Spatial distribution of hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs) and organochlorines in bivalves from Japanese coastal waters.

In order to elucidate the spatial distribution of brominated flame retardants (BFRs) in the Japanese coastal environment, hexabromocyclododecanes (HBCDs), polybrominated diphenyl ethers (PBDEs) and organochlorines (OCs: PCBs, DDTs, CHLs, HCHs, HCB) were determined in bivalves (oysters and mussels) collected from Japanese coastal waters. HBCDs and PBDEs were detected in all samples analyzed. Concentration ranges of HBCDs were 12-5200 ng g(-1) lipid wt., followed by PCBs (20-3100 ng g(-1))>PBDEs (3.1-86 ng g(-1) lipid wt.). The highest concentration of HBCDs was found in the Osaka region. This result indicates that HBCDs are ubiquitous and predominant compounds in bivalves from the Japanese coastal waters. Since no species differences between oysters and mussels were observed for the bioaccumulation properties of HBCDs and PBDEs, oysters could be utilized for BFR contamination monitoring worldwide as an alternative to mussels. Global comparisons between oysters and mussels showed that HBCD concentrations in Japan are among the highest levels reported from Asia and Europe. Estimated dietary exposures of HBCDs and PBDEs through seafood were 0.45-34 ng kg body weight(-1)d(-1), and 0.054-6.8 ng kg body weight(-1)d(-1), respectively. These exposure levels were more than 1000 times lower than the lowest observable effects or no observable adverse effects levels for HBCDs and PBDEs, respectively.

Characterization of bradykinin-induced endothelium-independent contraction in equine basilar artery.

We investigated the effect of bradykinin (BK) on isolated equine basilar arterial rings with and without endothelium. BK induced concentration-dependent contraction of resting arterial rings and no relaxation when the rings were precontracted by prostaglandin F(2alpha). The maximal response and pD(2) value were 161.2 +/- 28.1% (to 60 mm KCl-induced contraction) and 8.24 +/- 0.25 respectively. The cumulative concentration-response curve for BK was not shifted to the right by des-Arg(9)-[Leu(8)]-BK (a B(1)-receptor antagonist), HOE140 (a B(2)-receptor antagonist) or NPC567 (another B(2)-receptor antagonist). In four of six basilar arteries, NPC567 induced concentration-dependent contraction. Indomethacin (a cyclooxygenase inhibitor), nordihydroguaiaretic acid (a lipoxygenase inhibitor), quinacrine (a phospholipase A(2) inhibitor), tetrodotoxin (a selective blocker of Na(+) channels), guanethidine (a nor-adrenergic neuron blocking drug), phentolamine (an alpha-adrenoceptor antagonist), Nomega-nitro-L-arginine (L-NNA, a nitric oxide (NO) synthase inhibitor) and endothelial denudation did not affect the BK-induced contraction. L-NNA and indomethacin induced contraction and relaxation under resting vascular tone respectively. These results suggest that endothelial cells are not involved in BK-induced contraction and that the contraction is not mediated via activation of known B(1) and B(2) receptors. Arachidonic acid metabolites and neurotransmitters like norepinephrine and NO might not play a role in BK-induced contraction in equine basilar artery.

A major quantitative trait locus controlling cadmium translocation in rice (Oryza sativa).

The trait of low cadmium (Cd) accumulation in brown rice (Oryza sativa) is important for food safety. An effective way to reduce Cd accumulation in the grain is to control Cd transfer from the roots to the shoots. Here, we investigated genotypic variation in the shoot Cd concentration among 146 accessions from a rice core collection and performed a quantitative trait locus (QTL) analysis to determine the loci controlling shoot Cd accumulation. Furthermore, we physiologically characterized the two accessions used for QTL analysis. Large genotypic variation (13-fold) in the shoot Cd concentration was found. A major QTL was detected on chromosome 11 using a F2 population derived from Badari Dhan (a high-Cd accession) and Shwe War (a low-Cd accession). This QTL explained 16.1% of the phenotypic variation in Cd accumulation. Furthermore, this QTL was confirmed by analysis of advanced progeny. Physiological studies showed that Badari Dhan and Shwe War did not differ in uptake of Cd by the roots, but differed greatly in the translocation of Cd from the roots to the shoots. Taken together, our findings suggest that the major QTL detected is responsible for the translocation of Cd from the roots to the shoots.

Variation in root-to-shoot translocation of cadmium and zinc among different accessions of the hyperaccumulators Thlaspi caerulescens and Thlaspi praecox.

Efficient root-to-shoot translocation is a key trait of the zinc/cadmium hyperaccumulators Thlaspi caerulescens and Thlaspi praecox, but the extent of variation among different accessions and the underlying mechanisms remain unclear. Root-to-shoot translocation of Cd and Zn and apoplastic bypass flow were determined in 10 accessions of T. caerulescens and one of T. praecox, using radiolabels (109)Cd and (65)Zn. Two contrasting accessions (Pr and Ga) of T. caerulescens were further characterized for TcHMA4 expression and metal compartmentation in roots. Root-to-shoot translocation of (109)Cd and (65)Zn after 1 d exposure varied 4.4 to 5-fold among the 11 accessions, with a significant correlation between the two metals, but no significant correlation with uptake or the apoplastic bypass flow. The F(2) progeny from a cross between accessions from Prayon, Belgium (Pr) and Ganges, France (Ga) showed a continuous phenotype pattern and transgression. There was no significant difference in the TcHMA4 expression in roots between Pr and Ga. Compartmentation analysis showed a higher percentage of (109)Cd sequestered in the root vacuoles of Ga than Pr, the former being less efficient in translocation than the latter. Substantial natural variation exists in the root-to-shoot translocation of Cd and Zn, and root vacuolar sequestration may be an important factor related to this variation.

Identification of two novel phytosiderophores secreted by perennial grasses.

It has been suggested that some perennial grasses secrete phytosiderophores in response to iron (Fe) deficiency, but the compounds have not been identified. Here, we identified and characterized the phytosiderophores secreted by two perennial grasses, Lolium perenne cv. Tove and Poa pratensis cv. Baron. Root exudates were collected from the roots of Fe-deficient grasses and then purified with various chromatographies. The structure of the purified compounds was determined using both nuclear magnetic resonance and fast atom bombardment mass spectrometry. Both species secreted phytosiderophores in response to Fe deficiency, and the amount of phytosiderophores secreted increased with the development of Fe deficiency. The type of phytosiderophores secreted differed with plant species; L. perenne cv. Tove secreted 3-epihydroxy-2'-deoxymugineic acid (epiHDMA), 2'-deoxymugineic acid (DMA) and an unknown compound, whereas P. pratensis cv. Baron secreted DMA, avenic acid A (AVA) and an unknown compound. Purification and subsequent analysis with nuclear magnetic resonance and mass led to identification of the two novel phytosiderophores; 3-hydroxy-2'-deoxymugineic acid (HDMA) from L. perenne, and 2'-hydroxyavenic acid A (HAVA) from P. pratensis. Both novel phytosiderophores have similar chelating activity to known phytosiderophores.

Global pollution monitoring of butyltin compounds using skipjack tuna as a bioindicator.

Butyltin compounds (BTs) including mono- (MBT), di- (DBT), tri-butyltin (TBT) and total tin (sigmaSn), were determined in the liver of skipjack tuna (Katsuwonus pelamis) collected from Asian offshore waters (off-Japan, the Japan Sea, off-Taiwan, the East China Sea, the South China Sea, off-Philippines, off-Indonesia, the Bay of Bengal), off-Seychelles, off-Brazil and open seas (the North Pacific). BTs were detected in all the skipjack tuna collected, suggesting widespread contamination of BTs even in offshore waters and open seas on a global scale. Considering specific accumulation, Sex-, body length- differences and migration of skipjack tuna did not seem to affect BT concentrations, indicating rapid reflection of the pollution levels in seawater where and when they were collected. Skipjack tuna is a suitable bioindicator for monitoring the global distribution of BTs in offshore waters and open seas. High concentrations of BTs were observed in skipjack tuna from offshore waters around Japan, a highly developed and industrialized region (up to 400 ng/g wet weight). Moreover skipjack tuna collected from offshore waters around Asian developing countries also revealed the levels comparable to those in Japan (up to 270 ng/g wet weight) which may be due to the recent improvement in economic status in Asian developing countries. High percentages (almost 90%) of BTs in total tin (sigmaSn: sum of inorganic tin+organic tin) were found in the liver of skipjack tuna from offshore waters around Asian developing countries. This finding suggests that the anthropogenic BTs represent the major source of Sn accumulation in skipjack tuna from these regions.

Global pollution monitoring of PCBs and organochlorine pesticides using skipjack tuna as a bioindicator.

Concentrations of organochlorines (OCs) representing persistent organic pollutants (POPs), such as polychlorinated biphenyls (PCBs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), chlordane compounds (CHLs), hexachlorocyclohexane isomers (HCHs), and hexachlorobenzene (HCB), were determined in the liver of skipjack tuna (Katsuwonus pelamis) collected from the offshore waters of various regions in the world (offshore waters around Japan, Taiwan, Philippines, Indonesia, Seychelles, and Brazil, and the Japan Sea, the East China Sea, the South China Sea, the Bay of Bengal, and the North Pacific Ocean). OCs were detected in livers of all of the skipjack tuna collected from the locations surveyed, supporting the thesis that there is widespread contamination of persistent OCs in the marine environment. Within a location, no significant relationship between growth-stage (body length and weight) and OC concentrations (lipid weight basis) was observed, and the OC residue levels were rather uniform among the individuals. Interestingly, the distribution of OC concentrations in skipjack tuna was similar to those in surface seawaters from which they were taken. These results suggest that OC concentrations in skipjack tuna could reflect the pollution levels in seawater from which they are collected and that this species is a suitable bioindicator for monitoring the global distribution of OCs in offshore waters and the open ocean. Concentrations of PCBs and CHLs in skipjack tuna were higher in offshore waters around Japan (up to 1100 and 250 ng/g lipid wt, respectively), suggesting the presence of sources of PCBs and CHLs in Japan. High concentrations of DDTs and HCHs were observed in samples from the Japan Sea, the East China Sea, the South China Sea, and the Bay of Bengal (up to 1300 and 22 ng/g lipid wt, respectively). This result suggests recent use of technical DDT and HCH for agricultural and/or public health purposes in Russia, China, India, and some other developing Asian countries. Relatively high concentrations of PCBs, CHLs, HCHs, and HCB were also observed in samples collected from some locations in the middle of the Pacific Ocean, indicating the expansion of OC contamination on a global scale. Considering these facts, continuous studies monitoring these compounds in offshore waters and the open seas, using skipjack tuna as a bioindicator, are needed to further understand the future trend of contamination.

Specific accumulation of polychlorinated biphenyls and organochlorine pesticides in Japanese common squid as a bioindicator.

Organochlorines (OCs) representing Persistent Organic Pollutants (POPs) such as PCBs (polychlorinated biphenyls), DDTs (DDT and its metabolites), CHLs (chlordane compounds), HCHs (hexachlorocyclohexane isomers) and HCB (hexachlorobenzene) were determined in the liver of Japanese common squid (Todarodes pacificus) collected from the waters around Japan (Japan Sea and western North Pacific Ocean). Among OCs concentrations, PCBs (upto 5600 ng/g lipid wt.) were the highest, and those of other OCs were in the order of DDT> CHLs > HCHs > HCB. Studies on growth trend and seasonal variation of OCs in this species suggest a rapid reflection of the pollution levels in seawater where and when they were collected, regardless of body-length and time of collection. These results indicate that Japanese common squid is a suitable bioindicator for monitoring OCs pollution in waters around Japan. With regard to the geographical distribution of OCs in this species collected from waters around Japan, OCs concentrations in specimens from Japan Sea were higher than those from the Pacific Ocean. This result might reflect some existing of local pollution sources of OCs around Japan Sea, and slower water exchange between Japan Sea and open ocean.

Organochlorine and butyltin residues in deep-sea organisms collected from the western North Pacific, off-Tohoku, Japan.

Organochlorine (OCs) and butyltin (BTs) residues were determined in deep-sea organisms collected from the western North Pacific, off-Tohoku, Japan. Among OCs, concentrations of polychlorinated biphenyls (PCBs) and DDTs (DDTs and its metabolites) were the highest in deep-sea organisms (maximum concentrations of 6,700 and 13,000 ng/g lipid wt, respectively). Chlordane compounds (CHLs) were the next most abundant OCs, and hexachlorocyclohexanes (HCHs) and hexachlorobenzene (HCB) were the lowest. BTs were also detected at maximum concentrations of 570 ng/g wet wt. Concentrations of PCBs, CHLs and BTs in deep-sea organisms collected from the western North Pacific, off-Tohoku, were generally lower than those in deep-sea and shallow water organisms from Japanese coastal waters. On the other hand, considerable variations in the concentrations of OCs were found among deep-sea organisms analyzed. Several carnivorous fishes such as snubnosed eel, lanternshark and grenadiers accumulated some OCs such as PCBs, DDTs and CHLs at high concentrations of up to a few microg/g levels. In addition, the residue pattern of OCs and BTs in fishes showed a specific trend according to the sampling depth; higher concentrations of PCBs, DDTs and CHLs and lower concentrations of HCHs, HCB and BTs were found in fishes collected from greater depth (approximately 1,000 m) compared to those from shallower waters. This trend is consistent with the results of our earlier study on mesopelagic myctophid fishes. Results of this study suggest vertical transport of hydrophobic OCs such as PCBs, DDTs and CHLs and its accumulation in benthic deep-sea organisms.

Anomalous magnetic-field dependence of positive ion mobility in normal liquid (3)He.

The positive ion mobility in normal liquid (3)He has been measured as a function of external magnetic field up to 15 T at temperatures down to 3 mK. At 3.2 mK, the field dependence is found to exhibit a pressure-dependent broad peak followed by a large decrease at pressures above 20 bars. On the other hand, at 20 mK, a monotonic decrease with increasing the magnetic field has been observed in the same pressure region. Possible origins for these anomalous behaviors are discussed.