Publications by authors named "Go Suzuki"

172 Publications

Investigation of novel brominated triazine-based flame retardant (TDBP-TAZTO) and its transformation products emitted from fire-retarded textile manufacturing facility and its downstream sewage treatment plant.

Sci Total Environ 2021 Jun 5;791:148233. Epub 2021 Jun 5.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, Japan.

Investigation of transformation products from novel flame retardants emitted throughout their life cycles is crucial for understanding and predicting environmental and human health risks posed by them during the material and product life cycle. Here, to understand more about the emission of TDBP-TAZTO to the environment, we investigated the presence of novel brominated triazine-based flame retardant 1,3,5-tris-(2,3-dibromopropyl)-1,3,5-triazine-2,4,6-trione (TDBP-TAZTO) and its transformation products in the effluent from a facility manufacturing fire-retarded textiles, and in the influent, effluent, and sludge of its closest downstream sewage treatment plant. To acquire mass spectra data of the transformation products in the influent, effluent, and sludge, non-target analysis was carried out by electrospray ionization-quadrupole time-of-flight-high-resolution mass spectrometry with liquid chromatography (LC-ESI-QTOF-HRMS). Then, the HaloSeeker 2.0 software was used to filter the mass spectrometry data for signals attributable to halogenated compounds. Combination of LC-ESI-QTOF-HRMS accurate mass measurements and HaloSeeker screening allowed us to determine the most probable elemental compositions and structures of 11 transformation products from TDBP-TAZTO and to construct a possible transformation pathway that included dehydrobromination, hydroxylation, and decarbonylation reactions. Based on analysis of the absolute intensities, we found that TDBP-TAZTO and its transformation products may not be easily removed by current sewage treatment plant process. There are increasing concerns about environmental contamination by TDBP-TAZTO and its transformation products different from the one which have previously been considered to be c-decaBDE and its lower brominated congeners. However, the present data suggest that concern is also warranted over the presence of TDBP-TAZTO and its transformation products in the environment. The present data will be useful for assessing, predicting, and understanding the environmental contamination and human health risks posed by TDBP-TAZTO, and for considering appropriate measures to control the emission of TDBP-TAZTO and its transformation products during product life cycles.
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http://dx.doi.org/10.1016/j.scitotenv.2021.148233DOI Listing
June 2021

Behavioral and Histopathological Impairments Caused by Topical Exposure of the Rat Brain to Mild-Impulse Laser-Induced Shock Waves: Impulse Dependency.

Front Neurol 2021 21;12:621546. Epub 2021 May 21.

Division of Bioinformation and Therapeutic Systems, National Defense Medical College Research Institute, Tokorozawa, Japan.

Although an enormous number of animal studies on blast-induced traumatic brain injury (bTBI) have been conducted, there still remain many uncertain issues in its neuropathology and mechanisms. This is partially due to the complex and hence difficult experimental environment settings, e.g., to minimize the effects of blast winds (tertiary mechanism) and to separate the effects of brain exposure and torso exposure. Since a laser-induced shock wave (LISW) is free from dynamic pressure and its energy is spatially well confined, the effects of pure shock wave exposure (primary mechanism) solely on the brain can be examined by using an LISW. In this study, we applied a set of four LISWs in the impulse range of 15-71 Pa·s to the rat brain through the intact scalp and skull; the interval between each exposure was ~5 s. For the rats, we conducted locomotor activity, elevated plus maze and forced swimming tests. Axonal injury in the brain was also examined by histological analysis using Bodian silver staining. Only the rats with exposure at higher impulses of 54 and 71 Pa·s showed significantly lower spontaneous movements at 1 and 2 days post-exposure by the locomotor activity test, but after 3 days post-exposure, they had recovered. At 7 days post-exposure, however, these rats (54 and 71 Pa·s) showed significantly higher levels of anxiety-related and depression-like behaviors by the elevated plus maze test and forced swimming test, respectively. To the best of the authors' knowledge, there have been few studies in which a rat model showed both anxiety-related and depression-like behaviors caused by blast or shock wave exposure. At that time point (7 days post-exposure), histological analysis showed significant decreases in axonal density in the cingulum bundle and corpus callosum in impulse-dependent manners; axons in the cingulum bundle were found to be more affected by a shock wave. Correlation analysis showed a statistically significant correlation between the depression like-behavior and axonal density reduction in the cingulum bundle. The results demonstrated the dependence of behavior deficits and axonal injury on the shock wave impulse loaded on the brain.
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http://dx.doi.org/10.3389/fneur.2021.621546DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8177106PMC
May 2021

Can Acropora tenuis larvae attract native Symbiodiniaceae cells by green fluorescence at the initial establishment of symbiosis?

PLoS One 2021 1;16(6):e0252514. Epub 2021 Jun 1.

Fisheries Technology Institute, Japan Fisheries Research and Education Agency, Ishigaki, Okinawa, Japan.

Most corals acquire symbiodiniacean symbionts from the surrounding environment to initiate symbiosis. The cell densities of Symbiodiniaceae in the environment are usually low, and mechanisms may exist by which new coral generations attract suitable endosymbionts. Phototaxis of suitable symbiodiniacean cells toward green fluorescence in corals has been proposed as one such mechanism. In the present study, we observed the phototaxis action wavelength of various strains of Symbiodiniaceae and the fluorescence spectra of aposymbiotic Acropora tenuis larvae at the time of endosymbiont uptake. The phototaxis patterns varied among the Symbiodiniaceae species and "native" endosymbionts-commonly found in Acropora juveniles present in natural environments; that is, Symbiodinium microadriaticum was attracted to blue light rather than to green light. Another native endosymbiont, Durusdinium trenchii, showed no phototaxis specific to any wavelength. Although the larvae exhibited green and broad orange fluorescence under blue-violet excitation light, the maximum green fluorescence peak did not coincide with that of the phototaxis action spectrum of S. microadriaticum. Rather, around the peak wavelength of larval green fluorescence, this native endosymbiont showed slightly negative phototaxis, suggesting that the green fluorescence of A. tenuis larvae may not play a role in the initial attraction of native endosymbionts. Conversely, broad blue larval fluorescence under UV-A excitation covered the maximum phototaxis action wavelength of S. microadriaticum. We also conducted infection tests using native endosymbionts and aposymbiotic larvae under red LED light that does not excite visible larval fluorescence. Almost all larvae failed to acquire S. microadriaticum cells, whereas D. trenchii cells were acquired by larvae even under red illumination. Thus, attraction mechanisms other than visible fluorescence might exist, at least in the case of D. trenchii. Our results suggest that further investigation and discussion, not limited to green fluorescence, would be required to elucidate the initial attraction mechanisms.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0252514PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8168901PMC
June 2021

Characterization of unsubstituted and methylated polycyclic aromatic hydrocarbons in settled dust: Combination of instrumental analysis and in vitro reporter gene assays and implications for cancer risk assessment.

Sci Total Environ 2021 Sep 18;788:147821. Epub 2021 May 18.

Center of Advanced Technology for the Environment (CATE), Graduate School of Agriculture, Ehime University, 3-5-7 Tarumi, Matsuyama 790-8566, Japan. Electronic address:

Concentrations of 34 unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) and AhR-mediated activities in settled dust samples were determined by a combination of gas chromatography-mass spectrometry and an in vitro reporter gene assay (PAH-CALUX). The levels of Σ34PAHs and bioassay-derived benzo[a]pyrene equivalents (CALUX BaP-EQs) were significantly higher in workplace dust from informal end-of-life vehicle dismantling workshops than in common house dust and road dust. In all the samples, the theoretical BaP-EQs of PAHs (calculated using PAH-CALUX relative potencies) accounted for 28 ± 19% of the CALUX BaP-EQs, suggesting significant contribution of aryl hydrocarbon receptor (AhR) agonists and/or mixture effects. Interestingly, the bioassay-derived BaP-EQs in these samples were significantly correlated with not only unsubstituted PAHs with known carcinogenic potencies but also many Me-PAHs, which should be included in future monitoring and toxicity tests. The bioassay responses of many sample extracts were substantially reduced but not suppressed with sulfuric acid treatment, indicating contribution of persistent AhR agonists. Cancer risk assessment based on the CALUX BaP-EQs has revealed unacceptable level of risk in many cases. The application of bioassay-derived BaP-EQs may reduce underestimation in environmental management and risk evaluation regarding PAHs and their derivatives (notably Me-PAHs), suggesting a consideration of using in vitro toxic activity instead of conventional chemical-specific approach in such assessment practices.
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http://dx.doi.org/10.1016/j.scitotenv.2021.147821DOI Listing
September 2021

Polycyclic aromatic hydrocarbons in airborne particulate matter samples from Hanoi, Vietnam: Particle size distribution, aryl hydrocarbon ligand receptor activity, and implication for cancer risk assessment.

Chemosphere 2021 Apr 30;280:130720. Epub 2021 Apr 30.

Centre for Environmental Technology and Sustainable Development (CETASD), University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, 11400, Viet Nam. Electronic address:

Concentrations and profiles of unsubstituted and methylated polycyclic aromatic hydrocarbons (PAHs and Me-PAHs) were analyzed in airborne particulate matter (PM) samples collected from high-traffic roads in Hanoi urban area. Levels of PAHs and Me-PAHs ranged from 210 to 660 (average 420) ng/m in total PM, and these pollutants were mainly associated with fine particles (PM) rather than coarser ones (PM and PM). Proportions of high-molecular-weight compounds (i.e., 5- and 6-ring) increased with decreasing particle size. Benzo[b+k]fluoranthene, indeno[1,2,3-cd]pyrene, and benzo[ghi]perylene were the most predominant compounds in the PM samples. In all the samples, Me-PAHs were less abundant than unsubstituted PAHs. The PAH-CALUX assays were applied to evaluate aryl hydrocarbon receptor (AhR) ligand activities in crude extracts and different fractions from the PM samples. Benzo[a]pyrene equivalents (BaP-EQs) derived by the PAH-CALUX assays for low polar fractions (mainly PAHs and Me-PAHs) ranged from 300 to 840 ng/m, which were more consistent with theoretical values derived by using PAH-CALUX relative potencies (270-710 ng/m) rather than conventional toxic equivalency factor-based values (22-69 ng/m). Concentrations of PAHs and Me-PAHs highly correlated with bioassay-derived BaP-EQs. AhR-mediated activities of more polar compounds and interaction effects between PAH-related compounds were observed. By using PAH-CALUX BaP-EQs, the ILCR values ranged from 1.0 × 10 to 2.8 × 10 for adults and from 6.4 × 10 to 1.8 × 10 for children. Underestimation of cancer risk can be eliminated by using effect-directed method (e.g., PAH-CALUX) rather than chemical-specific approach.
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http://dx.doi.org/10.1016/j.chemosphere.2021.130720DOI Listing
April 2021

-Acetyl-d-Glucosamine-Binding Lectin in Attracts Specific Symbiodiniaceae Cell Culture Strains.

Mar Drugs 2021 Mar 11;19(3). Epub 2021 Mar 11.

School of Marine Biosciences, Kitasato University, 1-15-1 Kitasato, Minami, Sagamihara, Kanagawa 252-0373, Japan.

Many corals establish symbiosis with Symbiodiniaceae cells from surrounding environments, but very few Symbiodiniaceae cells exist in the water column. Given that the -acetyl-d-glucosamine-binding lectin ActL attracts Symbiodiniaceae cells, we hypothesized that corals must attract Symbiodiniaceae cells using ActL to acquire them. Anti-ActL antibody inhibited acquisition of Symbiodiniaceae cells, and rearing seawater for juvenile contained ActL, suggesting that juvenile discharge ActL to attract these cells. Among eight Symbiodiniaceae cultured strains, ActL attracted NBRC102920 () most strongly followed by CS-161 (), CCMP2556 (), and CCMP1633 ( sp.); however, it did not attract GTP-A6-Sy (), CCMP421 (), FKM0207 ( sp.), and CS-156 ( sp.). Juvenile polyps of acquired limited Symbiodiniaceae cell strains, and the number of acquired Symbiodiniaceae cells in a polyp also differed from each other. The number of Symbiodiniaceae cells acquired by juvenile polyps of was correlated with the ActL chemotactic activity. Thus, ActL could be used to attract select Symbiodiniaceae cells and help Symbiodiniaceae cell acquisition in juvenile polyps of , facilitating establishment of symbiosis between and Symbiodiniaceae cells.
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http://dx.doi.org/10.3390/md19030146DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8002028PMC
March 2021

Rice MEDIATOR25, OsMED25, is an essential subunit for jasmonate-mediated root development and OsMYC2-mediated leaf senescence.

Plant Sci 2021 May 19;306:110853. Epub 2021 Feb 19.

Plant Genome and Resource Research Center, Faculty of Agriculture, Kagawa University, Miki, Kagawa, 761-0795, Japan. Electronic address:

The Mediator multiprotein complex acts as a universal adaptor between transcription factors (TFs) and RNA polymerase II. MEDIATOR25 (MED25) has an important role in jasmonic acid (JA) signaling in Arabidopsis. However, no research has been conducted on the role of MED25 in JA signaling in rice, which is one of the most important food crops globally and is a model plant for molecular studies in other monocotyledonous species. In the present study, we isolated the loss-of function mutant of MED25, osmed25, through the map-based cloning and phenotypic complementation analysis by the introduction of OsMED25 and investigated the role of OsMED25 in JA signaling in rice. The osmed25 mutants had longer primary (seminal) roots than those of the wild-type (WT) and exhibited JA-insensitive phenotypes. S-type lateral root densities in osmed25 mutants were lower than those in the WT, whereas L-type lateral root densities in osmed25 mutants were higher than those in the WT. Furthermore, the osmed25 mutants retarded JA-regulated leaf senescence under dark-induced senescence. Mutated osmed25 protein could not interact with OsMYC2, which is a positive TF in JA signaling in rice. The expression of JA-responsive senescence-associated genes was not upregulated in response to JA in the osmed25 mutants. The results suggest that OsMED25 participates in JA-mediated root development and OsMYC2-mediated leaf senescence in rice.
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http://dx.doi.org/10.1016/j.plantsci.2021.110853DOI Listing
May 2021

Unique environmental Symbiodiniaceae diversity at an isolated island in the northwestern Pacific.

Mol Phylogenet Evol 2021 Aug 19;161:107158. Epub 2021 Mar 19.

Sesoko Station, Tropical Biosphere Research Center, University of the Ryukyus, 3422 Sesoko, Motobu, Okinawa 905-0227, Japan.

Dinoflagellates in the family Symbiodiniaceae are intensively investigated as algal symbionts of corals and other invertebrates, underpinning coral reef ecosystems as primary producers. Diversity, including regional diversification, of free-living communities is less studied. In this study, an environmental Symbiodiniaceae community at an isolated island, Okinotori Island, Japan, was investigated to determine whether the community is endemic or common with other locations near continents and major ocean currents. Symbiotic algae in common corals at the island were the same type as those of the corals from other Japanese waters. In the environmental samples, genera Symbiodinium (formerly clade A), Cladocopium (clade C), Durusdinium (clade D), and clades F (including Freudenthalidium), G, and I, were identified through analysis of internal transcribed spacer region 2 of nuclear ribosomal RNA gene (ITS2) sequences. Interestingly, some sequences found were genetically different from those of previously reported genera/clades. These unknown sequences were genetically included in the Symbiodiniaceae linage, but they were differentiated from the previously known nine clades. The sequences formed a cluster in the phylogenetic tree based on 28S nrDNA. These sequences were thus considered members of a novel clade in the family (clade J). In total, 120 kinds of ITS2 sequences were produced; while 10 were identical to previously reported sequences, the majority were highly divergent. These genetically unique Symbiodiniaceae types, including novel clade J, may have evolved in isolation and reflect the environmental characteristics of the Okinotori Island.
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http://dx.doi.org/10.1016/j.ympev.2021.107158DOI Listing
August 2021

Comprehensive screening of polybromochlorodibenzo-p-dioxins, dibenzofurans as mixed halogenated compounds in wastewater samples from industrial facilities by GC×GC/ToFMS and post-data processing.

Chemosphere 2021 Aug 24;276:130085. Epub 2021 Feb 24.

National Institute for Environmental Studies, Onogawa 16-2, Tsukuba, Ibaraki, 305-8506, Japan.

An enormous number of pollutants must be investigated to be able to understand which types threaten human health and environmental biota. In this study, we propose a workflow for screening polybromochlorodibenzo-p-dioxins and dibenzofurans (PBCDD/Fs), which are compounds that have thousands of isomers and congeners, by combining measurement of a sample without any in-laboratory-cleanup with the results of comprehensive two-dimensional gas chromatography/time-of-flight mass spectrometry and post-data processing. This process can be regarded as "in silico sample cleanup." The post-data processing stage comprises two methods in which the extracted mass spectra are matched to exact mass and isotopic ratios specified as formulae and filtering via mass deficiency. We applied this workflow to wastewater samples from industrial facilities to identify mixtures of halogenated dioxins. As a result, it was estimated that dioxins in an absolute quantity of 10-500 pg could be detected with sufficient accuracy by recovery testing of a standard mixture against sample crude extracts. Tri- to octa-halogenated dioxins were detected in 8 of 13 samples. Leachate from an industrial landfill was found to contain relatively large numbers of PBCDD/Fs, and several congeners were found in wastewater from an industrial fabric facility that handles decabromodiphenyl ether. The workflow, including the post-data processing method developed and applied in this study, has the advantage that additional identifications can be performed at any time from a single set of measurement data. This also enables the screening of substances that have thousands of homologous isomers, such as chlorinated and brominated dioxins, as well as other non-halogenated compounds.
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http://dx.doi.org/10.1016/j.chemosphere.2021.130085DOI Listing
August 2021

Source contributions to multiple toxic potentials of atmospheric organic aerosols.

Sci Total Environ 2021 Jun 4;773:145614. Epub 2021 Feb 4.

National Institute for Environmental Studies, Tsukuba, Japan.

Fine particulate matter (PM) in the atmosphere is of high priority for air quality management efforts to address adverse health effects in human. We believe that emission control policies, which are traditionally guided by source contributions to PM mass, should also consider source contributions to PM health effects or toxicity. In this study, we estimated source contributions to the toxic potentials of organic aerosols (OA) as measured by a series of chemical and in-vitro biological assays and chemical mass balance model. We selected secondary organic aerosols (SOA), vehicles, biomass open burning, and cooking as possible important OA sources. Fine particulate matter samples from these sources and parallel atmospheric samples from diverse locations and seasons in East Asia were collected for the study. The source and atmospheric samples were analyzed for chemical compositions and toxic potentials, i.e. oxidative potential, inflammatory potential, aryl hydrocarbon receptor (AhR) agonist activity, and DNA-damage, were measured. The toxic potentials per organic carbon (OC) differed greatly among source and ambient particulate samples. The source contributions to oxidative and inflammatory potentials were dominated by naphthalene-derived SOA (NapSOA), followed by open burning and vehicle exhaust. The AhR activity was dominated by open burning, followed by vehicle exhaust and NapSOA. The DNA damage was dominated by vehicle exhaust, followed by open burning. Cooking and biogenic SOA had smaller contributions to all the toxic potentials. Regarding atmospheric OA, urban and roadside samples showed stronger toxic potentials per OC. The toxic potentials of remote samples in summer were consistently very weak, suggesting that atmospheric aging over a long time decreased the toxicity. The toxic potentials of the samples from the forest and the experimentally generated biogenic SOA were low, suggesting that toxicity of biogenic primary and secondary particles is relatively low.
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http://dx.doi.org/10.1016/j.scitotenv.2021.145614DOI Listing
June 2021

Emission of Dioxin-like Compounds and Flame Retardants from Commercial Facilities Handling Deca-BDE and Their Downstream Sewage Treatment Plants.

Environ Sci Technol 2021 02 14;55(4):2324-2335. Epub 2021 Jan 14.

Environment Preservation Research Center, Kyoto University, Kyoto 606-8501, Japan.

Commercial mixtures of decabromodiphenyl ether (deca-BDE), a brominated flame retardant, contain not only polybrominated diphenyl ethers (PBDEs, mainly BDE-209) as the main component but also dioxin-like compounds (DLCs) such as polybrominated dibenzofurans (PBDFs). Deca-BDE handling facilities (DHFs) and sewage treatment plants receiving effluent from DHFs are point sources of DLC and flame retardant (FR) pollution. Here, we examined their emission in Japan. For DHF effluents, DLCs detected by the dioxin-responsive chemically activated luciferase expression (DR-CALUX) assay were 1.3-890 pg TCDD-EQ/L (median 46 pg TCDD-EQ/L), while PBDEs and other FRs were <2.0-110,000 ng/L (610 ng/L) and 150-4,800,000 ng/L (41,000 ng/L). Risk quotients based on predicted no-effect concentrations suggested that DLCs, decabromodiphenyl ethane (DBDPE), tris(2,3-dibromopropyl) isocyanurate (TDBP-TAZTO), and bisphenol A bis(diphenyl phosphate) (BPA-BDPP) present significant risks for aquatic organisms. The concentrations of PBDFs, which are impurities in deca-BDE, were expected to decrease with the inclusion of deca-BDE in the Stockholm Convention list of persistent organic pollutants (May 2017). However, DLCs other than PBDFs and alternative FRs such as DBDPE, TDBP-TAZTO, and BPA-BDPP are likely still discharged. Additional findings indicate that strong (e.g., DLCs, DBDPE, and BPA-BDPP), but not weak (e.g., TDBP-TAZTO), hydrophobic compounds are sufficiently removed by current wastewater treatment processes in Japan.
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http://dx.doi.org/10.1021/acs.est.0c06359DOI Listing
February 2021

Inhalation bioaccessibility and health risk assessment of flame retardants in indoor dust from Vietnamese e-waste-dismantling workshops.

Sci Total Environ 2021 Mar 9;760:143862. Epub 2020 Dec 9.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan.

Although bioaccessibility testing is applied worldwide for appropriate chemical risk assessment, few studies have focused on the bioaccessibility of flame retardants (FRs), especially inhalation exposure. This study assessed inhalation exposure to FRs in indoor dust by workers at e-waste-dismantling workshops in northern Vietnam, by using modified simulated epithelial lung fluid (SELF) and artificial lysosomal fluid (ALF). The average mass concentrations of FRs were 130,000 ng/g for workplace dust (n = 3), 140,000 ng/g for floor dust (n = 3), and 74,000 ng/g for settled dust (n = 2), whereas the average bioaccessible concentrations of FRs were 1900, 1400, and 270 ng/g in the SELF condition and 2600, 770, and 490 ng/g in the ALF condition, respectively. Results clearly indicate that the bioaccessible concentrations of FRs are markedly lower than their mass concentrations. Tris(2-chloroethyl) phosphate (TCEP, ~19%), tris(2-chloroisopropyl) phosphate (TCIPP, ~35%), and tris(1,3-dichloroisopropyl) phosphate (TDCIPP, ~22%) showed comparably high bioaccessibility in both SELF and ALF conditions. In contrast, the bioaccessibility of tetrabromobisphenol A (TBBPA, ~20%) was high in the SELF condition, but not in the ALF condition. With regard to the test compounds' physicochemical properties, the inhalation bioaccessibility of FRs in both conditions increased as molecular weight or octanol-water partition coefficient decreased, and it decreased as water solubility decreased. Health risk assessment clearly indicated that the hazard quotient of FRs via inhalation exposure for workers in the e-waste-dismantling workshops was less than 1, suggesting that the inhalation exposure to FRs during indoor dismantling of e-waste at this site was negligible based on the current methodology of non-cancer health risk assessment used in this study.
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http://dx.doi.org/10.1016/j.scitotenv.2020.143862DOI Listing
March 2021

Fecal pellets of giant clams as a route for transporting Symbiodiniaceae to corals.

PLoS One 2020 16;15(12):e0243087. Epub 2020 Dec 16.

Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama, Higashi-Hiroshima, Hiroshima, Japan.

Because more than 80% of species of gamete-spawning corals, including most Acroporidae species, do not inherit Symbiodiniaceae from their parents, they must acquire symbiont cells from sources in their environment. To determine whether photosynthetically competent Symbiodiniaceae expelled as fecal pellets from giant clams are capable of colonizing corals, we conducted laboratory experiments in which planula larvae of Acropora tenuis were inoculated with the cells in fecal pellets obtained from Tridacna crocea. T. crocea fecal pellets were administered once a day, and three days later, cells of Symbiodiniaceae from the fecal pellets had been taken up by the coral larvae. T. crocea fecal pellets were not supplied from the 4th day until the 8th day, and the cell densities in the larvae increased until the 8th day, which indicated the successful colonization by Symbiodiniaceae. The control group exhibited the highest mean percentage of larvae (100%) that were successfully colonized by culture strains of Symbiodiniaceae, and larvae inoculated with fecal pellets reached a colonization percentage of 66.7 ~ 96.7% on the 8th day. The highest colonization rate was achieved with the fecal pellets containing cells with high photosynthetic competency (Fv/Fm). Interestingly, the genetic composition of Symbiodiniaceae in the larvae retrieved on the 8th day differed from that in the fecal pellets and showed exclusive domination of the genus Symbiodinium. A minor but significant population of the genus Cladocopium in the fecal pellets was not inherited by the larvae. These experiments provided the first demonstration that the Symbiodiniaceae from tridacnine clams provided via fecal pellets can colonize and even proliferate in coral larvae.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0243087PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7743926PMC
January 2021

Whole-Genome Transcriptome Analyses of Native Symbionts Reveal Host Coral Genomic Novelties for Establishing Coral-Algae Symbioses.

Genome Biol Evol 2021 01;13(1)

Atmosphere and Ocean Research Institute, The University of Tokyo, Kashiwa, Chiba, Japan.

Reef-building corals and photosynthetic, endosymbiotic algae of the family Symbiodiniaceae establish mutualistic relationships that are fundamental to coral biology, enabling coral reefs to support a vast diversity of marine species. Although numerous types of Symbiodiniaceae occur in coral reef environments, Acropora corals select specific types in early life stages. In order to study molecular mechanisms of coral-algal symbioses occurring in nature, we performed whole-genome transcriptomic analyses of Acropora tenuis larvae inoculated with Symbiodinium microadriaticum strains isolated from an Acropora recruit. In order to identify genes specifically involved in symbioses with native symbionts in early life stages, we also investigated transcriptomic responses of Acropora larvae exposed to closely related, nonsymbiotic, and occasionally symbiotic Symbiodinium strains. We found that the number of differentially expressed genes was largest when larvae acquired native symbionts. Repertoires of differentially expressed genes indicated that corals reduced amino acid, sugar, and lipid metabolism, such that metabolic enzymes performing these functions were derived primarily from S. microadriaticum rather than from A. tenuis. Upregulated gene expression of transporters for those metabolites occurred only when coral larvae acquired their natural symbionts, suggesting active utilization of native symbionts by host corals. We also discovered that in Acropora, genes for sugar and amino acid transporters, prosaposin-like, and Notch ligand-like, were upregulated only in response to native symbionts, and included tandemly duplicated genes. Gene duplications in coral genomes may have been essential to establish genomic novelties for coral-algae symbiosis.
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http://dx.doi.org/10.1093/gbe/evaa240DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7850063PMC
January 2021

Double-Locking Mechanism of Self-Compatibility in : The Synergistic Effect of Transcriptional Depression and Disruption of Coding Region in the Male Specificity Gene.

Front Plant Sci 2020 11;11:576140. Epub 2020 Sep 11.

Graduate School of Life Sciences, Tohoku University, Sendai, Japan.

Self-compatibility in represents the relatively recent disruption of ancestral obligate cross pollination, recognized as one of the prevalent evolutionary pathways in flowering plants, as noted by Darwin. Our previous study found that inversion of the male specificity gene (/) disrupted self-incompatibility, which was restored by overexpressing the with the reversed inversion. However, in has other mutations aside from the pivotal inversion, in both promoter and coding regions, with probable effects on transcriptional regulation. To examine the functional consequences of these mutations, we conducted reciprocal introductions of native promoters and downstream sequences from orthologous loci of self-compatible and self-incompatible . Use of this inter-species pair enabled us to expand the scope of the analysis to transcriptional regulation and deletion in the intron, in addition to inversion in the native genomic background. Initial analysis revealed that has a significantly lower basal expression level of transcripts in the critical reproductive stage compared to that of , suggesting that the promoter was attenuated in inducing transcription in . However, in reciprocal transgenic experiments, this promoter was able to restore partial function if coupled with the functional coding sequence, despite extensive alterations due to the self-compatible mode of reproduction in . This represents a synergistic effect of the promoter and the inversion resulting in fixation of self-compatibility, primarily enforced by disruption of . Our findings elucidate the functional and evolutionary context of the historical transition in thus contributing to the understanding of the molecular events leading to development of self-compatibility.
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http://dx.doi.org/10.3389/fpls.2020.576140DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7517786PMC
September 2020

Mechanism of self/nonself-discrimination in Brassica self-incompatibility.

Nat Commun 2020 10 1;11(1):4916. Epub 2020 Oct 1.

Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, The University of Tokyo, Tokyo, 113-8657, Japan.

Self-incompatibility (SI) is a breeding system that promotes cross-fertilization. In Brassica, pollen rejection is induced by a haplotype-specific interaction between pistil determinant SRK (S receptor kinase) and pollen determinant SP11 (S-locus Protein 11, also named SCR) from the S-locus. Although the structure of the B. rapa S-SRK ectodomain (eSRK) and S-SP11 complex has been determined, it remains unclear how SRK discriminates self- and nonself-SP11. Here, we uncover the detailed mechanism of self/nonself-discrimination in Brassica SI by determining the S-eSRK-S-SP11 crystal structure and performing molecular dynamics (MD) simulations. Comprehensive binding analysis of eSRK and SP11 structures reveals that the binding free energies are most stable for cognate eSRK-SP11 combinations. Residue-based contribution analysis suggests that the modes of eSRK-SP11 interactions differ between intra- and inter-subgroup (a group of phylogenetically neighboring haplotypes) combinations. Our data establish a model of self/nonself-discrimination in Brassica SI.
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http://dx.doi.org/10.1038/s41467-020-18698-wDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7530648PMC
October 2020

Eighteen Coral Genomes Reveal the Evolutionary Origin of Acropora Strategies to Accommodate Environmental Changes.

Mol Biol Evol 2021 01;38(1):16-30

Marine Genomics Unit, Okinawa Institute of Science and Technology Graduate University, Okinawa, Japan.

The genus Acropora comprises the most diverse and abundant scleractinian corals (Anthozoa, Cnidaria) in coral reefs, the most diverse marine ecosystems on Earth. However, the genetic basis for the success and wide distribution of Acropora are unknown. Here, we sequenced complete genomes of 15 Acropora species and 3 other acroporid taxa belonging to the genera Montipora and Astreopora to examine genomic novelties that explain their evolutionary success. We successfully obtained reasonable draft genomes of all 18 species. Molecular dating indicates that the Acropora ancestor survived warm periods without sea ice from the mid or late Cretaceous to the Early Eocene and that diversification of Acropora may have been enhanced by subsequent cooling periods. In general, the scleractinian gene repertoire is highly conserved; however, coral- or cnidarian-specific possible stress response genes are tandemly duplicated in Acropora. Enzymes that cleave dimethlysulfonioproprionate into dimethyl sulfide, which promotes cloud formation and combats greenhouse gasses, are the most duplicated genes in the Acropora ancestor. These may have been acquired by horizontal gene transfer from algal symbionts belonging to the family Symbiodiniaceae, or from coccolithophores, suggesting that although functions of this enzyme in Acropora are unclear, Acropora may have survived warmer marine environments in the past by enhancing cloud formation. In addition, possible antimicrobial peptides and symbiosis-related genes are under positive selection in Acropora, perhaps enabling adaptation to diverse environments. Our results suggest unique Acropora adaptations to ancient, warm marine environments and provide insights into its capacity to adjust to rising seawater temperatures.
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http://dx.doi.org/10.1093/molbev/msaa216DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7783167PMC
January 2021

Age-Related Differences in the Time Course of Coagulation and Fibrinolytic Parameters in Patients with Traumatic Brain Injury.

Int J Mol Sci 2020 Aug 5;21(16). Epub 2020 Aug 5.

Department of Emergency and Critical Care Medicine, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo 113-8603, Japan.

Coagulopathy and older age are common and well-recognized risk factors for poorer outcomes in traumatic brain injury (TBI) patients; however, the relationships between coagulopathy and age remain unclear. We hypothesized that coagulation/fibrinolytic abnormalities are more pronounced in older patients and may be a factor in poorer outcomes. We retrospectively evaluated severe TBI cases in which fibrinogen and D-dimer were measured on arrival and 3-6 h after injury. Propensity score-matched analyses were performed to adjust baseline characteristics between older patients (the "elderly group," aged ≥75 y) and younger patients (the "non-elderly group," aged 16-74 y). A total of 1294 cases (elderly group: 395, non-elderly group: 899) were assessed, and propensity score matching created a matched cohort of 324 pairs. Fibrinogen on admission, the degree of reduction in fibrinogen between admission and 3-6 h post-injury, and D-dimer levels between admission and 3-6 h post-injury were significantly more abnormal in the elderly group than in the non-elderly group. On multivariate logistic regression analysis, independent risk factors for poor prognosis included low fibrinogen and high D-dimer levels on admission. Posttraumatic coagulation and fibrinolytic abnormalities are more severe in older patients, and fibrinogen and D-dimer abnormalities are negative predictive factors.
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http://dx.doi.org/10.3390/ijms21165613DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7460662PMC
August 2020

Treatment for Geriatric Traumatic Brain Injury: A Nationwide Cohort Study.

J Nippon Med Sch 2020 Jun 30. Epub 2020 Jun 30.

Department of Emergency and Critical Care Medicine, Nippon Medical School.

Background: Due to aging of the Japanese population, traumatic brain injuries (TBI) in elderly individuals have increased. However, the effectiveness and prognosis of intensive treatment in geriatric TBI have not yet been determined. Thus, we analyzed the prognostic factors of intensive and aggressive treatments using nationwide data from Japan Neurotrauma Data Bank (JNTDB) projects.

Methods: We analyzed 1,879 geriatric TBI cases (≥65 years old) registered in four JNTDB projects, Project 1998 (P1998) to Project 2015 (P2015). Clinical features, aggressive treatment usage, and 6-month outcomes on the Glasgow Outcome Scale (GOS) were compared among study projects. Logistic regression was performed to clarify prognostic factors in aggressively-treated patients.

Results: The percentage of geriatric TBI cases significantly increased across time (P1998: 30.1%, Project 2004 (P2004) : 34.6%, Project 2009 (P2009) : 43.9%, P2015: 53.6%, p<0.0001). Aggressive treatment usage also significantly increased, from 67.0% in P1998 to 69.3% in P2015 (p<0.0001). Less invasive methods, such as trepanation and normothermic targeted temperature management, were more often chosen for geriatric patients. These efforts resulted in a significant decrease in the 6-month mortality rate, from 76.2% in P1998 to 63.1% in P2015 (p=0.0003), although the percentage of severely disabled patients increased, from 8.9% in P1998 to 11.1% in P2015 (p = 0.0003). Intraventricular hemorrhage was the most unfavorable prognostic factor for the 6-month outcome (OR 3.79, 95% CI 1.78-8.06, p<0.0001).

Conclusions: Less invasive treatments reduce mortality in geriatric TBI but do not improve functional outcomes. The patients' age does not seem to be the strongest prognostic factor; thus, physicians should not adhere to only age.
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http://dx.doi.org/10.1272/jnms.JNMS.2021_88-404DOI Listing
June 2020

The effects of 28-day early-life exposure to triphenyl phosphate (TPhP) on odor preference and sexual behavior in female rats.

J Appl Toxicol 2020 12 22;40(12):1614-1621. Epub 2020 Jun 22.

Laboratory of Animal Behavior and Environmental Science, Graduate School of Agriculture, Meiji University, Kawasaki, Kanagawa, Japan.

Many chemical substances are detectable in house dust, and they are consequently taken into our bodies via the mouth and nose. Triphenyl phosphate (TPhP), a flame retardant that has an estrogen-like effect in vitro, is present in house dust at high concentrations. Estrogen exposure during development has significant influences on reproductive behavior in rodents, and its effects persist until maturity. In the present study, we investigated the effect of early life exposure to TPhP on the reproductive behavior of female rats. Oral treatment with TPhP (25 or 250 mg/kg), ethinyl estradiol (EE; 15 μg/kg) as a positive control, or sesame oil as a negative control, were given to female rats (from birth to 28 days of age). The 8-week-old rats were bilaterally ovariectomized. At 12-15 weeks of age, the rats were subjected to odor preference and sexual behavior tests. In the odor preference test, the oil group showed significantly higher preference for male odor than female odor, but the low-dose TPhP treatment group lost the preference for male odor, indicating a possible outcome of early life TPhP exposure on sexual recognition. In the sexual behavior test, both the EE and TPhP treatment groups displayed significantly less proceptive behavior. These results suggest that early life exposure to TPhP disturbs the normal sexual behavior of female rats.
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http://dx.doi.org/10.1002/jat.4021DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7687172PMC
December 2020

Behavioral impairments in infant and adult mouse offspring exposed to 2,3,7,8-tetrabromodibenzofuran in utero and via lactation.

Environ Int 2020 09 16;142:105833. Epub 2020 Jun 16.

Center for Health and Environmental Risk Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba 305-8506, Japan. Electronic address:

Polybrominated dibenzo-p-dioxins and dibenzofurans (PBDD/DFs) have been unintentionally produced and emitted from the lifecycle of products containing brominated flame retardants, such as polybrominated diphenyl ether, which is suspected to cause developmental neurotoxicity (DNT). Although it is plausible that PBDD/DFs can also induce DNT, information regarding their neurotoxic potential is currently limited. Hence, in the present study, we examined the effects of in utero and lactational exposure to brominated dibenzofurans on infant and adult offspring behavior to understand the mechanism of PBDD/DFs toxicity and detect effective behavioral endpoints in DNT assessment. We analyzed the behavior of mouse offspring born to dams administered 2,3,7,8-tetrabromodibenzofuran (2,3,7,8-TeBDF; dose of 0, 9, or 45 μg/kg) or 2,3,8-tribromodibenzofuran (2,3,8-TrBDF; dose of 0, 75.6, or 378 μg/kg) on gestational day 12.5. In mouse offspring born to dams exposed to 2,3,7,8-TeBDF, the exploratory behavior in a novel environment in adulthood and ultrasonic vocalization (USV) during infancy were significantly reduced. Additionally, AhR-target genes, such as Cyp1a1, were induced in the liver of 2,3,7,8-TeBDF-exposed offspring in a dose-dependent manner. Conversely, no significant changes in the infant and adult behaviors and expression level of AhR-target genes were observed in the 2,3,8-TrBDF-exposed offspring. These results suggest that 2,3,7,8-TeBDF can induce DNT and that the analysis of exploratory behavior in a novel environment and USV may be useful endpoints to assess DNT of dioxin-related substances.
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http://dx.doi.org/10.1016/j.envint.2020.105833DOI Listing
September 2020

Characterization of self-incompatible Brassica napus lines lacking SP11 expression.

Genes Genet Syst 2020 Aug 4;95(3):111-118. Epub 2020 Jun 4.

Graduate School of Life Sciences, Tohoku University.

Recognition of self-incompatibility (SI) is regulated by the SRK and SP11 genes in Brassicaceae. Brassica rapa and B. oleracea are self-incompatible, while most cultivated species of B. napus, which arose from hybridization between B. rapa and B. oleracea, are self-compatible. Various studies of the SRK and SP11 genes in self-compatible B. napus have been reported, but details of the mechanism in different B. napus lines are not fully understood. In this study, we confirmed the S haplotypes, SI phenotypes and SP11 expression in 10 representative lines of B. napus, and identified two SI lines (N110 and N343) lacking SP11 expression. In N343 (with BnS and BnS haplotypes), we confirmed that there is a 3.6-kb insertion in the promoter region of BnSP11-1, and that BnSP11-1 and BnSP11-6 are not expressed, as reported previously (expression of BnSP11-6 is suppressed by the BnS haplotype), although this line is self-incompatible. Similarly, in N110, with two novel S haplotypes (BnS and BnS) in addition to BnS, a 4.3-kb insertion was identified in the promoter region of BnSP11-9, and expression levels of BnSP11-6, BnSP11-8 and BnSP11-9 were all suppressed (BnSP11-6 and BnSP11-8 may be suppressed by BnS and BnS, respectively), although the phenotype was self-incompatible. This observation of an SI phenotype without SP11 expression suggests the existence of unknown factor(s) that induce pollen-stigma incompatibility in B. napus.
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http://dx.doi.org/10.1266/ggs.19-00050DOI Listing
August 2020

Bioaccessibility and exposure assessment of flame retardants via dust ingestion for workers in e-waste processing workshops in northern Vietnam.

Chemosphere 2020 Jul 29;251:126632. Epub 2020 Mar 29.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, 16-2 Onogawa, Tsukuba, 305-8506, Japan.

Flame retardants (FRs) from electronic waste (e-waste) are a widespread environmental concern. In our study, in vitro physiologically based extraction tests (PBETs) for FRs were conducted in three different areas where dust remained after processing of e-waste to identify the bioaccessible FRs and quantify their bioaccessibilities of gastrointestinal tract for human as well as to assess the exposure via ingestion of workers in e-waste processing workshops. All 36 FRs were measured and detected in indoor dusts. Among the FRs, the mean concentrations of polybrominated diphenyl ethers (PBDEs) in the floor dust and settled dust were highest, 65,000 ng/g, and 31,000 ng/g, respectively. In contrast, phosphorus-containing flame retardants (PFRs) presented the highest mean concentration in the workplace dust samples, 64,000 ng/g. However, the highest bioaccessible concentrations in workplace dust, floor dust, and settled dust were observed for PFRs: 5900, 1600, and 680 ng/g, respectively. This study revealed that the higher bioaccessibility of PFRs versus other compounds was related to the negative correlation between FR concentrations and log K (hydrophobicity) values. The fact that hazard indices calculated using measured bioaccessibilities were less than 1 suggested that the non-cancer risk to human health by the FRs exposure via dust ingestion might be low.
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http://dx.doi.org/10.1016/j.chemosphere.2020.126632DOI Listing
July 2020

Estrogenic action by tris(2,6-dimethylphenyl) phosphate impairs the development of female reproductive functions.

Environ Int 2020 05 20;138:105662. Epub 2020 Mar 20.

Center for Health and Environmental Risk Research, National Institute for Environmental Studies, Japan (NIES), 16-2 Onogawa, Tsukuba 305-8506, Japan. Electronic address:

Developmental exposure to environmental chemicals with estrogen-like activity is suspected to permanently impair women's health. In this study, a mouse model was used to evaluate whether tris(2,6-dimethylphenyl) phosphate (TDMPP), a chemical with a putative estrogen-like action, impairs sexual differentiation of the brain. Either TDMPP and 17β-estradiol (E) as positive controls or sesame oil as a negative control were administered subcutaneously to dams from gestational day (GD) 14 to parturition, and to pups from postnatal day (PND) 0 to 9. Precocious puberty, irregular estrous cycles, and a lowered lordosis response were found in the TDMPP- and E-treated groups. A certain amount of TDMPP and its metabolites in the perinatal brain and the masculinization of sexual dimorphic nuclei in the hypothalamus of female mice after treatment were also detected. The experimental evidence demonstrates that TDMPP directly enters the fetal and neonatal brain, thereby inducing changes of sex-related brain structures and impairing female reproductive functions.
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http://dx.doi.org/10.1016/j.envint.2020.105662DOI Listing
May 2020

Soil and sediment contamination by unsubstituted and methylated polycyclic aromatic hydrocarbons in an informal e-waste recycling area, northern Vietnam: Occurrence, source apportionment, and risk assessment.

Sci Total Environ 2020 Mar 5;709:135852. Epub 2019 Dec 5.

Centre for Environmental Technology and Sustainable Development (CETASD), VNU University of Science, Vietnam National University, Hanoi, 334 Nguyen Trai, Hanoi, Viet Nam. Electronic address:

Improper processing activities of e-waste are potential sources of polycylic aromatic hydrocarbons (PAHs) and their derivatives, however, information about the environmental occurrence and adverse impacts of these toxic substances is still limited for informal e-waste recycling areas in Vietnam and Southeast Asia. In this study, unsubstituted and methylated PAHs were determined in surface soil and river sediment samples collected from a rural village with informal e-waste recycling activities in northern Vietnam. Total levels of PAHs and MePAHs decreased in the order: workshop soil (median 2900; range 870-42,000 ng g) > open burning soil (2400; 840-4200 ng g) > paddy field soil (1200; range 530-6700 ng g) > river sediment samples (750; 370-2500 ng g). About 60% of the soil samples examined in this study were heavily contaminated with PAHs. Fingerprint profiles of PAHs and MePAHs in the soil and sediment samples indicated that these pollutants were mainly released from pyrogenic sources rather than petrogenic sources. The emissions of PAHs and MePAHs in this area were probably attributed to uncontrolled burning of e-waste and agricultural by-products, domestic coal and biomass combustion, and traffic activities. Carcinogenicity and mutagenicity of PAHs in the e-waste workshop soils were significantly higher than those of the field soils; however, the incremental lifetime cancer risk of PAH-contaminated soils in this study ranged from 5.5 × 10 to 4.6 × 10, implying acceptable levels of human health risk. Meanwhile, concentrations of some compounds such as phenanthrene, anthracene, fluoranthene, benz[a]anthracene, and benzo[a]pyrene in several soil samples exceeded the maximum permissible concentrations, indicating the risk of ecotoxicological effects.
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http://dx.doi.org/10.1016/j.scitotenv.2019.135852DOI Listing
March 2020

Validity of using a relative potency factor approach for the risk management of dioxin-like polychlorinated naphthalenes.

Chemosphere 2020 Apr 27;244:125448. Epub 2019 Nov 27.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies, Tsukuba, 305-8506, Japan.

Here, we characterized the dioxin-like activities of 42 polychlorinated naphthalenes (PCNs) and 6 technical Halowax formulations by using the DR-CALUX (dioxin-responsive chemically activated luciferase expression) assay with rat hepatoma luciferase-expressing H4IIE cells. Of the 42 PCNs examined, 31 showed dioxin-like activities, for which the mass-based REP-EC (potency relative to that of 2,3,7,8-tetrachlorodibenzo-p-dioxin based on the 5% effective concentration determined from the dose-response curve for 2,3,7,8-TCDD) ranged from 0.00000012 to 0.0051, indicating that some of the PCNs (e.g., 1,2,3,6,7,8-HxCN and 1,2,3,4,6,7-HxCN) had dioxin-like activities that were equal to or higher than the WHO-TEFs and the mass-based REP-EC reported for dioxins such as octachlorodibenzo-p-dioxin, octachlorodibenzofuran, 3,3',4,4'-tetrachlorobiphenyl (PCB-77), 3,4,4',5-tetrachlorobiphenyl (PCB-81), and 3,3',4,4',5,5'-hexachlorobiphenyl (PCB-169). For PeCNs to OCN with high dioxin-like activities, REPs determined in previous studies were comparable to the REP values obtained in the present study. The TCDD-EQs (2,3,7,8-TCDD equivalents) obtained experimentally for the Halowax formulations decreased in the order HW1051 (37 mg/kg) > HW1014 (30 mg/kg) > HW1013 (5.6 mg/kg) > HW1099 (2.9 mg/kg) > HW1001 (0.60 mg/kg) > HW1031 (<0.10 mg/kg) and were comparable to the theoretical TCDD-EQs calculated by multiplying the concentration and REP of each PCN. In addition, the theoretical TCDD-EQs for PCNs in emission gases produced by thermal processes were below the Japanese emission standard of 0.1-10 ng WHO-toxicity equivalent (TEQ)/mN, and 3 to 4 orders of magnitude lower than the corresponding WHO-TEQ. Based on a comparison of theoretical and experimental TCDD-EQs, we found that our REP-based approach was suitable for the risk management of industrially produced and unintentionally generated dioxin-like PCNs. This approach will be particularly useful for the risk management of unintentionally generated PCNs in emission gases because the contribution of dioxin-like PCNs to the whole dioxin-like toxicity of emission gases can be elucidated.
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http://dx.doi.org/10.1016/j.chemosphere.2019.125448DOI Listing
April 2020

Genetic and tissue-specific RNA-sequencing analysis of self-compatible mutant TSC28 in Brassica rapa L. toward identification of a novel self-incompatibility factor.

Genes Genet Syst 2019 Oct 31;94(4):167-176. Epub 2019 Aug 31.

Graduate School of Life Sciences, Tohoku University.

Self-incompatibility (SI) is a sophisticated system for pollen selectivity to prevent pollination by genetically identical pollen. In Brassica, it is genetically controlled by a single, highly polymorphic S-locus, and the male and female S-determinant factors have been identified as S-locus protein 11 (SP11)/S-locus cysteine-rich protein (SCR) and S-locus receptor kinase (SRK), respectively. However, the overall molecular system and identity of factors in the downstream cascade of the SI reaction remain unclear. Previously, we identified a self-compatible B. rapa mutant line, TSC28, which has a disruption in an unidentified novel factor of the SI signaling cascade. Here, in a genetic analysis of TSC28, using an F population from a cross with the reference B. rapa SI line Chiifu-401, the causal gene was mapped to a genetic region of DNA containing markers BrSA64 and ACMP297 in B. rapa chromosome A1. By fine mapping using an F population of 1,034 plants, it was narrowed down to a genetic region between DNA markers ACMP297 and BrgMS4028, with physical length approximately 1.01 Mbp. In this genomic region, 113 genes are known to be located and, among these, we identified 55 genes that were expressed in the papilla cells. These are candidates for the gene responsible for the disruption of SI in TSC28. This list of candidate genes will contribute to the discovery of a novel downstream factor in the SP11-SRK signaling cascade in the Brassica SI system.
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http://dx.doi.org/10.1266/ggs.19-00010DOI Listing
October 2019

Time series of hexabromocyclododecane transfers from flame-retarded curtains to attached dust.

Sci Total Environ 2019 Dec 17;696:133957. Epub 2019 Aug 17.

Center for Material Cycles and Waste Management Research, National Institute for Environmental Studies (NIES), 16-2 Onogawa, Tsukuba, Ibaraki 305-8506, Japan.

While the production and new use of hexabromocyclododecane (HBCD) mostly ceased after being listed as a persistent organic pollutant under the Stockholm Convention in 2013, its emission from treated products in use to indoor environments still deserves attention. To examine the transfer of HBCD diastereomers to dust on the surface of flame-retarded curtains and to better characterize the potential of treated fabrics to be sources of HBCD in dust, we carried out a series of 196-day experiments using two types of curtains and attached dusts. Concurrently, the physicochemical properties (vapor pressure, water solubility, and octanol-water partition coefficient) of the HBCD diastereomers were measured. HBCD diastereomers migrated from curtains to dust with half-saturation times of about 20-50 days. By day 196, mean HBCD concentrations in dust had reached 13-290 μg/g, depending on the types of curtains and dusts. The composition of HBCD, dominated by γ-HBCD in the curtains, was dominated by α-HBCD in the post-experiment dusts, probably because of the higher vapor pressure of α-HBCD compared to γ-HBCD. The initial HBCD contents of the two curtains were comparable, but the concentrations and profiles of HBCD diastereomers in the post-experiment dusts differed markedly, probably because differences between the texture and/or surface finishing of the treated fabrics affected HBCD transfer to the attached dust.
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http://dx.doi.org/10.1016/j.scitotenv.2019.133957DOI Listing
December 2019

A retrospective study of the effect of fibrinogen levels during fresh frozen plasma transfusion in patients with traumatic brain injury.

Acta Neurochir (Wien) 2019 09 15;161(9):1943-1953. Epub 2019 Jul 15.

Department of Emergency and Critical Care Medicine, Nippon Medical School, 1-1-5, Sendagi, Bunkyo-ku, Tokyo, 113-8603, Japan.

Background: The association between traumatic brain injury (TBI) and coagulopathy is well established. While coagulopathy prophylaxis in TBI involves replenishing coagulation factors with fresh frozen plasma (FFP), its effectiveness is controversial. We investigated the relationship between plasma fibrinogen concentration 3 h after initiating FFP transfusion and outcomes and evaluated the correlation with D-dimer levels at admission.

Methods: We retrospectively examined data from 380 patients with severe isolated TBI with blood samples collected a maximum of 1 h following injury. Plasma fibrinogen and D-dimer concentrations were obtained at admission, and plasma fibrinogen concentration was again assessed 3-4 h following injury. The patients were divided into two groups based on whether or not they received FFP transfusion. Patients were also divided into subgroups according their fibrinogen level: ≥ 150 mg/dL (high-fibrinogen subgroup) or < 150 mg/dL (low-fibrinogen subgroup) 3 h after injury. Demographic, clinical, radiological and laboratory data were compared between these subgroups.

Results: Glasgow Outcome Scale (GOS) scores at discharge and 3 months after injury were significantly lower in the FFP transfusion group than in the FFP non-transfusion group. Among patients who received FFP, GOS scores at discharge and 3 months after injury were significantly higher in the high-fibrinogen subgroup than in the low-fibrinogen subgroup. Elevated admission D-dimer predicted subsequent fibrinogen decrease.

Conclusions: In FFP transfusion, fibrinogen level ≥ 150 mg/dL 3 h after injury was associated with better outcomes in TBI patients. Assessing the admission D-dimer and tracking the fibrinogen are crucial for optimal coagulopathy prophylaxis in TBI patients.
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http://dx.doi.org/10.1007/s00701-019-04010-3DOI Listing
September 2019