Based on Response Surface Methodology, the experiments of biomass catalytic gasification designed by Design-Expert software were carried out in steam atmosphere and double-bed reactor. The response ...surface was set up with three parameters (gasification temperature, the content of K-based catalyst in gasification bed and the content of Ni-based catalyst in reforming bed) for biomass gasification performance of carbon conversion efficiency and hydrogen yield to make analysis and optimization about the reaction characteristics and gasification conditions. Results showed that gasification temperature and the content of K-based catalyst in gasification bed had significant influence on carbon conversion efficiency and hydrogen yield, whilst the content of Ni-based catalyst in reforming bed affected the gasification reactions to a large extent. Furthermore, appropriate conditions of biomass steam gasification were 800 degree C for gasification temperature, 82% for the content of K-based catalyst in gasification bed and 74% for the content of Ni-based catalyst in reforming bed by the optimization model. In these conditions, the steam gasification experiments using wheat straw showed that carbon conversion efficiency was 96.9% while hydrogen yield reached 64.5 mol/kg, which was in good agreement with the model prediction. The role of the reforming bed was also analyzed and evaluated, which provided important insight that the employment of reforming bed made carbon conversion efficiency raised by 4.8%, while hydrogen yield achieved a relative growth of 50.5%.
A rapid, convenient and accurate method using a sol–gel–alginate–carbon composite electrode (SACE) is described for the determination of β-indole acetic acid (IAA) in plant samples. The determination ...is based on an enzyme-linked competitive immunoreaction between free IAA and IAA labeled with HRP to bind on the anti-IAA IgG immobilized on the SACE surface. The response signal expressed as percentage current reduction (CR%,
y) is linearly related to the logarithm of the concentration of IAA (
x) in range of 5–500
μg
ml
−1 with a regression equation of the form
y=37.80
x−22.47 and correlation coefficient of 0.9922. The immunosensor was used to determine the IAA content in the hybrid rice grain samples taken in the growing period.
Oxidative stress and DNA damage are the most studied mechanisms by which ochratoxin A (OTA) induces its toxic effects, which include nephrotoxicity, hepatotoxicity, immunotoxicity and genotoxicity. ...Zinc, which is an essential trace element, is considered a potential antioxidant. The aim of this paper was to investigate whether zinc supplement could inhibit OTA-induced oxidative damage and DNA damage in HepG2 cells and the mechanism of inhibition. The results indicated that that exposure of OTA decreased the intracellular zinc concentration; zinc supplement significantly reduced the OTA-induced production of reactive oxygen species (ROS) and decrease in superoxide dismutase (SOD) activity but did not affect the OTA-induced decrease in the mitochondrial membrane potential (Δψm). Meanwhile, the addition of the zinc chelator N,N,N′,N′-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN) strongly aggravated the OTA-induced oxidative damage. This study also demonstrated that zinc helped to maintain the integrity of DNA through the reduction of OTA-induced DNA strand breaks, 8-hydroxy-2′-deoxyguanosine (8-OHdG) formation and DNA hypomethylation. OTA increased the mRNA expression of metallothionein1-A (MT1A), metallothionein2-A (MT2A) and Cu/Zn superoxide dismutase (SOD1). Zinc supplement further enhanced the mRNA expression of MT1A and MT2A, but it had no effect on the mRNA expression of SOD1 and catalase (CAT). Zinc was for the first time proven to reduce the cytotoxicity of OTA through inhibiting the oxidative damage and DNA damage, and regulating the expression of zinc-associated genes. Thus, the addition of zinc can potentially be used to reduce the OTA toxicity of contaminated feeds.
► OTA decreased the intracellular zinc concentration. ► OTA induced the formation of 8-OHdG in HepG2 cells. ► It was testified for the first time that OTA induced DNA hypomethylation. ► Zinc protects against the oxidative damage and DNA damage induced by OTA in vitro.
Epstein-Barr virus (EBV) infection is closely associated with nasopharyngeal carcinoma (NPC) and increases the chemotherapy resistance of tumor cells. Although the mechanism by which EBV manipulates ...ataxia telangiectasia mutation (ATM)-mediated DNA damage response in NPC has been extensively studied, the relationship between ATR (ATM and Rad-3 related) and EBV infection is largely unexplored, and also the role of ATR in chemotherapy resistance in EBV-positive NPC has not been specifically reported.
Levels of γ-H2AX, latent membrane protein 1 (LMP1), and EBV-encoded RNA in clinical NPC and nasopharyngeal inflammation (NPI) specimens were examined using immunohistochemistry and in situ hybridization. The effects of EBV infection, chemotherapy drugs cisplatin (CDDP) and 5-fluorouracil (5-FU) treatment, and ATR silencing were assessed in NPC cells in vitro using immunofluorescence, Western blot, and flow cytometry.
A notable increase of γ-H2AX expression was examined in the EBV-positive NPC clinical specimens. Additionally, we observed that the phosphorylation of ATR/checkpoint kinase 1 (CHK1) pathway protein was gradually activated along with the duration of EBV exposure in NPC cell lines, which was obviously inhibited after ATR depletion. Moreover, EBV infection promoted the resistance of NPC cells to CDDP and 5-FU, whereas the chemosensitivity of cells was significantly enhanced following ATR knockdown. Furthermore, ATR depletion caused both S-phase cell arrest and apoptosis, enhanced p53 phosphorylation, and impaired the formation of Rad51.
Our data suggest that EBV activation of ATR-mediated DNA damage response might result in chemotherapy resistance to CDDP and 5-FU in NPC. Accordingly, ATR knockdown may serve as an effective treatment strategy for chemotherapy-resistant, EBV-positive NPC.
We cloned the three androgen response elements（AREs, including AREI, AREII, and AREIII ） with a core transactivation TATA element of the prostate-specific antigen（PSA） promoter into pGL2 basic vector ...to create an artificial pGL2/AREs-TATA reporter system, which was applied to evaluating the effects of different xeno- oestrogensbisphenol A（BPA）, 4-nonylphenol（4-NP）, dichlorodiphenyl trichloroethane（DDT） or diethylstilbestrol （DES） on androgen receptor（AR） abnormal activation to regulate PSA expression and cell proliferation. In all the three AREs, AREIII-TATA displayed as a major element responsive to AR-mediated DHT stimulation of PSA promoter. Therefore, pGL2/AREIII-TATA reporter was adopted to analyze the activation capacity of AR activated by four different xeno-oestrogens. The activation of pGL2/AREIII-TATA reporter by each xeno-oestrogen was analyzed in two different cell lines, one was HEK293T（Human Embryonic Kidney 293T） cell line, and the other was AR stably expressed DU145 cell line, which was produced by infecting AR with pLenti-puro-AR into the prostate cancer DU145 cells and that were scanned with puromycin and tested by AR antibody. In both the two cell lines, BPA or DES significantly induced AR-mediated transcriptional activity of AREIII-TATA reporter, whereas DDT or 4-nonylphenol did not. Moreover, AR-mediated cell proliferation in response to each of four xeno-oestrogens was measured in MTT assays in both HEK293T cell or AR stably expressed DUI45 cell lines. BPA or DES, as an AR inducer, exhibited an enhanced effect in cell proliferation, rather than the effect of DDT or 4-NP, in both cell lines. Finally, we demonstrated that BPA or DES stimulated PSA expression and enhanced the recruitment of AR onto the PSA promoter, resulting in stronger binding to AREIII sites. Taken together, four xeno-oestrogens were identified to have different activities on AR. BPA and DES are demonstrated to be androgenic effectors in the regulation of PSA activation or cell proliferation.
A biochemical oxygen demand (BOD) sensor has been developed, which is based on an immobilized mixed culture of microorganisms combined with a dissolved oxygen (DO) optical fiber. The sensing film for ...BOD measurement consists of an organically-modified silicate (ORMOSIL) film embedded with tri(4,7-diphenyl-1,10-phenanthroline) ruthenium(II) perchlorate and three kinds of seawater microorganisms immobilized on a polyvinyl alcohol sol–gel matrix. The BOD measurements were carried out in the kinetic mode inside a light-proof cell and with constant temperature. Measurements were taken for 3
min followed by 10
min recovery time in 10
mg/L glucose/glutamate (GGA) BOD standard solution, and the range of determination was from 0.2 to 40
mg/L GGA. The effects of temperature, pH and sodium chloride concentration on the BOD sensing films were studied. BOD values estimated by this optical BOD sensing film correlate well with those determined by the conventional BOD
5 method for seawater samples.
Considering the complicated pathogenesis of Alzheimer＇s disease （AD）, multi-targets have become a focus in the discovery of drugs for treatment of this disease. In the current work, we established a ...multi-target strategy for discovering active reagents capable of suppressing both Aβ level and Tau hyperphosphorylation from natural products, and found that the ethanol extract of Thamnolia vermicularis （THA） was able to improve learning ability in APP/PSl transgenic mice by inhibiting both Aβ levels and Tau hyperphosphorylation. SH-SY5Y and CHO-APP/BACE1 cells and primary astrocytes were used in cell-based assays. APP/PSl transgenic mice B6C3-Tg（APP PSldE9） were administered THA （300 mg.kgl.d1, ig） for 100 d. After the administration was completed, the learning ability of the mice was detected using a Morris water maze （MWM） assay; immunofluorescence staining, Congo red staining and Thioflavine S staining were used to detect the senile plaques in the brains of the mice. ELISA was used to evaluate Aβ and sAPPβ contents, and Western blotting and RT-PCR were used to investigate the relevant signaling pathway regulation in response to THA treatment. In SH-SY5Y cells, THA （1, 10, 20 pg/mL） significantly stimulated PI3K/AKT/mTOR and AMPK/raptor/mTOR signalingmediated autophagy in the promotion of Aβ clearance as both a PI3K inhibitor and an AMPK indirect activator, and restrained A± production as a suppressor against PERK/elF2（x-mediated BACE1 expression. Additiojaally, THA functioned as a GSK3β inhibitor with an ICso of 1.32±0.85 pg/mL, repressing Tau hyperphosphorylation. Similar effects on Aβ accumulation and Tau hyperphosphorylation were observed in APP/PSltransgenic mice treated with THA. Furthermore, administration of THA effectively improved the learning ability of APP/PSl transgenic mice, and markedly reduced the number of senile plaques in their hippocampus and cortex. The results highlight the potential of the natural product THA for the treatment of AD.
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