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Aerosol samples, which are dust suspended in the atmosphere, were collected in Qira, Aksu, and Shapotou in 2001 and Qira, Dunhuang and Shapotou in 2002, which are located between north-western and central China, one of the possible source areas of Asian dust. Their chemical and isotopic compositions, mainly Sr and Nd isotopic compositions, in the total suspended particles (TSP) and finer fraction (ψ < 5 μm) in the TSP were analysed. There is a slight difference in the chemical compositions of TSP and the ψ < 5 μm fraction that can probably be attributed to the relative increase of silt and/or clay in the ψ < 5 μm fraction. 87Sr/86Sr ratios were 0.71770-0.72030 in the TSP and 0.72349-0.72737 in the ψ < 5 μm fraction over all sampling sites, although eNd(0) values were relatively constant, from −11.3 to −9.3. The isotopic characteristics due to the variation of particle size are clearly seen in Rb-Sr and Sr-Nd isotopic correlation diagrams, which are usefu1 aids to identify the sources of Asian dust. In addition to the possible isotopic change with particle size, results of Sr and Nd isotopic measurements suggest that the broad area from the north-western to the central part of China, i.e. from the Taklimakan Desert to the Central Loess Plateau, is characterized as a single possible source component of Asian dust. Clarifying the correlation between geochemical features and particle size is an important requirement that may allow the correlation of long-range transported Asian dust to possible source materials.

Aerosol sampling and meteorological observations were carried out from March 2001 to April 2004 at Aksu, in the northern part of the Taklimakan Desert in north-west China. There were three intensive observation periods (IOP): 11-24 April 2002, 16-26 March 2003 and 10-17 March 2004.The observed maximum concentration of total suspended particles (TSP) was 5.2 mg m−3 during the dust event of April 2003. Variations in the TSP and PM11 (panicles smaller than 11 μm) show that high atmospheric concentrations were observed during dust events that occurred mainly in spring and summer. According to the meteorological observations, dust storms or blowing sandldust occurred not only in spring, but also in summer and autumn, though floating dust occurred mainly in March and Apri1. The frequency of dust events was consisted with the results of dry deposition.During spring and summer, the size-distribution of aerosols is unimodal with a maximum in the range 3.3-7.0 μm, while in winter the size-distribution shows a bimodal pattern with two peaks; at 3.3-7.0 μm for soil particles and 0.65-1.1 μm for anthropogenic panicles. From the results of size distribution of soluble ion concentration, anthropogenic particles consist mainly of ammonium sulfate and ammonium nitrate, which result from coal combustion for heating during winter.Concerning chemical composition, aerosols from Aksu contain a significant amount of evaporate minerals such as calcium carbonate (calcite), sodium chloride (halite), and calcium sulfate (gypsum and anhydrite). These evaporates are common minerals in the saline soils which are widespread around observation site, and it is suggested that they are provided into atmosphere from the ground surface together with soil particles.Major element composition for aerosols in Aksu show a lower SiO2 content and higher FeO, K2O and MgO content compared with that for the saline soils (ψ < 125 μm), the loess deposits in the Tarim Basin and Central Loess Plateau, and Taklimakan Desert sands (ψ < 125 μm). This suggests that minerals rich in Fe, K and Mg, such as clay minerals and mica, come selectively from the soil surface into the atmosphere as mineral aerosols. This is because their particle size is generally smaller than that of quartz, the main constituent minerals in the soil.

Atmospheric aerosols have been collected at four sites around Japan during 2000. From systematically monitoring the major (Na, Mg, Al, K, Ca, and Fe) and trace (Rb and Sr) elements, along with the Sr isotope composition, we have tried to estimate the contribution of long-range-transported Asian dust (“Kosa”) to the atmospheric aerosols. The results are summarized as follows: (1) The concentration of each element in the aerosols increased during the “Kosa” period. The increase was particularly obvious in samples collected on 8 April 2000, when the “Kosa Phenomenon” was observed at all the sampling sites in Japan, 2 days after a very heavy dust storm had occurred in China. (2) The Rb–Sr isotopic diagram shows a two-component mixing relationship: one with a high 87Sr/86Sr ratio and a high 87Rb/86Sr ratio, and the other with a low 87Sr/86Sr ratio and a low 87Rb/86Sr ratio. There is a significant difference between that of the expected end member of the Asian dust and that of the reported Asian loess, which is thought to be the possible source of the components of the “Kosa”, although the lower component is consistent with the local component at Wako. (3) Plots of the 87Sr/86Sr ratio vs the Ca/Al and Sr/Al ratios support a two-component mixing suggested by the Rb–Sr systematics, and they indicate that the contributing continental soil components to the “Kosa” aerosols should be composed of the silicate fraction of Asian loess. (4) The discrepancy in the Rb–Sr systematics between the expected end member and the possible sources may be caused by the dissolution of the Ca-bearing minerals via long-range dust transport, or by a combination of source characteristics and grain size separation.

The cancer cells residing in the hypoxic layer are resistant to radiation and these are ones responsible for cancer recurrence after radiation therapy. One of the reasons why hypoxic cancer cells acquire radioresistance may be attributable to changes in the gene expression profile by the activation of hypoxia inducible factors (HIFs). However, the details underlying this process remain unknown. In this study, we investigated the effects of knockdown of HIF subunit genes to elucidate how HIF subunit genes may be involved in the radioresistance acquired by HeLa cells following exposure to a hypoxia mimic. Interestingly, HIF-1α and HIF-2α seemed mutually complementary for each other when either of them was suppressed. We thus suppressed the expression of both genes simultaneously. To do this, we developed a short hairpin RNA (shRNA) targeting a high homology region between HIF-1α and HIF-2α. It was shown that the expression of the shRNA effectively suppressed the acquisition of radioresistance following the hypoxia mimic. Moreover, it was confirmed that suppression of both subunits resulted in the downregulation of stem cell markers and the suppression of spheroid formation during the hypoxia mimicking-conditions. This shRNA-mediated knockdown method targeting a common region shared by a family of genes may offer a new candidate cancer treatment.

The 5.1-kb plasmid pAMalpha1delta2, a derivative of the 9.6-kb plasmid pAMalpha1 which is harbored by Enterococcus faecalis ATCC 14508, has a region necessary for replication in E. faecalis. The nucleotide sequence related to the replication region in pAMalpha1delta2 was determined and found to contain an open reading frame of 720-bp encoding a replication protein. The sequence showed 54.5 and 48.5% homology to those encoding the RepAs of plasmids pLA103 from Lactobacillus acidophilus and pFA3 from Neisseria gonorrhoeae, respectively. A recombinant 5.8-kb plasmid, pEFX6, which can be used as a shuttle vector between Escherichia coli and some strains of E. faecalis, was constructed by combining the tetracycline resistance gene of pAMalpha1delta2 and the replication regions of pAMalpha1delta2 and pUC18 for E. faecalis and E. coli, respectively. This shuttle vector was successfully used to clone and express the gelatinase gene from E. faecalis subsp. zymogenes IFO 3989 in E. faecalis C57, a strain showing no gelatinase activity.

This is the first report of the dissolved gas composition of a deep-sea venting hydrothermal system originating from arc volcanism; the origin of dissolved gases in hydrothermal fluids from the Suiyo seamount in the southern Izu-Bonin (Ogasawara) Arc is discussed on the basis of chemical and isotopic compositions. Twelve high-temperature (up to 310°C) fluid samples were collected from three vents of the hydrothermal system using the submersible Shinkai 2000. The average 3 He 4 He ratio of the dissolved He is 8.1 ( R R atm ), which is within the range of values reported for N-MORB. The CO 2 3 He ratio is 12 × 109, which is within the range of arc volcanic gas values. The δ13C values of CO2 and CH4 are −1 and −8.5‰ respectively, which is quite high compared with other subaerial arc volcanic gases and those from mid-ocean ridges. These results, which do not accord with those from subaerial volcanism, are unlikely to result from fractionation or addition of carbon sources during the fluid circulation, but are regarded as characteristic of the magma source of Suiyo Seamount. A simple mixing of 97% MORB mantle with 3% subducting slab explains well the composition of the helium and carbon in the parent magma.

The mitochondrial DNA was isolated from Aspergillus niger WU-2223L, a citric acid-production strain, and characterized by restriction-endonuclease mapping. Cloned fragments which covered the total range of the mitochondrial DNA were assembled and utilized to construct the restriction-endonuclease map for nine restriction enzymes. This map showed that the mitochondrial DNA was a circular molecule of 32.6 kb.

In genome sequencing project, we encounter the DNA regions that often contain stable secondary structure with high GC content. These regions are difficult to not only amplify by PCR for template preparations, but also determine the DNA sequences using standard Cycle sequencing (CS) method. Transcriptional sequencing (TS) is a unique DNA sequencing method using RNA polymerase, and is based on the principles of the chain-termination method, which is a powerful method to analyze GC-rich sequences. In this study, we examined the multiple displacement amplification (MDA) to overcome low efficiency of PCR amplification in GC-rich regions and subjected to TS reaction. Combination of MDA and TS (MDA-TS) was extremely successful with GC content ranging from 65% to 85%, which are difficult to analyze with PCR and CS. We also report plasmid vector, pTS1, which has the stronger T7 and T3 promoters than those of conventional vectors, and the sequence that decreases transcriptional efficiency was removed from its multiple cloning sites. pTS 1 resulted in the improved sequencing accuracy and reduced reaction time up to 5 min. These results showed that MDA-TS is a rapid and accurate method for the analysis of GC-rich templates.