Microbial Poly(L-Lactide)-Degrading Enzyme Induced by Amino Acids, Peptides, and Poly(L-Amino Acids)

Poly(L-lactide)(PLA)-degrading activities of a fungus, Tritirachium album, and two strains of actinomycetes,Lentzea waywayandensis and Amycolatopsis orientalis, were inducible by some proteins (poly-L-amino acid), peptides and amino acids. Extracellular PLA-degrading activity of the culture filtrates was detected when these strains grew in liquid basal medium containing 0.1% (w/v) of (poly-L-amino acids), peptides or amino acids as the enzyme inducer. In addition to PLA-degrading activity, succinyl-(L-alanyl-L-alanyl-L-alanine)-p-nitroanilide (Suc-(Ala)₃-pNA)-degrading activity was observed, implying that the enzymes produced were protease-type. The enzyme activities produced varied between different strains and different inducers. Silk fibroin was the best inducer for A. orientalis and that elastin was the best inducer for L. waywayandensis and T. album.     

Improved application of recombinant yeast assays on environmental samples by size exclusion chromatography

The utility of HPLC with a size exclusion chromatography (SEC) column for the fractionation of environmental samples was examined to expand the applicability of recombinant yeast assays (RYAs) for the measurement of estrogenic activity in environmental samples. The elution of steroidal hormone standards through SEC was tested, and river water and sediment samples were subjected to SEC fractionation. The retention times of all estrogen standards were longer than those of the major components with absorbance at 230 nm of the environmental sample matrix. The estrogenic activity of SEC fractions of environmental samples from highly polluted sites was measured using RYA and revealed the existence of estrogenic compounds that could not be detected or quantified in extracted samples before fractionation. The fractions from environmental samples that corresponded to the retention time of estrone, 17[small beta]-estradiol, and estriol were analyzed with LC/MS/MS. These three estrogens were separated into three different fractions, and the concentration of estrone coincided with the estrogenic activity of the fraction in which it was detected. The profile of estrogenic activity of SEC fractions indicated the molecular size of the estrogenic compounds and the yeast growth inhibitors in samples.     

Concentrations of polychlorinated dibenzo-p-dioxins, dibenzofurans, non-ortho polychlorinated biphenyls, and mono-ortho polychlorinated biphenyls in Japanese flounder, with reference to the relationship between body length and concentration

The concentrations of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), non-ortho polychlorinated biphenyls (non-ortho PCBs), and mono-ortho polychlorinated biphenyls (mono-ortho PCBs) in Japanese flounder (Paralichthys olivaceus, body length 10.4-36.6 cm) collected from Sendai Bay, Japan, were determined using high-resolution gas chromatography-mass spectrometry. The relationship between the concentrations of these compounds (dioxins) and the body length of the Japanese flounder was examined. The total PCDD and total PCDF concentrations did not correlate with body length (both r(2) < 0.1, both p > 0.05), whereas the total non-ortho PCB and total mono-ortho PCB (coplanar polychlorinated biphenyls, Co-PCBs) concentrations were significantly correlated (r(2)= 0.8, p < 0.05 and r(2)= 0.63, p < 0.05, respectively). The bioaccumulation properties of PCDD/Fs in Japanese flounder differed from those of Co-PCBs. Toxicity equivalency quotient (TEQ) values derived from the Co-PCBs made up 46.3%-63.7% of the total TEQ value for all the dioxins. Although the concentrations of non-ortho PCBs were lower than those of mono-ortho PCBs, the TEQ value for non-ortho PCBs was higher than that for mono-ortho PCBs. The TEQ value for non-ortho PCBs increased more with increasing body length than did the values for PCDDs, PCDFs, and mono-ortho PCBs. These results show that from the standpoint of risk management, non-ortho Co-PCBs are the most important of the dioxins in Japanese flounder.     

Influence of the Hydrothermal Pre-treatments on the Adsorption Characteristics of Activated Carbons from Woods

The hydrothermal treatments were conducted prior to the carbonization of oak woods and the obtained charcoals were activated using carbon dioxide or water vapor. The hydrothermal treatments brought about the elutions of acid-soluble lignin fractions as well as hemicellulose fractions accompanied with the decomposition of lignin carbohydrate complexes in the cell walls, which lowered not only the carbon yield of charcoal but also the crystal parameters for the carbon crystallites. However, the activated carbons (AC) produced via the hydrothermal pre-treatment showed superior adsorption properties especially for the adsorptions of 2-methylisoborneol and geosmin as compared with the untreated commercial AC. The hydrothermal treatments prior to the carbonization have some potential to increase the fractions of meso-pores effective for the adsorption of globular shaped molecules.     

Immobilization of B,F, Cr,and As in alkaline coal fly ash through an aging process with water

Fourteen different alkaline coal fly ashes (CFAs) were used for the experiment, in which each sample was mixed with water to be 28.6 % of water content (wt/wt) and aged for 1–4 weeks at 10–30 °C. This simple treatment is advantageous for decreases in water-soluble B, F, Cr, and As. Compared to non-aged CFAs, their water-soluble fractions remained 0.56–88 %, 21–85 %, 0.37–93 % and 2.6–88 %, respectively, after aging for a week at 20 °C, although the amounts of Cr and As released from some CFA samples increased. Considering the significant decrease in elution of sulfate, Ca and Al after aging, the immobilization, namely prevention of toxic element elution, could be related to formation of secondary minerals such as portlandite, gypsum and ettringite. Immobilization of B and Cr tends to proceed preferentially under colder conditions. Aging at higher temperatures enhances the leachability of Cr in some CFA samples. Contrary to the behavior of B and Cr, water-soluble F effectively decreases under warmer conditions.     

Pathway of 17��-estradiol degradation by Nitrosomonas europaea and reduction in 17��-estradiol-derived estrogenic activity

In recent years, natural and synthetic estrogens have been recognized as endocrine disruptors in aquatic organisms. Although natural and synthetic estrogens are known to be degraded by microbes, only limited information about their degradation pathways is available. Here, we studied the degradation pathways of a natural estrogen, 17β-estradiol, by the nitrifying microorganism Nitrosomonas europaea, and we determined whether the degradation products of 17β-estradiol had estrogenic activity. To identify the degradation products, we subjected the culture solution to solid-phase extraction, and the extract was analyzed by gas chromatography–mass spectrometry. The potential estrogenic activity of the degradation products was investigated by means of a yeast two-hybrid assay. 1,3,5(10),16-Estratetraen-3-ol (estratetraenol) was newly identified as a degradation intermediate produced by dehydration of 17β-estradiol. Estratetraenol was also degraded by N. europaea, and its degradation rate was faster than that of 17β-estradiol. The two-hybrid assay confirmed that estratetraenol acted as a ligand for the estrogen receptor; estratetraenol thus has potential estrogenic activity. N. europaea eliminated the estrogenic activity derived from 17β-estradiol. This paper is the first to report dehydration as a mechanism of microbial estrogen degradation.     

Transformations of selected pesticides in flooded rice-field soil — A review

Rice is mostly cultivated on soil held under flooded conditions during the growing season, where the plow layer differentiates into a thin oxidized surface layer and an underlying reduced layer. Under these conditions, certain pesticides undergo reductive transformations which are characteristic to rice fields and other anaerobic systems. Thus, lindane and pentachlorophenol are reductively dechlorinated into less toxic products, whereas, in highly reduced soils, thiobencarb is dechlorinated into a substance phytotoxic to rice plants. Nitrophenyl compounds, such as parathion and chlornitrofen, are converted into respective amino analogs, which are apt to remain as soil-bound residues. Transformation processes of these and several other environmentally important pesticides used in rice fields in the past and/or at present are reviewed.     

Estrogen content and relative performance of Japanese and British sewage treatment plants and their potential impact on endocrine disruption.

Both the UK and Japan are densely populated islands with relatively short rivers. Therefore, both countries are likely to be highly exposed to contaminants emanating from their human populations. This review considered how effective the different sewage treatment facilities of the two countries are at removing steroid estrogens from the effluent. The methods of estrogen analysis in sewage effluent, the number and importance of different sewage treatment types, and their apparent effectiveness at removing estrogens were all considered. In both countries, the activated sludge treatment was dominant in terms of people served and water discharged. The analytical techniques used by those studying estrogen concentrations in effluents in both countries were broadly similar. Activated sludge plant (ASP) effluent in the UK typically contained around 2 ng/L estradiol (E2) and 8 ng/L estrone (E1), while Japanese ASPs typically reported E2 as below detection, and 10 ng/L E1 in their effluents. When estrogenic bioassays were used in Japan, they typically record an estrogenic potency of 10 ng/L E2 equivalents. Even taking into account ethinylestradiol (EE2) (not found in Japanese effluents), the overall estrogenicity of British sewage effluents would appear to be the same as that of Japanese sewage effluents (around 10 ng/L E2 equivalents). This suggests that the ASPs serving the large urban communities in Japan and the UK would have effluent of similar estrogenic potencies. Less information is available about the more numerous biological (trickling) filter plants (BFP) in the UK and oxygen ditches (OD) in Japan which tend to serve smaller, more rural communities. The available data would suggest that the BFPs are significantly less efficient than the ODs at removing E1. This would suggest that in similar circumstances, British headwaters (where this sewage treatment plant (STP) type is often found) might be more at risk from endocrine disruption than their Japanese counterparts. Overall, the apparently higher incidence of endocrine disruption in British wild fish than in Japanese wild fish cannot be attributed to differences in the efficiency of their respective STPs.     

High (210)Po atmospheric deposition flux in the subtropical coastal area of Japan

Bulk atmospheric deposition fluxes of (210)Po and (210)Pb were measured at three coastal regions of Japan, the Pacific Ocean coastal area of the Japanese mainland (Odawa Bay), the Chinese continental side of Japanese coastal area (Tsuyazaki), and an isolated island near Okinawa (Akajima). Wet and dry fallout collectors were continuously deployed from September 1997 through August 1998 for periods of 3 to 31 days depending on the frequency of precipitation events. Annual (210)Pb deposition fluxes at Odawa Bay (35 degrees N 139 degrees E), Tsuyazaki (33 degrees N 130 degrees E) and Akajima (26 degrees N 127 degrees E) were 73.3+/-8.0, 197+/-35 and 78.5+/-8.0 Bqm(-2)y(-1), respectively. Higher (210)Pb deposition was observed at the Chinese continental side of Japanese coast than at the Pacific Ocean coastal site. The high (210)Pb atmospheric flux at the Chinese continental side coast was thought to be attributable to (222)Rn-rich air-mass transport from the Chinese continent during the winter monsoon. In contrast, the annual (210)Po deposition fluxes at the three study sites were 13.0+/-2.3 (Odawa Bay), 21.9+/-4.4 (Tsuyazaki) and 58.4+/-7.7 (Akajima)Bqm(-2)y(-1), respectively, indicating unusual high (210)Po deposition at Akajima during winter. Anomalous unsupported (210)Po input was observed during summer 1997, suggesting unknown source of (210)Po at this area.     

Genetic structure of rhinoceros auklets,Cerorhinca monocerata,breeding in British Columbia,Alaska, and Japan

Data from eight microsatellite markers screened in 246 rhinoceros auklets (Cerorhinca monocerata) from across the North Pacific revealed multiple genetic groups. The east (North America) to west (Japan) split was clearly evident in all analyses. Within the eastern Pacific, a minimum of three genetic groups are present. Surprisingly, rhinoceros auklets from Triangle Island, British Columbia, were genetically isolated from other nearby populations, including the breeding colony on Pine Island (~100 km to the east). A fourth genetic cluster (Chowiet Is) was detected using principal coordinate’s analysis; however, sample sizes were limited. Patterns of differentiation correspond to nonbreeding distributions with the eastern and western Pacific birds spending time off the west coast of North America and Japan, respectively, and may represent historical isolation in separate refugia during the Pleistocene glaciations. The patterns of genetic structure result from a combination of historical and contemporary factors influencing dispersal of rhinoceros auklets.