Studies on automated survey system of environmental chemicals by gas chromatography-mass spectrometry-computer II. Three dimensional mass chromatography

A three dimensional mass chromatography (TDMC), which is the extended method of mass chromatography, has been developed for the analysis of environmental chemicals. A considerable performance was suggested by the combination of TDMC to gas chromatography-mass spectrometry-computer system.     

Evidence for seasonal mate limitation in populations of an intertidal amphipod, Corophium volutator (Pallas)

Potential rates of reproduction (PRR) differ between the sexes of many animal species. Adult sex ratios together with PRR are expected to determine the operational sex ratio (OSR) defined as the ratio of fertilizable females to sexually active males at any given time. OSR is expected to determine the degree to which one sex competes for another—the limiting sex. We explored the potential for mate limitation in an intertidal amphipod, Corophium volutator (Pallas). Males have higher PRR than females, but males may be limiting because of extreme female-biased sex ratios observed in this species. Consistent with this idea, late season females were less likely to be ovigerous and had smaller size-specific clutches, both of which were associated with seasonal declines in availability of males of reproductive size. Seasonal changes in ovigery could not be explained by seasonal changes across sites in other factors (e.g., female body size or phenology of breeding). Smaller females were less likely to become ovigerous later in the season at three of four sites. Seasonal reductions in clutch size also occurred among small females expected to be reproducing for their first time. In complimentary laboratory experiments, reduced likelihood of ovigery and reduced fecundity occurred when the number of receptive females was increased relative to availability of a reproductively active male. Our results suggest male mate limitation can occur seasonally in this species and that male limitation is regionally widespread and may affect recruitment.     

Fluorescence and metal-ion recognition properties of acetylacetone-based ligands

A new acetylacetone-based ligand (Ligand 1) bearing pyrene unit was synthesized and the fluorescence and metal-ion recognition properties were investigated in the presence of a different metal ion in acetonitrile solution. The fluorescence emission of Ligand 1 was strongly quenched by complexation with Cu²⁺ while no significant change was observed in the presence of other metal ions. The metal-ion selectivity changed from Cu²⁺ to Ni²⁺ when glycine moiety (–NH–CH₂–CO–) was introduced into Ligand 1 as spacer. This result implies that hydrogen-bonding induced by the glycine moiety affects the binding ability of ligands to metal ions, resulting in change of the metal-ion selectivity.     

Antimony mobility in Japanese agricultural soils and the factors affecting antimony sorption behavior

The mobility of antimony (Sb) in Japanese agricultural soils was studied by radiotracer experiments using 124Sb tracer. The soil-solution distribution coefficients (Kd) of Sb were measured for 110 soil samples. These Kds ranged from 1 to 2065 L kg(-1); the geometric mean was 62 L kg(-1) excluding one extremely high value, 2065 L kg(-1). Experimental measurement of Kd showed a decrease with both increasing pH and increasing phosphate concentration. The latter suggested that one aspect of the Sb sorption phenomena in Japanese soil was influenced by specific adsorption of anions such as phosphate. However, other aspects could not be explained by this specific adsorption mechanism, because only 20-40% of soil-sorbed Sb could be extracted by phosphate solution.     

Prenatal interphase FISH diagnosis of PLP1 duplication associated with Pelizaeus–Merzbacher disease

A submicroscopic genomic duplication in Xq22.2 that contains the entire proteolipid protein 1 gene (PLP1) is responsible for the majority of Pelizaeus–Merzbacher disease (PMD) patients. We previously developed an interphase FISH assay to screen for PLP1 duplications in PMD patients using peripheral blood and lymphoblastoid cell lines. This assay has been utilized as a clinical diagnostic test in our cytogenetics laboratory. To expand usage of the interphase FISH assay to prenatal diagnosis of PLP1 duplications, we examined three PMD families with PLP1 duplications utilizing aminiotic fluid samples. In two families the FISH assay revealed fetuses with PLP1 duplications, whereas the other fetus showed a normal copy number of PLP1. Haplotype analyses, as well as an additional FISH analysis using postnatal blood samples, confirmed the results of the prenatal analyses. Our study demonstrates utility of the interphase FISH assay in the prenatal diagnosis of PLP1 duplications in PMD. Copyright © 2001 John Wiley & Sons, Ltd.     

Influence of americium-241 on the microbial population and biodegradation of organic waste

The present study investigated the influence of ²⁴¹Am on microbial growth and the degradation of organic waste. Leachate samples collected in a lysimeter were periodically analyzed for bacterial growth, under both aerobic and anaerobic conditions. ²⁴¹Am inhibited bacterial growth, and the degradation of organic matter was delayed in comparison with the control. Minimal inhibitory concentration assays and survival curves revealed that it inhibits the growth of Pseudomonas putida F1. The assay also revealed that ²⁴¹Am is more toxic than ²³⁸U, Zn²⁺ and Cd²⁺. This study further led to the finding of four new radionuclide-tolerant bacterial strains: Flavobacterium spp., Pseudomonas gladioli, Chryseobacterium indologenes and Ochrobactrum anthropi. The survival curves of P. gladioli, C. indologenes revealed that these bacteria are resistant to metal as consortia.     

Studies on automated survey system of environmental chemicals by gas chromatography-mass spectrometry-computer III. Construction of an automated survey system and its application

An automated survey system on the chemicals in environments by a gas chromatography-mass spectrometry-computer system has been constructed of Three Dimensional Mass Chromatography, Modified Probability Based Matching method, and Self Training Interpretive and Retrieval method. And it was applied to analyze environmental materials, with interesting results.     

Thymic involution produced by diesel exhaust particles and their constituents in mice

Epidemiological studies suggest that diesel exhaust particles (DEP) contribute to an increase in allergic diseases. To assess the effects of DEP on the central immune system, mice were exposed to DEP by intraperitoneal (IP) administration. Exposure to DEP resulted in severe thymic involution accompanied by a reduction in the number of thymocytes, especially in cortical CD4⁺CD8⁺ double positive and double negative subsets. Core carbon particles associated with a mixture of chemical compounds in DEP did not appear to be responsible for the DEP-induced thymic involution because carbon graphite does not affect neither the number nor the CD4/CD8 profile of thymocytes. Extraction of DEP by ether, acidic and basic solvents showed that several independent fractions including the neutral ether fraction, which contains polycyclic aromatic hydrocarbons (PAH), induced thymic involution. Among major PAH components of DEP, benzo[b]fluoranthene (BbF), benzo[a]pyrene (BaP), and benzo[k]fluoranthene (BkF) were very potent inducers of thymic involution at an ED50 of less than 100?ng per mouse body. Nonetheless, DEP treatment of mice with targeted disruption of genes encoding the aryl hydrocarbon receptor (AHR), AHR nuclear translocator (ARNT), or microsomal epoxide hydolase (mEH) indicated that DEP produced thymic involution even in the absence of PAH-induced AHR/ARNT signal transduction or mEH-mediated PAH catabolism. On the other hand, BaP-mediated thymic involution was completely dependent on AHR, partially dependent on ARNT in T cells, and independent of mEH. These results indicate that DEP-induced thymic involution is mediated both by PAH-AHR/ARNT-dependent and -independent mechanisms.     

A roadmap for the conservation of freshwater mussels in Europe

Europe has a long history of human pressure on freshwater ecosystems. As pressure continues to grow and new threats emerge, there is an urgent need for conservation of freshwater biodiversity and its ecosystem services. However, whilst some taxonomic groups, mainly vertebrates, have received a disproportionate amount of attention and funds, other groups remain largely off the public and scientific radar. Freshwater mussels (Bivalvia, Unionida) are an alarming example of this conservation bias and here we point out six conceptual areas that need immediate and long-term attention: knowledge, threats, socioeconomics, conservation, governance and education. The proposed roadmap aims to advance research, policy and education by identifying the most pressing priorities for the short- and long-term conservation of freshwater mussels across Europe.