Plakevulin A induces apoptosis and suppresses IL-6-induced STAT3 activation in HL60 cells.

(+)-Plakevulin A (1), an oxylipin isolated from an Okinawan sponge Plakortis sp. inhibits enzymatic inhibition of DNA polymerases (pols) α and δ and exhibits cytotoxicity against murine leukemia (L1210) and human cervix carcinoma (KB) cell lines. However, the half-maximal inhibitory concentration (IC50) value for cytotoxicity significantly differed from those observed for the enzymatic inhibition of pols α and ß, indicating the presence of target protein(s) other than pols. This study demonstrated cytotoxicity against human promyelocytic leukemia (HL60), human cervix epithelioid carcinoma (HeLa), mouse calvaria-derived pre-osteoblast (MC3T3-E1), and human normal lung fibroblast (MRC-5) cell lines. This compound had selectivity to cancer cells over normal ones. Among these cell lines, HL60 exhibited the highest sensitivity to (+)-plakevulin A. (+)-Plakevulin A induced DNA fragmentation and caspase-3 activation in HL60 cells, indicating its role in apoptosis induction. Additionally, hydroxysteroid 17-ß dehydrogenase 4 (HSD17B4) was isolated from the HL60 lysate as one of its binding proteins through pull-down experiments using its biotinylated derivative and neutravidin-coated beads. Moreover, (+)-plakevulin A suppressed the activation of interleukin 6 (IL-6)-induced signal transducer and activator of transcription 3 (STAT3). Because the knockdown or inhibition of STAT3 induces apoptosis and HSD17B4 regulates STAT3 activation, (+)-plakevulin A may induce apoptosis in HL60 cell lines by suppressing STAT3 activation, potentially by binding to HSD17B4. The present findings provide valuable information for the mechanism of its action.

Dimethyl Sulfoxide-Free Cryopreservation of Differentiated Human Neuronal Cells.

In recent years, cells provided by cell banks and medical facilities have been used for cell therapy, regenerative therapy, and fundamental research. Cryopreservation is an effective means of maintaining stable cell quality over a long period of time. The slow freezing method is most suitable for processing many human cells isolated simultaneously from organs and tissues, but it is necessary to develop a freezing solution for this method. In this study, we report the successful development of a dimethyl sulfoxide (DMSO)-free freezing medium for differentiated neuronal cells. Neuronal differentiation results in the differentiation of undifferentiated SK-N-SH cells into neuronal cells. A basic freezing medium (BFM) was prepared using Dulbecco's modified Eagle's medium, 1 M maltose, and 1% sericin as the essential ingredients, supplemented with 5%-40% propylene glycol (PG). Each BFM supplemented with 5%-40% PG was evaluated in undifferentiated cells. After thawing, BFM supplemented with 10% and 20% PG were 83% and 88% viable, respectively. There was no significant difference between the 10% and 20% PG groups. However, a significant difference was observed when the concentration of PG in the BFM decreased by 5% (5% PG vs. 10% PG; p = 0.0026). Each DMSO-free BFM was evaluated using differentiated neuronal cells. There was no significant difference between the 10% PG BFM and stem-CB-free groups. Viability was significantly different in the 10% glycerol BFM (4.8%) and 10% PG BFM (45%) (p = 0.028). The differentiated cells with 10% PG BFM showed higher adherence to culture dishes than those with 10% glycerol BFM. These results show that BFM containing PG was effective in differentiating neuronal cells. DMSO affects the central nervous system at low concentrations. This report indicates that DMSO is unsuitable for neuronal cells with multipotent differentiation potential. Therefore, it is essential for cell banking and transplantation medicine services to select appropriate cell freezing media.

Fulminant Streptococcus suis infection detected on peripheral blood smear: A case report.

Streptococcus suis, a gram-positive coccus, is recognized as an emerging zoonotic pathogen that causes serious infections in humans, such as bacterial meningitis and sepsis, with poor outcomes. The pathogen is known to be transmitted through the consumption of raw pork or occupational exposure to pigs. A previously healthy 38-year-old woman with occupational exposure to raw pork was presented to our emergency department with a clinical diagnosis of rapidly progressive septic shock. Peripheral blood smears detected chains of cocci inside granulocytes, which led to the early recognition of gram-positive cocci in short chains before the blood culture test results. Blood cultures later tested positive for S. suis serotype 2. The patient's condition deteriorated despite aggressive resuscitative measures including antibiotics, vasopressors, multiple blood transfusions, mechanical ventilation, and renal replacement therapy. Initiation of veno-arterial extracorporeal membrane oxygenation was ineffective, and the patient died 16 h after admission. The identification of bacteria in the peripheral blood smear indicated an overwhelming infection and led to the rapid recognition of bacteremia. Our report aims to raise awareness about fatal zoonotic pathogens and to promote the unique role of peripheral blood smears that could provide preliminary diagnostic information before blood culture results.

Cryopreservation of undifferentiated and differentiated human neuronal cells.

The effective use of human-derived cells that are difficult to freeze, such as parenchymal cells and differentiated cells from stem cells, is crucial. A stable supply of damage-sensitive cells, such as differentiated neuronal cells, neurons, and glial cells can contribute considerably to cell therapy. We developed a serum-free freezing solution that is effective for the cryopreservation of differentiated neuronal cells. The quality of the differentiated and undifferentiated SK-N-SH cells was determined based on cell viability, live-cell recovery rate, and morphology of cultured cells, to assess the efficacy of the freezing solutions. The viability and recovery rate of the differentiated SK-N-SH neuronal cells were reduced by approximately 1.5-folds compared to that of the undifferentiated SK-N-SH cells. The viability and recovery rate of the differentiated SK-N-SH cells were remarkably different between the freezing solutions containing 10% DMSO and that containing 10% glycerol. Cryoprotectants such as fetal bovine serum (FBS), antifreeze proteins (sericin), and sugars (maltose), are essential for protecting against freeze damage in differentiated neuronal cells and parenchymal cells. Serum-free alternatives (sericin and maltose) could increase safety during cell transplantation and regenerative medicine. Considering these, we propose an effective freezing solution for the cryopreservation of neuronal cells.

Complete decomposition of sulfamethoxazole during an advanced oxidation process in a simple water treatment system.

A simple water treatment system consisting of a deep UV light (λ = 222 nm) source, a mesoporous TiO2/boron-doped diamond (BDD) photocatalyst, and a BDD electrode was prepared and used to decompose sulfamethoxazole (SMX) in an advanced oxidation process. The mesoporous TiO2/BDD photocatalyst used with the electrochemical treatment promoted SMX decomposition, but the mesoporous TiO2/BDD photocatalyst alone had a similar ability to decompose SMX as photolysis. Fragments produced through photocatalytic treatment were decomposed during the electrochemical treatment and fragments produced during the electrochemical treatment were decomposed during the photocatalytic treatment, so performing the electrochemical and photocatalytic treatments together effectively decomposed SMX and decrease the total organic carbon concentration to a trace.

Rod-Shaped ß-FeOOH Synthesis for Hydrogen Production under Light Irradiation.

Renewable energy is spotlighted as a resource to replace fossil fuels, and among the resources, active research on hydrogen energy is ongoing. Various methods have been developed to produce hydrogen energy using photoreduction processes. In this study, we synthesized ß-phase iron oxyhydroxide (ß-FeOOH) using a hydrothermal method with an optimal synthesis time and investigated its photofunctional properties, including hydrogen production. The obtained samples were characterized and compared with reference data. X-ray powder diffraction results corresponded to the peaks of the reference data. A rod structure was confirmed by scanning electron microscopy, and no impurities were observed. The band-gap energy of ß-FeOOH was calculated as 1.8-2.6 eV. A photoreduction process was performed based on a photo-Fenton reaction to produce hydrogen by irradiating ultraviolet (UV) on ß-FeOOH. The synthesized ß-FeOOH was subjected to UV irradiation for 24 h to produce hydrogen, and we confirmed that hydrogen was successfully produced. The properties of ß-FeOOH were evaluated after UV irradiation.

Epo-C12 inhibits peroxiredoxin 1 peroxidase activity.

Epo-C12 is a synthetic derivative of epolactaene, isolated from Penicillium sp. BM 1689-P. Epo-C12 induces apoptosis in human acute lymphoblastoid leukemia BALL-1 cells. In our previous studies, seven proteins that bind to Epo-C12 were identified by a combination of pull-down experiments using biotinylated Epo-C12 (Bio-Epo-C12) and mass spectrometry. In the present study, the effect of Epo-C12 on peroxiredoxin 1 (Prx 1), one of the proteins that binds to Epo-C12, was investigated. Epo-C12 inhibited Prx 1 peroxidase activity. However, it did not suppress its chaperone activity. Binding experiments between Bio-Epo-C12 and point-mutated Prx 1s suggest that Epo-C12 binds to Cys52 and Cys83 in Prx 1. The present study revealed that Prx 1 is one of the target proteins through which Epo-C12 exerts an apoptotic effect in BALL-1 cells.

One-Pot Synthesis of Anatase, Rutile-Decorated Hydrogen Titanate Nanorods by Yttrium Doping for Solar H2 Production.

We have prepared yttrium (Y)-doped hydrogen titanate nanorods (HTN) by a microwave-assisted hydrothermal method. Y-doped HTN showed much improved photocatalytic activities for both H2 evolution and dye decomposition. H2 production from a methanol-water solution under UV-visible light for 7 h was enhanced by a factor of 5.5 with 1 wt % Y-doping. Doping with Y3+ ions reduced the band gap of HTN by ∼0.28 eV and induced new phases of anatase and rutile. High photocatalysis by Y-doping was attributed to enhanced light absorption (smaller band gap) and effective charge separation (heterojunction). To optimize H2 production, a series of experiments examining effects of doping concentrations and non-noble surface metal (e.g., Ni, Cu, Co) loading were carefully performed. Y-doping in this work is a new and promising approach for synthesizing highly active HTN by producing the HTN/rutile/anatase heterostructure within the one-pot method.

Hydrogen Production System by Light-Induced α-FeOOH Coupled with Photoreduction.

Invited for the cover of this issue is Tetsuya Yamada, Ken-ichi Katsumata and co-workers at Tokyo Institute of Technology and Tokyo University of Science. The image depicts rust producing hydrogen and purifying the pollutants at the same time by photocatalytic reaction. Read the full text of the article at 10.1002/chem.201903642.

Synergetic effect in water treatment with mesoporous TiO2/BDD hybrid electrode.

Boron-doped diamond (BDD) electrodes have a wide potential window and can produce ozone by water electrolysis at high voltage. Though ozone has strong oxidative power (standard oxidation potential: 2.07 V vs. NHE), it cannot decompose certain types of recalcitrant organic matter completely. We developed an advanced oxidation process (AOP), in which hydroxy radicals with stronger oxidative power (standard oxidation potential: 2.85 V vs. NHE) are formed using a combination of ozone, photocatalyst, and UV. In this study, we fabricated a mesoporous TiO2/BDD hybrid electrode and examined its potential for AOPs. A synergetic effect between electrochemical water treatment and photocatalytic water treatment was observed with the hybrid electrode that did not occur with the BDD electrode.

Synthesis of a mesoporous titania thin film with a pseudo-single-crystal framework by liquid-phase epitaxial growth, and enhancement of photocatalytic activity.

A mesoporous titania thin film with a pseudo-single-crystal framework was synthesized on a lanthanum aluminate single-crystal substrate by a surfactant-assisted sol-gel method and liquid-phase epitaxial growth. The crystal lattices were well aligned within the titania framework. The highly energetic {001} facet was exposed on the top surface, which significantly enhanced the photocatalytic activity.

Cleavage of SPACA1 regulates assembly of sperm-egg membrane fusion machinery in mature spermatozoa†.

The acrosome reaction is a multi-step event essential for physiological fertilization. During the acrosome reaction, gamete fusion-related factor IZUMO1 translocates from the anterior acrosome to the equatorial segment and assembles the gamete fusion machinery. The morphological changes in the acrosome reaction process have been well studied, but little is known about the molecular mechanisms of acrosome reorganization essential for physiological gamete membrane fusion. To elucidate the molecular mechanisms of IZUMO1 translocation, the steps of the acrosome reaction during that process must be clarified. In this study, we established a method to detect the early steps of the acrosome reaction and subdivided the process into seven populations through the use of two epitope-defined antibodies, anti-IZUMO1 and anti-SPACA1, a fertilization-inhibiting antibody. We found that part of the SPACA1 C-terminus in the periacrosomal space was cleaved and had begun to disappear when the vesiculation of the anterior acrosome occurred. The IZUMO1 epitope externalized from the acrosomal lumen before acrosomal vesiculation and phosphorylation of IZUMO1 occurred during the translocation to the equatorial segment. IZUMO1 circumvented the area of the equatorial segment where the SPACA1C-terminus was still localized. We therefore propose an IZUMO1 translocation model and involvement of SPACA1.

Hydrogen Production System by Light-Induced α-FeOOH Coupled with Photoreduction.

Solar-driven catalysts on semiconductors to produce hydrogen are considered as a means to solve environmental issues. In this study, H2 production coupling with oxygen consumption by noble metal-free α-FeOOH was demonstrated even though the conduction band edge was lower than the reduction potential of H+ to H2 . For activation of α-FeOOH, an electron donor, Hg-Xe irradiation, and low pH (ca. 5) were indispensable factors. The H2 production from H2 O was confirmed by GC-MS using isotope-labeled water (D2 O) and deuterated methanol. The α-FeOOH synthesized by coprecipitation method showed 25 times more active than TiO2 . The photocatalytic activity was stable for over 400 h. Our study suggests that α-FeOOH known as rust can produce H2 by light induction.

Microwave-/UV-assisted Enhancement of the Wettability of Photoactive TiO2 Substrates Coated on an Inactive Ti/i-TiO2 Base.

Titanium dioxide (TiO2) has been proven to be an excellent system for wettability patterning purposes because of its super hydrophilic ability and its oxidative/reductive degradation of substances when exposed to UV radiation. TiO2 substrates upon which was deposited a self-assembled monolayer (SAM) of n-octadecyltrimethoxysilane (ODS) shifts the surface to become super hydrophobic, which when subjected to UV irradiation causes the ODS compound to be degraded with the substrate turning back to be super hydrophilic. Such events allow wettability patterns to be easily created. The objective of this study was to reduce the time required to construct a wettability pattern. For this purpose, highly photoactive TiO2 nanoparticles were coated onto a titanium plate whose surface had been previously oxidized at high temperatures in an electric furnace. The subsequent TiO2/Ti system was microwaved and simultaneously irradiated with ultraviolet light (UV) to further accelerate its photocatalytic activity. Using a set of photomasks and both UV and microwave irradiation, the generation of a pattern was achieved 15 times faster (2 min versus 30 min) compared to an earlier result that used only UV radiation.

Denaturation of Lysozyme with Visible-light-responsive Photocatalysts of Ground Rhodium-doped and Ground Rhodium-antimony-co-doped Strontium Titanate.

Protein denaturants play an important role in medical and biological research, and development of new denaturants is widely explored to study aging and various diseases. In this research, we treated lysozyme, a model protein, with photocatalysts of ground Rh-doped SrTiO3 (g-STO:Rh) and ground Rh-Sb-co-doped SrTiO3 (g-STO:Rh/Sb) under visible light irradiation to explore the potential of those photocatalysts as denaturants. SDS-PAGE showed that photocatalysis with g-STO:Rh induced the fragmentation of lysozyme into unidentifiable decomposition products. BCA and Bradford protein assays indicated that the peptide bonds and basic, aromatic and N-terminal amino acid residues in lysozyme were denaturated by g-STO:Rh photocatalysis. The denaturation of those amino acids, as quantified by the decreased solubility of lysozyme, was estimated to be more severe by Bradford protein assay than by BCA protein assay. Circular dichroism (CD) spectra of lysozyme revealed that the secondary structure was denatured by g-STO:Rh photocatalysis, indicating that g-STO:Rh photocatalysis is especially effective against the amino acid residues that form the secondary structure via hydrogen bonds. Furthermore, the lytic activity of lysozyme was reduced by g-STO:Rh photocatalysis, owing to denaturation of the enzyme. The visible-light-responsive photocatalyst of g-STO:Rh/Sb accelerates the oxidation reaction and has stronger oxidizing power than g-STO:Rh. Lysozyme was denatured more quickly by g-STO:Rh/Sb photocatalysis than by g-STO:Rh according to analysis by SDS-PAGE, CD spectroscopy, BCA and Bradford protein assays, and lytic activity. These results suggest that higher photocatalytic activity induces more significant denaturation of lysozyme, implying that the main factor of photocatalytic denaturation of lysozyme is oxidation. It should be noted that, as far as we know, this is the first report for denaturation of protein using visible-light-responsive photocatalyst.

Synthesis of Mesoporous TiO2/Boron-Doped Diamond Photocatalyst and Its Photocatalytic Activity under Deep UV Light (λ = 222 nm) Irradiation.

There is a need for highly efficient photocatalysts, particularly for water purification. In this study, we fabricated a mesoporous TiO2 thin film on a boron-doped diamond (BDD) layer by a surfactant-assisted sol-gel method, in which self-assembled amphiphilic surfactant micelles were used as an organic template. Scanning electron microscopy revealed uniform mesopores, approximately 20 nm in diameter, that were hexagonally packed in the TiO2 thin film. Wide-angle X-ray diffraction and Raman spectroscopy clarified that the framework crystallized in the anatase phase. Current⁻voltage (I⁻V) measurements showed rectification features at the TiO2/BDD heterojunction, confirming that a p⁻n hetero-interface formed. The as-synthesized mesoporous TiO2/BDD worked well as a photocatalyst, even with a small volume of TiO2 (15 mm × 15 mm × c.a. 1.5 µm in thickness). The use of deep UV light (λ = 222 nm) as a light source was necessary to enhance photocatalytic activity, due to photo-excitation occurring in both BDD and TiO2.

Improvement of Wettability of Photocatalytic TiO2-Coated Wafers by Microwave/UV Pre-treatment.

The wettability efficiency of TiO2-coated Ti substrate wafers was improved using a microwave/UV pre-treatment method. With the assistance of microwave heating, TiO2 substrates coating with P25 completely achieved super hydrophilic state within 5 min, which is twice as fast compared with only UV irradiation condition. Moreover, when the microwave power was increased, improvement in the wettability activity was observed. Apart from P25, coating with brookite also resulted in a good performance. The contact angle was 0° with only 10 min of irradiation.

Graphitic carbon nitride nanosheets anchored with BiOBr and carbon dots: Exceptional visible-light-driven photocatalytic performances for oxidation and reduction reactions.

The aim of this work is the fabrication of very efficient visible-light-driven photocatalysts through anchoring carbon dots and BiOBr over nanosheets of graphitic carbon nitride. Hence, a series of g-C3N4 nanosheets/Carbon dots/BiOBr (denoted as CNNS/CDs/BiOBr) nanocomposites with different amounts of BiOBr were synthesized by refluxing route. The resultant photocatalysts were characterized by XRD, EDX, SEM, TEM, HRTEM, AFM, XPS, FT-IR, UV-vis DRS, TGA, BET, and PL instruments. Among the photocatalysts, the CNNS/CDs/BiOBr (20%) nanocomposite exhibited the highest photocatalytic performance for degradations of RhB, MB, and MO under visible light, which is about 129, 29.8, and 20.5 times as superior as the CN powder, respectively. Also, photoreduction of Cr(VI) to Cr(III) over the ternary nanocomposite with 20% of BiOBr showed high photoactivity, which was 21.7-folds higher than that of the pristine CN. Reactive species trapping experiments revealed that superoxide anion radicals and hydroxyl radicals played significant role in degradation reaction of RhB. The utilized photocatalyst was recycled with negligible loss in the activity, which is important in photocatalytic processes. Finally, by studying the electrochemical behavior, the band alignments of the semiconductors were obtained and the preliminary mechanism was suggested as a direct Z-scheme system for the enhanced interfacial charge separation and transfer, which leads to the exceptional photocatalytic performance.

Stable and Highly Efficient Electrochemical Production of Formic Acid from Carbon Dioxide Using Diamond Electrodes.

High faradaic efficiencies can be achieved in the production of formic acid (HCOOH) by metal electrodes, such as Sn or Pb, in the electrochemical reduction of carbon dioxide (CO2 ). However, the stability and environmental load in using them are problematic. The electrochemical reduction of CO2 to HCOOH was investigated in a flow cell using boron-doped diamond (BDD) electrodes. BDD electrodes have superior electrochemical properties to metal electrodes, and, moreover, are highly durable. The faradaic efficiency for the production of HCOOH was as high as 94.7 %. Furthermore, the selectivity for the production of HCOOH was more than 99 %. The rate of the production was increased to 473 µmol m-2 s-1 at a current density of 15 mA cm-2 with a faradaic efficiency of 61 %. The faradaic efficiency and the production rate are almost the same as or larger than those achieved using Sn and Pb electrodes. Furthermore, the stability of the BDD electrodes was confirmed by 24 h operation.

Solution Plasma Process-Derived Defect-Induced Heterophase Anatase/Brookite TiO2 Nanocrystals for Enhanced Gaseous Photocatalytic Performance.

We report a simple room-temperature synthesis route for increasing the reactivity of a TiO2 photocatalyst using a solution plasma process (SPP). Hydrogen radicals generated from the SPP chamber interact with the TiO2 photocatalyst feedstock, transforming its crystalline phase and introducing oxygen vacancy defects. In this work, we examined a pure anatase TiO2 as a model feedstock because of its photocatalytic attributes and well-characterized properties. After the SPP treatment, the pure anatase crystalline phase was transformed to an anatase/brookite heterocrystalline phase with oxygen vacancies. Furthermore, the SPP treatment promoted the absorption of both UV and visible light by TiO2. As a result, TiO2 treated by the SPP for 3 h showed a high gaseous photocatalytic performance (91.1%) for acetaldehyde degradation to CO2 compared with the activity of untreated TiO2 (51%). The SPP-treated TiO2 was also more active than nitrogen-doped TiO2 driven by visible light (66%). The overall photocatalytic performance was related to the SPP treatment time. The SPP technique could be used to enhance the activity of readily available feedstocks with a short processing time. These results demonstrate the potential of this method for modifying narrow-band gap metal oxides, metal sulfides, and polymer composite-based catalyst materials. The modifications of these materials are not limited to photocatalysts and could be used in a wide range of energy and environment-based applications.