nitrification and consumption of dissolved oxygen occurred in the outer part and sulfur denitrification in the(More)
The microbial ecology of nitrifying bacteria in various types of wastewater treatment processes and the dynamic response of the microbial ecology in biofilms were investigated using fluorescence in situ hybridization (FISH) with 16S rRNA-targeted oligonucleotide probes. Nitrifying bacteria were found to exhibit various organizational forms under different(More)
We examined the effects of various NO inhibitors on the healing of DSS-induced rat colitis. Experimental colitis was induced by feeding rats for 6 days with 2.5% DSS in drinking water. After DSS treatment, the animals were fed normally and killed various days up to 7 days later. L-NAME (a nonselective NOS inhibitor) or aminoguanidine (a selective iNOS(More)