Search

Lake Obuchi is on the Shimokita Peninsula, Aomori Prefecture, Japan, near several nuclear fuel-related facilities. The lake contains from oligohaline to polyhaline regions, and the salinity fluctuates greatly both spatially and temporally. This study examined the possible effect of salinity on biological concentrations of 137Cs in phytoplankton on the basis of a culture experiment using stable Cs and phytoplankton species isolated from the lake. In both Cyclotella and Skeletonema, the biological concentrations of Cs varied with salinity conditions, and a positive linear relation was found between maximum proliferation and biological concentrations of Cs. [ABSTRACT FROM AUTHOR]

In order to understand the role of nitrification and denitrification in the accumulation of nitrous oxide (N2O) in the hypolimnetic water of brackish Lake Nakaumi, the effects of dissolved oxygen (DO) concentration on these activities were investigated by incubation experiments. N2O was produced during the oxidation of NH4 + to NO2 − in nitrification and during the reduction of NO3 − to N2 in denitrification. N2O-producing activity by nitrification (N2ON) increased markedly with decreasing concentrations of DO. Low DO (10%–30% saturation) induced high N2ON. In contrast to nitrification, N2O-producing activity by denitrification (N2OD) decreased with decreasing concentrations of DO. Little N2O was accumulated during denitrification under low-level conditions of DO (10%–30%), because of further reduction of N2O to N2. It can therefore be assumed that N2O produced as the by-product of nitrification is concurrently reduced to N2 by denitrification under low-DO conditions. This would result in no substantial accumulation of N2O during active nitrification in the hypolimnetic water of Lake Nakaumi. [ABSTRACT FROM AUTHOR]

In Lake Shinji, Japan, periodic outbreaks of musty odour have occurred since mid-May 2007. Although the substance responsible for the odour was identified as geosmin, the odour-producing organism was unknown. We cultivated an axenic unialgal strain and determined that a species of Coelosphaerium (Synechococcales) was responsible for the production of geosmin in Lake Shinji. Our analysis was conducted using gas chromatography/mass spectrometry to determine the odorous compound. To determine the algae species, it was observed by optical microscopy to describe its morphological characteristics and the polymerase chain reaction was used to characterise the nucleotide sequence of the 16S rRNA gene and the 16S-23S rRNA internal transcribed spacer region. In addition, we explored the relationship between the number of cells of the Coelosphaerium sp. and the concentration of geosmin. In conclusion, geosmin, the cause of the musty odour in Lake Shinji in autumn 2009, was produced by Coelosphaerium sp., and to our knowledge, this is the first report of a geosmin-producing species in the family Coelosphaeriaceae. [ABSTRACT FROM AUTHOR]

We followed changes in the abundance of meso- and microzooplankton after an existing bottom hypoxia improved by the introduction of water with high oxygen content into the bottom. Mesozooplankton, calanoid copepod Acartia hudsonica showed ten times higher abundance under high oxygen condition at the bottom than under control where there was less oxygen at the bottom. On the other hand, during summer when microzooplankton such as rotifers and small cyclopoid species Oithona spp. were dominant, no difference in their distribution pattern and abundance was observed. Results have suggested that oxygen concentration at the bottom is one important factor determining the abundance and distribution of mesozooplankton even in local-scale probably by providing bottom refuge, but not for microzoooplankton. Since spring season is important for recruitment of many commercial fish juveniles, the distribution of oxygen in the lake seems very important for the fish stock in the lake.

Abstract background The effect of current therapies in improving the survival of lung cancer patients remains far from satisfactory. It is consequently desirable to find more appropriate therapeutic opportunities based on informed insights. A molecular pharmacological analysis was undertaken to design an improved chemotherapeutic strategy for advanced lung cancer. Methods We related the cytotoxic activity of each of commonly used anti-cancer agents (docetaxel, paclitaxel, gemcitabine, vinorelbine, 5-FU, SN38, cisplatin (CDDP), and carboplatin (CBDCA)) to corresponding expression pattern in each of the cell lines using a modified NCI program. Results We performed gene expression analysis in lung cancer cell lines using cDNA filter and high-density oligonucleotide arrays. We also examined the sensitivity of these cell lines to these drugs via MTT assay. To obtain our reproducible gene-drug sensitivity correlation data, we separately analyzed two sets of lung cancer cell lines, namely 10 and 19. In our gene-drug correlation analyses, gemcitabine consistently belonged to an isolated cluster in a reproducible fashion. On the other hand, docetaxel, paclitaxel, 5-FU, SN-38, CBDCA and CDDP were gathered together into one large cluster. Conclusion These results suggest that chemotherapy regimens including gemcitabine should be evaluated in second-line chemotherapy in cases where the first-line chemotherapy did not include this drug. Gene expression-drug sensitivity correlations, as provided by the NCI program, may yield improved therapeutic options for treatment of specific tumor types.