Ethiprole (ETH) is a phenylpyrazole insecticide that is used worldwide as an alternative to fipronil (FIP). Research on the photodegradation of ETH in aquatic environments has been limited compared with that on FIP. In this study, to clarify the photodegradation of ETH in aquatic systems, the photodegradation pathway and products were investigated using liquid chromatography and liquid chromatography-tandem mass spectrometry.
View Article and Find Full Text PDFFipronil (FIP) is a phenylpyrazole insecticide that, along with neonicotinoid insecticides, is regularly used worldwide. Photodegradation of FIP in aqueous systems is thought mainly to involve the reaction of desulfinylation to give fipronil desulfinyl (FIP-desulfinyl); however, little is known about further degradation reactions. We investigated FIP photodegradation by analyzing photodegradation products by liquid chromatography and liquid chromatography high-resolution tandem mass spectrometry using an Orbitrap instrument.
View Article and Find Full Text PDFMercury (Hg) adversely affects human and environmental health. To evaluate the mercury (Hg) speciation (methylation, demethylation, and reduction) of microorganisms in coastal seawater, we analyzed the microbial functional gene sets involved in Hg methylation (hgcA and hgcB), demethylation (merB), and reduction (merA) using a metagenomic approach in the eastern and western parts (the Kii and Bungo channels, respectively) of the Seto Inland Sea (SIS) of Japan. We determined the concentration of dissolved total mercury (dTHg) and methylated mercury (dMeHg) in seawater.
View Article and Find Full Text PDFWe report the migration of terephthalate and some low molecular weight organic compounds from poly(ethylene terephthalate) (PET) scraps in Milli-Q water and artificial seawater (ASW). The photochemical processes and the subsequent dark reactions were investigated using PET scraps obtained from postconsumer bottles of commercial non‑carbonated mineral water. Concentrations of terephthalate exponentially increased with irradiation time, reaching approximately 6-8 μmol L in ASW after 80 h irradiation.
View Article and Find Full Text PDFWe assessed the contamination, dynamics, and health risks of the pesticides cyanazine, simetryn, fenarimol, isoprothiolane, diazinon, irgarol, fenitrothion, and diuron in marine samples (seawater, sediments, plankton, fish, and other edible organisms) at various locations in the Seto Inland Sea in Japan in 2016 and 2017. Pesticide concentrations were highest at sampling sites close to the coastline, and mean concentrations in seawater were slightly higher in surface water than in bottom water. All eight pesticides were detected in plankton.
View Article and Find Full Text PDFPolycyclic aromatic hydrocarbons (PAHs) were analyzed to elucidate the distribution, ecological risk, pathways, and fluxes of these pollutants in and around the Seto Inland Sea, an industrialized coastal region of Japan. High molecular weight PAHs (5-6 rings) were primarily found in regions close to the bay estuaries, and their proportions decreased at distances further from the estuaries (offshore areas), where low molecular weight PAHs (2-4 rings) were more ubiquitous. Screening-level risk assessments revealed that the PAHs found in the sediments should have no adverse effects on benthic communities.
View Article and Find Full Text PDFThe optical properties of dissolved organic matter (DOM) from five rivers (Kokubu, Kurose, Ohta, Yamato, and Yodo) in Japan were investigated and contributions of DOM to photoformation of three reactive oxygen species (ROS) (hydroxyl radicals (OH), nitric oxide radicals (NO), and singlet oxygen (O)) were assessed. The lowest and highest mean dissolved organic carbon concentrations were for the Ohta River (0.95 (mg C) L) and Yamato River (2.
View Article and Find Full Text PDFProstaglandin E2 (PGE2), a product of the cyclooxygenase (COX) pathway, is produced by tumors and surrounding stromal cells. It stimulates tumor progression, promotes angiogenesis and suppresses the anti-tumor response. Pharmacological inhibition of PGE2 synthesis has been shown to suppress tumor initiation and growth in vivo.
View Article and Find Full Text PDFCancer immunotherapy, especially treatment with monoclonal antibodies (mAbs) that block programmed cell death-1 (PD-1)/programmed cell death-ligand 1 (PD-L1) signaling, has attracted attention as a new therapeutic option for cancer. However, only a limited number of patients have responded to this treatment approach. In this study, we searched for compounds that enhance the efficacy of anti-PD-1 mAb using mixed lymphocyte reaction (MLR), which is a mixed culture system of the two key cells (dendritic and T cells) involved in tumor immunity.
View Article and Find Full Text PDFDespite the success of immune checkpoint blockade in cancer, the number of patients that benefit from this revolutionary treatment option remains low. Therefore, efforts are being undertaken to sensitize tumors for immune checkpoint blockade, which includes combining immune checkpoint blocking agents such as anti-PD-1 antibodies with standard of care treatments. Here we report that a combination of chemotherapy (doxorubicin) and immune checkpoint blockade (anti-PD-1 antibodies) induces superior tumor control compared to chemotherapy and immune checkpoint blockade alone in the murine autochthonous polyoma middle T oncogene-driven (PyMT) mammary tumor model.
View Article and Find Full Text PDFPeroxynitrite (ONOO) is a reactive species which can degrade several classes of organic compounds via both oxidation and nitration reactions. Despite the fact that the photochemical precursors; superoxide (O·) and nitric oxide (NO·) radicals, have been measured in seawater under simulated solar radiation, there is no published report on actual measurements of photoformed peroxynitrite in seawater. Hence, this attempt was made to develop a fluorescence method by using coumarin boronic acid (CBA) as a chemical probe.
View Article and Find Full Text PDFA total of 23 road-dust and 9 house-dust samples were collected from Alexandria and Kafr El-Sheikh cities, Egypt in 2016 to investigate heavy metal (Cd, Co, Cr, Cu, Fe, Mn, Ni, Pb, and Zn) contamination, spatial distribution, sources, and health risks. The mean concentrations (mg kg) of Cd (road-dust (RD) = 0.33, house-dust (HD) = 0.
View Article and Find Full Text PDFTumor immunosuppression is a limiting factor for successful cancer therapy. The lipid sphingosine-1-phosphate (S1P), which signals through 5 distinct G protein-coupled receptors (S1PR1-5), has emerged as an important regulator of carcinogenesis. However, the utility of targeting S1P in tumors is hindered by S1P's impact on immune cell trafficking.
View Article and Find Full Text PDFHydrogen peroxide (HO) is a reactive oxygen species formed in natural water. It is reportedly toxic to aquatic organisms with a predicted no-effect concentration (PNEC) of about 380 nM. In this study, a countrywide investigation of HO concentrations in selected rivers across Japan was conducted to identify rivers that pose toxicity concerns.
View Article and Find Full Text PDFChromophoric-dissolved organic matter (CDOM) acts as the precursor to singlet oxygen (O) in natural waters, while water acts as the main scavenger. In this study, we showed that O in coastal seawater can be successfully predicted from CDOM parameters. The O steady-state concentration [O] and photoformation rate (O) varied by a factor of 6 across 13 sampling stations in the Seto Inland Sea, Japan, ranging from 1.
View Article and Find Full Text PDFThe fate of carbaryl in the Seto Inland Sea (west Japan) was predicted using a mass distribution model using carbaryl concentrations in river and sea water samples, degradation data, and published data. The predicted carbaryl concentrations in water in Kurose River and the Seto Inland Sea were 4.320 and 0.
View Article and Find Full Text PDFDiurnal changes of HO in river water during mid-summer were investigated. HO in river water increased with the increase in intensity of solar radiation in the morning, and reached a maximum at 14:00, although solar radiation reached a maximum around 12:00. In the afternoon, a gradual decrease in HO was observed, and HO reached a minimum just before sunrise.
View Article and Find Full Text PDFReactive oxygen species (ROS) including singlet oxygen (O) and hydroxylradicals (OH) photogenerated in natural waters play important roles in indirect photolysis of man-made pollutants. This study was conducted to investigate how the generation of these two ROS influences the degradation of two highly toxic insecticides (methomyl and carbaryl) in river water. To accomplish this, the reaction rate constants of O and OH with carbaryl and methomyl were determined; the degradation rate constants of the tested insecticides in ultrapure water (direct photolysis) and in river water in the presence and absence of O and OH scavengers were also measured.
View Article and Find Full Text PDFAlthough persistent organic pollutants (POPs) are currently banned or strictly controlled under the Stockholm Convention on Persistent Organic Pollutants, POPs are still distributed worldwide due to their environmental persistence, atmospheric transport, and bioaccumulation. Herein we investigated the current concentrations of POPs in the sediments from Seto Inland Sea, Japan and sought to clarify the factors currently controlling the POPs concentration of the surface sediments from Seto Inland Sea. The concentrations of hexachlorocyclohexane isomers (HCHs), dichlorodiphenyltrichloroethane and its metabolites (DDTs), and chlordane isomers (CHLs) in sediments from Seto Inland Sea were <0.
View Article and Find Full Text PDFShip fuels are highly associated with the emission of particulate matter and sulfur. Sulfur adsorbed on particulate matter in exhaust gases from fuels is generally considered to be sulfate. However, other chemical species of sulfur adsorbed on particulate matter in ship exhaust gases are not well known.
View Article and Find Full Text PDFThis study investigated spatio-temporal variations of selected pesticide residues in the Kurose River in Higashi-Hiroshima city (Hiroshima Prefecture), Japan. Water samples were collected from the river at seven sites every month for 1 year (March 2016 to February 2017). Pesticide residues were extracted from the samples by a solid phase extraction using Sep Pack C cartridges.
View Article and Find Full Text PDFA non-enzymatic fluorescence method for the determination of hydrogen peroxide (HO) was investigated. This method is based on the hydroxylation reaction of terephthalate (TP) by hydroxyl radical formed from reaction between HO and Fe(II), resulting in the formation of a strongly fluorescent 2-hydroxyterephthalate (HTP). Under optimized conditions, a 3 nM detection limit and 1.
View Article and Find Full Text PDFThis study was designed to investigate selected road-dust associated heavy metals, their relations with natural and anthropogenic sources, and potential human and environmental health risks. For this purpose, 42 and 36 road-dusts samples were collected from Jalalabad and Kabul cities (Afghanistan), respectively. The following elements were found in descending concentrations: Mn, Zn, Pb, Ni, Cu, Cr, Co, and Cd in Jalalabad; and Mn, Zn, Ni, Cu, Cr, Pb, Co, and Cd in Kabul.
View Article and Find Full Text PDFA mass distribution model was used to predict the fate of Diuron, Irgarol 1051 and Fenitrothion in Seto Inland Sea which is located in western Japan. This was done by using concentration, degradation, and literature data. Diuron and Irgarol 1051 in Seto Inland Sea are mainly derived from antifouling paints used for ships and boats.
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