Biomedical subjects

Yuzo Inoue

Publications and source records attributed to Yuzo Inoue.

5 recordsLinked to original sources

PubMed2006

Evaluation of mutagenic activities of leachates in landfill sites by micronucleus test and comet assay using goldfish.

To develop a simple system for monitoring the presence of mutagens/carcinogens in the leachates from landfill sites, we used a micronucleus test and a single cell gel electrophoresis (comet) assay originally developed for mice and rats on goldfish (Carassius auratus). The goldfish were exposed for 9 days to the leachate with chemical and biological treatment (treated leachate) or without treatment (raw leachate). The goldfish exposed to several samples died because of the high concentrations of NaCl or ammonium ion (NH4+). In the comet assay using peripheral erythrocytes, the raw leachates showed higher mutagenic activity than the treated leachates. In the micronucleus test, it was difficult to detect the micronuclei in peripheral erythrocytes. On the other hand, the frequency of micronuclei was high in gill cells of goldfish exposed to the raw leachates compared to the treated leachates. A combination of the two bioassays was shown to be useful to evaluate the mutagenic activity of the leachates. We also propose a new scoring method for determination of water quality by using acute toxicity and mutagenic activity.

Animals↗

PubMed2006

Effects of insufficient air injection on methanogenic Archaea in landfill bioreactor.

In this study, methanogenic Archaea diversity in an aerated landfill bioreactor filled with co-disposed incineration bottom ashes and shredded incombustible wastes was monitored and analyzed as a function of time using molecular techniques. Besides, the effects of insufficient air injection on the bioreactor performance and methanogenic diversity were evaluated thoroughly. Results indicated that rapid bio-stabilization of solid waste are possible with aerated landfill bioreactor at various oxygen and oxidation reduction potential levels. Slot-blot hybridization results of leachate samples collected from aerated landfill bioreactor showed that archaeal and bacterial activities increased as stabilization accelerated and bacterial populations constituted almost 95% of all microorganisms. The results of slot-blot hybridization and phylogenetic analysis based on 16S rRNA gene revealed that Methanobacteriales and Methanomicrobiales were dominant species at the beginning while substituted by Methanosarcina-related methanogens close to the end of the operation of bioreactor.

Air↗

PubMed2006

Heavy metal leaching from aerobic and anaerobic landfill bioreactors of co-disposed municipal solid waste incineration bottom ash and shredded low-organic residues.

In this study, heavy metal leaching from aerobic and anaerobic landfill bioreactor test cells for co-disposed municipal solid waste incineration (MSWI) bottom ash and shredded low-organic residues has been investigated. Test cells were operated for 1 year. Heavy metals which were comparatively higher in leachate of aerobic cell were copper (Cu), lead (Pb), boron (B), zinc (Zn), manganese (Mn) and iron (Fe), and those apparently lower were aluminum (Al), arsenic (As), molybdenum (Mo), and vanadium (V). However, no significant release of heavy metals under aerobic conditions was observed compared to anaerobic and control cells. Furthermore, there was no meaningful correlation between oxidation-reduction potential (ORP) and heavy metal concentrations in the leachates although some researchers speculate that aeration may result in excessive heavy metal leaching. No meaningful correlation between dissolved organic carbon (DOC) and leaching of Cu and Pb was another interesting observation. The only heavy metal that exceeded the state discharge limits (10mg/l, to be enforced after April 2005) in the aerobic cell leachate samples was boron and there was no correlation between boron leaching and ORP. Higher B levels in aerobic cell should be due to comparatively lower pH values in this cell. However, it is anticipated that this slightly increased concentrations of B (maximum 25mg/l) will not create a risk for bioreactor operation; rather it should be beneficial for long-term stability of the landfill through faster washout. It was concluded that aerobization of landfills of heavy metal rich MSWI bottom ash and shredded residues is possible with no dramatic increase in heavy metals in the leachate.

Aerobiosis↗

PubMed2006

Impact of chemical components of organic wastes on L(+)-lactic acid production.

Lactic acid production from several organic wastes that had different chemical compositions was examined, and the factors strongly impacting yield were determined. The bioconversion of sugars to lactic acid was affected by the ratio of total sugars to total nitrogen content (the TS/N ratio), and was improved by nitrogen supplementation to adjust the TS/N ratio > or =10. Lactic acid yield was also affected by the fermentable sugars contents, i.e. various oligosaccharides constituted of mainly C6-sugars. The estimation of the fermentable sugars was determined by the total sugars content in starchy materials, such as kitchen wastes, but in lignocellulosic materials, the estimation was affected by the hemicellulose contents. The estimation model of the fermentable sugars was proposed by multivariate analysis using organic components as variables.

Carbohydrate Metabolism↗

PubMed2004

Development of a genotoxicity detection system using a biosensor.

The umu-lux test is a genotoxicity test using the two genetically modified S. typhmurium TA1535 strains (TL210 and TL210ctl) transformed with the luxCDABE (luciferase gene and fatty acid reductase genes) of Vibrio fischeri as a reporter gene. The TL210 strain detects genotoxicants and the TL210ctl strain detects cytotoxicants. In order to develop a highly sensitive, simple and rapid genotoxicity detection system, we constructed a biosensor using these immobilized strains. The biosensor consists of two immobilized microbial membranes, a sample vessel and photodetectors, and the genotoxicity detection system consists of the biosensor, an isothermal box, a photodetector and an air pump. The total measurement time for genotoxicants using this detection system is about 4 h. When 2% (v/v) DMSO was used as a control, the TL210 strain was not emitting light while the TL210ctl strain was. When 0.3 mg/l 4NQO was used as a genotoxicant, TL210 strain and TL210ctl strain were both emitting light. When HgCl2 was used as a cytotoxicant, neither the TL210 strain nor the TL210ctl strain were emitting light. Therefore, the false negative prevention function of a biosensor using the TL210ctl strain has been checked. These results show that our proposed system can correctly detect genotoxicants.

4-Nitroquinoline-1-oxide↗