Contents of hepatic and renal metallothioneins in Hyposarcus pardalis: for construction of biomarker for heavy metal contamination in environments     

Shun Yukawa  Yustiawati  M. Suhaemi Syawal  Kenichi Kobayashi  Toshiyuki Hosokawa  Takeshi Saito  Shunitz Tanaka  Masaaki Kurasaki 《Environmental Earth Sciences》2014,71(4):1945-1952

The pollution of water by heavy metals is one of the most serious problems in the developing countries, where watercourses play important roles in transport and economic activities. The aim of this study was to examine whether Hyposarcus pardalis, a fish species widespread in the freshwater environment in Indonesia, could be used as a biomarker for environmental pollution by metals. To this effect, the concentrations of metallothioneins and metals in the livers and kidneys of H. pardalis were measured. In addition, to clarify the relationship between metallothionein concentrations and metal exposure, the concentrations of metallothioneins and metals were determined in the liver and the kidney of fish exposed to 50 and 500 ppb Cu and 500 ppb Mn, compared with those kept in clean water. Sufficient concentrations of metallothionein were detected in fish captured from Lake Rawakalong located in an industrial area in the suburbs of Jakarta. The results of exposure experiments suggested that H. pardalis retained a history of pollution in its organs for a long duration, and the metals bound to metallothioneins in the liver and kidney could be replaced with Cu following exposure. In conclusion, the hepatic and renal metallothioneins in H. pardalis are a useful candidate biomarker for monitoring heavy metal contamination.  相似文献   

Characteristics and climatic sensitivities of runoff from a cold‐type glacier on the Tibetan Plateau     

Koji Fujita  Takeshi Ohta  Yutaka Ageta 《水文研究》2007,21(21):2882-2891

Model calculations are made in order to understand the characteristics and response to climate change of runoff from a cold glacier on the Tibetan Plateau. Some 20% of meltwater is preserved at the snow–ice boundary due to refreezing, since the glaciers in mid to northern Tibet are sufficiently cooled during the previous winter. Sensitivity to alterations in meteorological parameters has revealed that a change in air temperature would cause not only an increase in melting by sensible heat, but also a drastic increase in melting due to lowering of the albedo, since some of the snowfall changes to rainfall. In addition, it was suggested that a decrease in precipitation would cause a lowering of the surface albedo, with a resulting increase in the contribution of glacier runoff to the total runoff of river water. This study shows the first quantitative evaluation of the above effects, though they have been suggested qualitatively. The seasonal sensitivity of glacier runoff was examined by changing the dates given for a meteorological perturbation for a period of only 5 days. It was revealed that changes in both air temperature and precipitation during the melting season strongly affected glacier runoff by changing the surface albedo, though these perturbations only slightly altered the annual averages. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

Volatilization properties of gasoline components in soils   总被引：1，自引：0，他引：1  

Junko Nishiwaki  Yoshishige Kawabe  Yasuhide Sakamoto  Takeshi Komai  Ming Zhang 《Environmental Earth Sciences》2011,63(1):87-95

Understanding the volatilization properties of gasoline components in soils is of fundamental importance in the field of geoenvironments. A series of experiments were performed to investigate the effects of temperature, soil water content, soil organic matter content, as well as mean particle size on volatilization rate of total petroleum hydrocarbons (TPH) and the paraffin (n-paraffin and isoparaffin), olefin, naphthene, and aromatic (PONA) components in four typical Japanese soils. The results of this study can be summarized as follows. (1) Volatilization rate of gasoline in a soil is concentration-dependent; extensive volatilization occurs above a certain threshold, while volatilization becomes very slow below this threshold. (2) Compared to other factors, temperature and soil organic matter content have greater effects on volatilization rate of gasoline in soils. The volatilization rate is proportional to temperature, but inversely related to soil organic matter content. (3) The characteristics of time-dependent decreases of TPH and PONA components in soils are similar. The volatilization rate of olefin is higher than those of other components. In addition, volatilization of olefin is also more sensitive to temperature as well as organic matter content.  相似文献   

Discriminating residual and colluvial soils using topographic analysis in a small,forested catchment in Japan     

Kenji Maeda  Takafumi Tanaka  Ohta Takeshi  Shigeaki Hattori 《水文研究》2007,21(16):2144-2156

Soil moisture plays an important role in hydrology. Understanding factors (such as topography, vegetation, and meteorological conditions) that influence spatio‐temporal variability in soil moisture, and how this influence is manifested, is important for understanding hydrological processes. A number of distributed (quasi‐)physical hydrological models have been developed to investigate this subject. Previous studies have shown that the spatial differences in the distribution of soil types (residual and colluvial soils) dominantly reflect spatio‐temporal fluctuations in soil moisture and runoff. We present a methodology for assessing the spatial distribution of residual and colluvial soils, which differ with respect to their physical characteristics, in a 0·88 km² forested catchment with complex topography and a complex land‐use history. Our method is based on penetration resistance profile data; in this data set, each data point represents soil physical characteristics within an area of about 25 m². If the spatial distribution of soils under similar meteorological, geological, historical land use, and other conditions could be characterized on the basis of similarity in topographic features, then the spatial distribution of soil could be predicted based on relationships between various topographic indices (e.g. topographic index and local slope). We tested whether our model correctly assessed the reference data. The model's results were 90·5% correct for residual soils and 87·3% correct for colluvial soils. Further studies will quantify the relationships between topographic features of land covered by residual and colluvial soils and changes in spatio‐temporal variations in the catchment (e.g. vegetation and land use) as a function of geology or meteorology. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

Mineral Components and Anti-oxidant Activities of Tropical Seaweeds     

Suzuki Takeshi Yoshie-Stark Yumiko Santoso Joko 《中国海洋大学学报(英文版)》2005,4(3):205-208

Seaweeds are known to hold substances of high nutritional value; they are the richest resources of minerals important to the biochemical reactions in the human body. Seaweeds also hold non-nutrient compounds like dietary fiber and polyphenols. However, there is not enough information on the mineral compounds of tropical seaweeds. Also we are interested in the antioxidant activities of seaweeds, especially those in the tropical area. In this study, Indonesian green, brown and red algae were used as experimental materials with their mineral components analyzed by using an atomic absorption spectrophotometer. The catechins and flavonoids of these seaweeds were extracted with methanol and analyzed by high performance liquid chromatography （HPLC） ; the anti-oxidant activities of these seaweeds were evaluated in a fish oil emulsion system. The mineral components of tropical seaweeds are dominated by calcium, potassium and sodium, as well as small amounts of copper, iron and zinc. A green alga usually contains epigallocatechin, gallocatechin, epigallocatechin gallate and catechin. However, catechin and its isomers are not found in some green and red algae. In the presence of a ferrous ion catalyst, all the methanol extracts from the seaweeds show significantly lower peroxide values of the emulsion than the control, and that of a green alga shows the strongest anti-oxidant extract of this alga, which is significantly different from activity. The highest chelation on ferrous ions is also found in the the other methanol extracts in both 3 and 24 h incubations.  相似文献   

Construction of Wide Field Cryogenic Telescope     

Minoru Ando  Tetsuya Nagata  Shuji Sato  Makoto Watanabe  Kunio Itoh  Toshihide Kawai  Hidehiko Nakaya  Yoshiharu Namba  Takeshi Takezawa 《Experimental Astronomy》2002,13(3):119-134

We constructed a wide field cryogenic telescope (WFCT) containing a whole Ritchey-Chrétien system and a focal plane array in a cryostat for near infrared observations to cover the field of view of 0.4°. The telescope has a primary mirror of 220 mm and an engineering grade 256 × 256 InSb array. The optical components such as two mirrors, filters, spiders, and radiation shield tube are cooled down to 180 K as well as the InSb array to 35 K by a mechanical refrigerator. We show the results of the background surface brightnesses and the limiting magnitudes at 3.3 and 3.67 μm measured at Sutherland, South Africa. We describe the on-going upgrade of this instrument, equipped with a 1024 × 1024 ALADDIN InSb science grade array. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献   

Geospatial Information and Environmental Isotopes for Hydrogeological Evaluation: Ras Alam El Rum,Northwestern Coast of Egypt     

Mohamed Yousif  Takashi Oguchi  Katsuro Anazawa  Takeshi Ohba 《Natural Resources Research》2014,23(4):423-445

The present study demonstrates the potential of the geospatial information as well as isotopes and chemical analyses to elucidate the hydrogeological setting of the study area. The main objective of this research is to identify factors affecting the occurrence and quality of groundwater in the study area. The Ras Alam El Rum is the pilot area chosen in the northwestern coast of Egypt to evaluate the carbonate aquifer with emphasis on the Middle Miocene aquifer, which has been explored recently. The average of annual precipitation and surface runoff amounts were estimated to indicate possibility of groundwater recharge, where the water-bearing rocks are mainly fractured. The isotope data indicate that the groundwater was derived from rainwater, the recharge source is local precipitation, and no indication of seawater intrusion was recorded. The salinity of the groundwater is attributed to interaction between the water and aquifer rocks represented by limestone, dolomitic limestone, and marl. The mineral indices obtained from the geochemical model reveal that the groundwater is over-saturated with aragonite, calcite, dolomite, strontianite, and barite. The hydrogeological evaluation of the study area led to recommendations to determine of the suitable areas for exploration of the Middle Miocene aquifer and to protect groundwater from deterioration.  相似文献   

Geochemical diversity in submarine HIMU basalts from Austral Islands, French Polynesia     

Takeshi Hanyu  Laure Dosso  Osamu Ishizuka  Kenichiro Tani  Barry B. Hanan  Claudia Adam  Shun’ichi Nakai  Ryoko Senda  Qing Chang  Yoshiyuki Tatsumi 《Contributions to Mineralogy and Petrology》2013,166(5):1285-1304

We present the first report of geochemical data for submarine basalts collected by a manned submersible from Rurutu, Tubuai, and Raivavae in the Austral Islands in the South Pacific, where subaerial basalts exhibit HIMU isotopic signatures with highly radiogenic Pb isotopic compositions. With the exception of one sample from Tubuai, the ⁴⁰Ar/³⁹Ar ages of the submarine basalts show no significant age gaps between the submarine and subaerial basalts, and the major element compositions are indistinguishable at each island. However, the variations in Pb, Sr, Nd, and Hf isotopic compositions in the submarine basalts are much larger than those previously reported in subaerial basalts. The submarine basalts with less-radiogenic Pb and radiogenic Nd and Hf isotopic compositions show systematically lower concentrations in highly incompatible elements than the typical HIMU basalts. These geochemical variations are best explained by a two-component mixing process in which the depleted asthenospheric mantle was entrained by the mantle plume from the HIMU reservoir during its upwelling, and the melts from the HIMU reservoir and depleted asthenospheric mantle were then mixed in various proportions. The present and compiled data demonstrate that the HIMU reservoir has a uniquely low ¹⁷⁶Hf/¹⁷⁷Hf decoupled from ¹⁴³Nd/¹⁴⁴Nd, suggesting that it was derived from an ancient subducted slab. Moreover, the Nd/Hf ratios of the HIMU basalts and curvilinear Nd–Hf isotopic mixing trend require higher Nd/Hf ratios for the melt from the HIMU reservoir than that from the depleted mantle component. Such elevated Nd/Hf ratios could reflect source enrichment by a subducted slab during reservoir formation.  相似文献   

Quantitative analysis of the geometry of submarine external levées     

Takeshi Nakajima  Benjamin C. Kneller 《Sedimentology》2013,60(4):877-910

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http://www.sciencedirect.com/science/article/pii/S1674987112001284     

Waclar Azeem Jadoon  Ryosuke Nakai  Takeshi Naganuma 《地学前缘(英文版)》2013,4(6):633-646

This study deals with the biogeography of Antarctic microflora （Antarctica acts as best model to study microbial biogeography） such as cyanobacteria and selected halophiles with special emphasis on Halomonas variabilis and Bacillus licheniformis.Halophiles are known to be resistant not only to salt stress,but also to extreme temperature,pressure,and aridity and they are capable of surviving in harsh environments such as polar regions,deep-sea habitats,and deserts.Many microbes are known to be resistant to hostile environmental conditions,and are capable of surviving in harsh environments.Our group has isolated 444 strains belonging to 28 genera of halophiles from various environments around the world.The 16S rRNA gene sequences revealed that many of the isolated strains from geographically distant habitats having different environmental conditions,were closely related to each other,with some strains possessing 100％ identical sequences.Organisms possessing survival mechanism such as spore formation are usually ubiquitous.The genus Halomonas is represented by potentially endemic strains and the ubiquitous H.variabilis,while spore-forming B.licheniformis showed cosmopolitan distribution.One potentially endemic （moderate endemicity that is regional and/or continental distribution） strain was reported from Syowa station,East Antarctica,and Mario Zucchelli station,West Antarctica,which are geographically separated by 3000 km.Moreover,15 strains having 100％ similarity with B.licheniformis were considered cosmopolitans.The results of this work provide support for the middle-ground model that some microbes have moderate endemicity and others have cosmopolitan distribution.These results will contribute to a greater understanding of microbial biogeography with special emphasis on Antarctica.  相似文献