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Journal Articles

Fe, Mn and $$^{238}$$U accumulations in ${it Phragmites australis}$ naturally growing at the mill tailings pond; Iron plaque formation possibly related to root-endophytic bacteria producing siderophores

Nakamoto, Yukihiro*; Doyama, Kohei*; Haruma, Toshikatsu*; Lu, X.*; Tanaka, Kazuya; Kozai, Naofumi; Fukuyama, Kenjin; Fukushima, Shigeru; Ohara, Yoshiyuki; Yamaji, Keiko*

Minerals (Internet), 11(12), p.1337_1 - 1337_17, 2021/12

Mine drainage is a vital water problem in the mining industry worldwide because of the heavy metal elements and low pH. Rhizofiltration using wetland plants is an appropriate method to remove heavy metals from the water via accumulation in the rhizosphere. ${it Phragmites australis}$ is one of the candidate plants for this method because of metal accumulation, forming iron plaque around the roots. At the study site, which was the mill tailings pond in the Ningyo-toge uranium mine, ${it P. australis}$ has been naturally growing since 1998. The results showed that ${it P. australis}$ accumulated Fe, Mn, and $$^{238}$$U in the nodal roots without/with iron plaque compared with other plant tissues. Among the 837 bacterial colonies isolated from nodal roots, 88.6% showed siderophore production activities. Considering iron plaque formation around ${it P. australis}$ roots, we hypothesized that microbial siderophores might influence iron plaque formation because bacterial siderophores have catechol-like functional groups. The complex of catechol or other phenolics with Fe was precipitated due to the networks between Fe and phenolic derivatives. The experiment using bacterial products of root endophytes, such as ${it Pseudomonas}$ spp. and ${it Rhizobium}$ spp., showed precipitation with Fe ions, and we confirmed that several ${it Ps.}$ spp. and ${it R.}$ spp. produced unidentified phenolic compounds. In conclusion, root-endophytic bacteria such as ${it Pseudomonas}$ spp. and ${it R.}$ spp., isolated from metal-accumulating roots of ${it P. australis}$, might influence iron plaque formation as the metal accumulation site. Iron plaque formation is related to tolerance in ${it P. australis}$, and ${it Ps.}$ spp. and ${it R.}$ spp. might indirectly contribute to tolerance.

Journal Articles

A Laboratory investigation of microbial degradation of simulant fuel debris by oxidizing microorganisms

Liu, J.; Dotsuta, Yuma; Kitagaki, Toru; Kozai, Naofumi; Yamaji, Keiko*; Onuki, Toshihiko

Proceedings of International Topical Workshop on Fukushima Decommissioning Research (FDR 2019) (Internet), 2 Pages, 2019/05

To decommission the Fukushima Daiichi Nuclear Power Plant (FDNPP), it is necessary to estimate the current status of fuel debris and predicate the possible change under various condition. Some microorganisms may enter the plant due to the seawater injection after accident and future defueling activity. In this study, microbial influence on fuel debris under aerobic condition was experimentally investigated. By culturing some bacteria in the presence of simulant fuel debris in liquid medium, the microbial degradation of fuel debris was observed.

Journal Articles

Root-endophytic Chaetomium cupreum chemically enhances aluminium tolerance in $$Miscanthus sinensis$$ via increasing the aluminium detoxicants, chlorogenic acid and oosporein

Haruma, Toshikatsu*; Yamaji, Keiko*; Ogawa, kazuyoshi*; Masuya, Hayato*; Sekine, Yurina; Kozai, Naofumi

PLOS ONE (Internet), 14(2), p.e0212644_1 - e0212644_16, 2019/02

 Times Cited Count:13 Percentile:87.95(Multidisciplinary Sciences)

Miscanthus sinensis Andersson is a pioneer plant species that grows naturally at mining sites. $$Miscanthus sinensis$$ can detoxify aluminium (Al) by producing phytosiderophores. Root-endophytic Chaetomium cupreum, which produces microbial siderophores, enhances Al tolerance in M. sinensis. We identified the siderophore produced by C. cupreum as oosporein. It was revealed that oosporein could detoxify Al. Inoculation test of C. cupreum onto M. sinensis in acidic mine soil showed that C. cupreum promoted seedling growth, and enhanced Al tolerance.

Journal Articles

Root endophytic bacteria of a $$^{137}$$Cs and Mn accumulator plant, ${{it Eleutherococcus sciadophylloides}}$, increase $$^{137}$$Cs and Mn desorption in the soil

Yamaji, Keiko*; Nagata, Satoshi*; Haruma, Toshikatsu*; Onuki, Toshihiko; Kozaki, Tamotsu*; Watanabe, Naoko*; Namba, Kenji*

Journal of Environmental Radioactivity, 153, p.112 - 119, 2016/03

 Times Cited Count:13 Percentile:52.41(Environmental Sciences)

Of the 463 strains that we isolated, 107 (23.1%) produced the siderophores. We found $$^{137}$$Cs and Mn desorption concomitant with Al and Fe desorption. These results suggest that root endophytes of $$^{137}$$Cs accumulator plant produce siderophores, resulting in the desorption of $$^{137}$$Cs from the contaminated soil collected at Fukushima, Japan.

Oral presentation

Root endophytic Chaetomium cupreum enhanced tolerance of aluminum in Miscanthus sinensis and produced a siderophore

Haruma, Toshikatsu*; Yamaji, Keiko*; Masuya, Hayato*; Sekine, Yurina; Kozai, Naofumi

no journal, , 

Chaetomium cupreum was isolated from the root of Miscanthus sinensis. The siderophore was collected and purified, and the function of the siderophore was investigated. The siderophore was identified as oosporein. C. cupreum increased Al tolerance in M. sinensis via accumulating and detoxifying Al into their mycelia using oosporein, and via changing the Al localization pattern in the roots, which was more efficient to detoxify Al.

Oral presentation

Water purification influence of aquatic plants naturally growing in the slag accumulation site, Ningyo-toge mine

Yamaji, Keiko*; Nakamoto, Yukihiro*; Haruma, Toshikatsu*; Doyama, Kohei*; Ohara, Yoshiyuki; Tanaka, Kazuya; Fukuyama, Kenjin; Fukushima, Shigeru

no journal, , 

no abstracts in English

Oral presentation

Elucidation of radionuclide ($$^{238}$$U) and heavy metal (Fe, Mn) accumulation mechanism in phragmites australis influenced by root endophytic bacteria

Nakamoto, Yukihiro*; Yamaji, Keiko*; Haruma, Toshikatsu*; Doyama, Kohei*; Ohara, Yoshiyuki; Tanaka, Kazuya; Fukuyama, Kenjin; Fukushima, Shigeru

no journal, , 

no abstracts in English

Oral presentation

An Experimental study of microbial effect on simulant fuel debris

Liu, J.; Dotsuta, Yuma; Kitagaki, Toru; Kozai, Naofumi; Yamaji, Keiko*; Onuki, Toshihiko

no journal, , 

Fuel debris was formed in severe accident in nuclear power plant. After the confirmation of microorganisms in water in damaged plant, it is necessary to consider the element migration of fuel debris. Here, some widespread bacteria were applied. By cultivation with simulant fuel debris, the migration mechanism was estimated.

Oral presentation

Isolation of Mn-oxidizing fungi from mine water at Ningyo-toge mine and the culture characteristics

Yamaji, Keiko*; Ohara, Yoshiyuki; Fukuyama, Kenjin; Nagayasu, Takaaki; Haruma, Toshikatsu; Tanaka, Kazuya; Masuya, Hayato*; Habe, Hiroshi*

no journal, , 

no abstracts in English

Oral presentation

Clay mineral dissolution by activities of siderophore producing bacteria

Kimura, Tatsuki; Guido-Garcia, F.; Kozai, Naofumi; Zhang, S.*; Yamaji, Keiko*; Yu, Q.*; Grambow, B.

no journal, , 

To understand bacterial ability to dissolve clay minerals, we isolated siderophore-producing bacteria from white clover roots grown in south Osaka, Japan. The ability to produce siderophores was evaluated by CAS plate method. llite, biotite, vermiculite and nontronite were used for testing as clay minerals. Three different bacteria strains were cultivated. Bacteria cells were centrifuged and washed before inoculation tests. Fifty mg dry weight of bacteria were inoculated into 100 mL modified Balland media and 100 mg of each clay mineral added. The suspension was sampled and new media was added. The concentrations of iron, aluminium and silicon were determined by ICP-OES. The presence of organic molecules was determined by SEC-ICP-OES. The peaks of siderophores were determined using the 405 nm absorbance. As a result, siderophore producing bacteria are able to dissolve clay. This suggests that the effect of siderophore on cesium dissolution is an indirectly process.

Oral presentation

Ba AND Sr adsorption on microbially formed Mn oxide; Implication to removal of Ra from U mining wastewater

Tanaka, Kazuya; Kozai, Naofumi; Yamaji, Keiko*; Masuya, Hayato*; Grambow, B.

no journal, , 

Radium-226, a descendant nuclide of $$^{238}$$U, is of serious concern in Ningyo-toge Environmental Engineering Center because its radioactive concentration in mining wastewater exceeds the effluent standard. In this study, we examined Ba and Sr adsorption on biogenic Mn oxide as a preliminary surrogate for Ra adsorption. Both Ba and Sr show the dependence of adsorption on NaCl concentration. Overall, Ba gave an order of magnitude higher Kd values than Sr. Adsorption behavior of Ra would be similar to that of Ba in terms of ionic radius. Barium showed Kd value greater than 10$$^{5}$$ in 10 mM NaCl solution, similar to the ionic strength of the fresh water system in the Ningyo-toge center. Therefore, it is expected that the biogenic Mn can work effectively for removal of Ra from mining wastewater.

Oral presentation

Adsorption of Ba and Sr on Mn oxide produced by Coprinopsis urticicola strain Mn-2

Tanaka, Kazuya; Kozai, Naofumi; Yamaji, Keiko*; Masuya, Hayato*; Grambow, B.

no journal, , 

Radium-226 is of serious concern in Ningyo-toge Environmental Engineering Center because its radioactive concentration in mining wastewater exceeds the effluent standard. In this study, we examined Ba and Sr adsorption on biogenic Mn oxide as a preliminary surrogate for Ra adsorption. Both Ba and Sr show the dependence of adsorption on NaCl concentration. Overall, Ba gave an order of magnitude higher Kd values than Sr. Adsorption behavior of Ra would be similar to that of Ba in terms of ionic radius. Barium showed Kd value greater than 10$$^{5}$$ mL/g in 10 mM NaCl solution, similar to the ionic strength of the fresh water system in the Ningyo-toge center. Therefore, it is expected that the biogenic Mn can work effectively for removal of Ra from mining wastewater.

Oral presentation

Accumulation of radiocesium by fungi; Implication for radiocesium circulation in forest

Guido-Garcia, F.; Kimura, Tatsuki*; Sakamoto, Fuminori; Kozai, Naofumi; David, K.*; Grambow, B.*; Haruma, Toshikatsu; Yamaji, Keiko*

no journal, , 

Mushrooms (fungi) accumulate radiocesium from soil and believed to control Cs circulation in forest. To elucidate mechanism of fungi-involving radiocesium circulation in forest, we investigated dissolution of mineral by a fungus mycelia (Phlebiopsis gigantean) and local concentration ratios of cesium to potassium, Cs/K, in fruit body of Lentinula edodes (shiitake). The tested fungus has higher ability than a siderophore-producing bacterium to dissolve minerals. Most of the Fe dissolved from minerals were found to be not stable complexes with organic substances. Cs/K values were almost constant in same fruit body specimen of shiitake, revealing that cesium is stored in proportion to potassium at any locations of a shiitake fruit body and there is no specific binding site for cesium in shiitake.

Oral presentation

Microbial community analyses of mine water and inside the iron removal tank in Ningyo-touge mine

Habe, Hiroshi*; Inaba, Tomohiro*; Aoyagi, Tomo*; Aizawa, Hidenobu*; Sato, Yuya*; Hori, Tomoyuki*; Yamaji, Keiko*; Ohara, Yoshiyuki; Fukuyama, Kenjin; Cai, H.*; et al.

no journal, , 

no abstracts in English

Oral presentation

Relationship between vegetation and physical-chemical properties of surface horizon in Ningyo-toge mine

Jiang, X.*; Tamura, Kenji*; Asano, Maki*; Haruma, Toshikatsu; Takahashi, Junko*; Fukuyama, Kenjin; Yamaji, Keiko*

no journal, , 

no abstracts in English

Oral presentation

Micromorphological characteristics of soils under the abandoned fields of mines, Ningyo-toge, Japan

Jiang, Q.*; Tamura, Kenji*; Asano, Maki*; Fukuyama, Kenjin; Takahashi, Junko*; Yamaji, Keiko*

no journal, , 

In the former open-pit mining area of Ningyo-toge mine, ${it Miscanthus sinensis}$ is the dominant in its vegetation and the vegetation succession has been suspended for 2 decades. The present work was conducted to understand the soil micromorphological characteristics on this unusual area. We set two sampling sites (site A and site B) at the former open-pit mining area. Site A is in ${it Miscanthus sinensis}$ dominant vegetation, and site B is in ${it Cyperus microiria}$ dominant vegetation. Soil samples were taken from each horizon of the soil profiles for chemical analysis at the sites, and thin sections were obtained from the soil core samples (0-5 cm, 10-15 cm, 30-35 cm depth of site A and Site B, respectively). The BC horizon of site B has a lower Eh, which may be due to the less voids in the underlying soil, which results in seasonal accumulation of water. And the soil thin section observation showed that the 0-5cm of soil is in good structure, but the lower layer is not fully developed and forms a block structure. The content of the five forms of Fe and Mn are residual form $$>$$ oxide-bound form $$>$$ organic-bound form $$>$$ carbonate-bound form $$>$$ exchangeable form in this study site.

Oral presentation

Elucidation of uranium and heavy metal (Fe, Mn) accumulation mechanism in ${it Phragmites australis}$ influenced by root endophytic bacteria

Nakamoto, Yukihiro*; Yamaji, Keiko*; Haruma, Toshikatsu; Doyama, Kohei*; Ohara, Yoshiyuki; Fukuyama, Kenjin; Fukushima, Shigeru

no journal, , 

no abstracts in English

Oral presentation

Uranium adsorption and iron plaque formation on roots of ${it Phragmites australis}$

Haruma, Toshikatsu*; Doyama, Kohei*; Tanaka, Kazuya; Takahashi, Yoshio*; Fukuyama, Kenjin; Ohara, Yoshiyuki; Yamaji, Keiko*

no journal, , 

no abstracts in English

Oral presentation

Heavy metal accumulations in ${it Phragmites australis}$ growing at the ore-sedimentary site; Iron plaque formation possibly related to endophytic bacteria

Nakamoto, Yukihiro*; Doyama, Kohei*; Haruma, Toshikatsu*; Lu, X.*; Tanaka, Kazuya; Kozai, Naofumi; Fukuyama, Kenjin; Fukushima, Shigeru; Ohara, Yoshiyuki; Yamaji, Keiko*

no journal, , 

no abstracts in English

19 (Records 1-19 displayed on this page)
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