Search

To investigate the effects of genotype and growing environment on avenanthramides and antioxidant activity of oats, the total phenolic content (TPC), avenanthramide compositions, and antioxidant activity were determined for whole oat from 39 cultivars grown in four locations in northwestern China (Inner Mongolia, Qinghai, Shanxi and Gansu). The results demonstrated that environment (E), genotype (G) and the interaction of these factors (E × G) significantly affected TPC, concentration of avenanthramide 2c (2c, ranged from 6.24 to 136.20 mg kg −1 ), avenanthramide 2p (2p, 6.07–112.25 mg kg −1 ), avenanthramide 2f (2f, 7.26–222.77 mg kg −1 ) and antioxidant activity of oats. The effect of E was considerably greater than that of G or E × G. Based on G plus G × E interaction biplots (GGE biplots) analysis, the four locations in northwestern China can be divided into either two or three regions. Qinghai was determined to be distinct from the other locations. Cultivar Bayou 9 and oats grown in Gansu exhibited the highest TPCs, concentrations of 2c, 2p, 2f and antioxidant activity. The results suggest that oats containing more avenanthramides and exhibiting high levels of antioxidant activity could be obtained by selecting an appropriate genotype and growth location. [ABSTRACT FROM AUTHOR]

Ricin is a potent ribotoxin that is considered a bioterror threat due to its ease of isolation and possibility of aerosolization. In yeast, mutation of arginine residues away from the active site results in a ricin toxin A chain (RTA) variant that is unable to bind the ribosome and exhibits reduced cytotoxicity. The goal of the present work was to determine if these residues contribute to ribosome binding and cytotoxicity of RTA in mammalian cells. The RTA mutant R193A/R235A did not interact with mammalian ribosomes, while a G212E variant with a point mutation near its active site bound ribosomes similarly to wild-type (WT) RTA. R193A/R235A retained full catalytic activity on naked RNA but had reduced activity on mammalian ribosomes. To determine the effect of this mutant in intact cells, pre R193A/R235A containing a signal sequence directing it to the endoplasmic reticulum and mature R193A/R235A that directly targeted cytosolic ribosomes were each expressed. Depurination and protein synthesis inhibition were reduced by both pre- and mature R193A/R235A relative to WT. Protein synthesis inhibition was reduced to a greater extent by R193A/R235A than by G212E. Pre R193A/R235A caused a greater reduction in caspase activation and loss of mitochondrial membrane potential than G212E relative to WT RTA. These findings indicate that an RTA variant with reduced ribosome binding is less toxic than a variant with less catalytic activity but normal ribosome binding activity. The toxin-ribosome interaction represents a novel target for the development of therapeutics to prevent or treat ricin intoxication. [ABSTRACT FROM AUTHOR]

The public's stated value and heterogeneous preferences are crucial for formulating policies and financing approaches to promote the control of agricultural non-point-source pollution (ANSP). This study aims to investigate urban residents' willingness to pay (WTP) for ANSP control and analyse the source of preference heterogeneity using a choice experiment method. Survey data were obtained from face-to-face interviews with 595 respondents in south Shaanxi Province, China. We found that respondents' average WTP for the attributes of ANSP control schemes were 2.34 yuan ($0.36) and 5.42 yuan ($0.83) per year per household for a 1% reduction in fertiliser and pesticide use, respectively. We also found significant impacts of WTP from individuals' socio-economic characteristics (i.e., gender, age, education, and income) and cognitive factors (i.e., policy understanding, and government trust). Thus, to improve the efficiency and universality of ANSP control policy, the public's willingness and preference heterogeneity should be thoroughly taken into policy formulation. [Display omitted] • Most urban residents are willing to pay a certain fee for ANSP control. • Public's marginal willingness to pay for the reduction of fertiliser and pesticide 2.34 yuan ($0.36) and 5.42 yuan ($0.83) per year per household for a 1% reduction in fertiliser and pesticide use, respectively. • Reference heterogeneity of urban residents' WTP exists and comes from individuals' socio-economic characteristics and cognitive factors. • When collecting ecological compensation funds from the public, policymakers should fully consider these heterogeneous preferences to formulate adaptive policy and management approaches. [ABSTRACT FROM AUTHOR]

Abstract: Objective. : The aim of study was to investigate the proliferative effects of stromal cell-derived factor-1α (SDF-1α) on endometrial carcinomas cell lines with different estrogen receptors (ER) and PTEN protein profiles. Methods. : MTT assays was used to detect the proliferation of HEC-1A and Ishikawa cells, and Western blotted analysis was used to detect activation of Akt and ERK1/2 in both cell lines after exposure to various concentrations of SDF-1α, MAPK-specific inhibitor PD98059 or PI3K-specific inhibitor LY294002. Results. : Low concentrations of SDF-1α (≤50 ng/ml) significantly promoted proliferation of Ishikawa cells but not of HEC-1A, while high concentrations of SDF-1α (>50 ng/ml) induced proliferation in both cell lines. ERK1/2 was significantly activated for more than 2 h by SDF-1α at 20 ng/ml in HEC-1A cells, but not in Ishikawa cells. In contrast, Akt was significantly activated for over 2 h in Ishikawa cells but remained unchanged in HEC-1A cells. High concentrations of SDF-1α activated Akt and ERK1/2 pathways in both cell lines in a dose-dependent manner, which was primarily inhibited by LY294002 for pAkt and by PD98059 for pERK 1/2. Conclusions. : SDF-1α could stimulate the cell proliferation of endometrial carcinoma with different expression status of ER and PTEN in vitro, likely through the activation of both Akt and ERK1/2 signaling pathways. [Copyright &y& Elsevier]

Ricin is one of the most toxic substances known and a type B biothreat agent. Shiga toxins (Stxs) produced by E. coli (STEC) and Shigella dysenteriae are foodborne pathogens. There is no effective therapy against ricin or STEC and there is an urgent need for inhibitors. Ricin toxin A subunit (RTA) and A1 subunit of Stx2a (Stx2A1) bind to the C-terminal domain (CTD) of the ribosomal P-stalk proteins to depurinate the sarcin/ricin loop. Modulation of toxin-ribosome interactions has not been explored as a strategy for inhibition. Therefore, development of assays that detect inhibitors targeting toxin-ribosome interactions remains a critical need. Here we describe a fluorescence anisotropy (FA)-based competitive binding assay using a BODIPY-TMR labeled 11-mer peptide (P11) derived from the P-stalk CTD to measure the binding affinity of peptides ranging from 3 to 11 amino acids for the P-stalk pocket of RTA and Stx2A1. Comparison of the affinity with the surface plasmon resonance (SPR) assay indicated that although the rank order was the same by both methods, the FA assay could differentiate better between peptides that show nonspecific interactions by SPR. The FA assay detects only interactions that compete with the labeled P11 and can validate inhibitor specificity and mechanism of action. [Display omitted] • There is no effective therapy against ricin or Shiga toxin producing E. coli and there is an urgent need for inhibitors. • A fluorescence anisotropy assay was developed for peptides that inhibit ribosome binding of ricin and Shiga toxin 2. • The FA assay can differentiate between peptides that show nonspecific interactions by the surface plasmon resonance assay. • The FA assay can validate the specificity of inhibitors that bind at the P-stalk pocket of ricin and Shiga toxin 2. [ABSTRACT FROM AUTHOR]

The extreme potency of the plant toxin, ricin, is due to its enzymatic subunit, RTA, which inactivates mammalian ribosomes with near-perfect efficiency. Here we characterized, at the functional and structural levels, seven alpaca single-domain antibodies (V H Hs) previously reported to recognize epitopes in proximity to RTA's active site. Three of the V H Hs, V2A11, V8E6, and V2G10, were potent inhibitors of RTA in vitro and protected Vero cells from ricin when expressed as intracellular antibodies ("intrabodies"). Crystal structure analysis revealed that the complementarity-determining region 3 (CDR3) elements of V2A11 and V8E6 penetrate RTA's active site and interact with key catalytic residues. V2G10, by contrast, sits atop the enzymatic pocket and occludes substrate accessibility. The other four V H Hs also penetrated/occluded RTA's active site, but lacked sufficient binding affinities to outcompete RTA-ribosome interactions. Intracellular delivery of high-affinity, single-domain antibodies may offer a new avenue in the development of countermeasures against ricin toxin.toxin, antibody, structure, intracellular Image 1 • Ricin's catalytic subunit (RTA) inactivates ribosome with high efficiency. • Alpaca single-domain antibodies (VHH) that target RTA's active site identified. • Intracellular expression (intrabody) of VHHs neutralizes ricin toxin. • Seven crystal structures of VHH-RTA complexes reported. • Results pave the way for novel antitoxin therapies. [ABSTRACT FROM AUTHOR]

Abstract: Objective: The human papillomavirus (HPV) oncoprotein, E6, activates telomerase reverse transcriptase (TERT) expression and causes cellular immortalization. It remains unclear whether E6 affects TERT transcription by altering DNA methylation profiles. In this study, we explored the methylation status of the TERT promoter in cervical cancer cell lines and its variations after E6 was silenced by RNAi. Methods: Three kinds of cervical cell lines (HPV16 positive: CaSki and SiHa; HPV18 positive: HeLa), were taken to analyze the methylation status of the TERT promoter by methylation-specific polymerase chain reaction (MSP) and bisulfite sequencing (BS). Stealth RNAi was transiently transfected to these cell lines to silence the expression of HPV16/18 E6, and the subsequent changes of TERT mRNA levels and TERT promoter DNA methylation were examined. Results: Hypomethylation of the DNA around the TERT transcription start site (−156 to +162bp) was functionally related to its transcription. After transfection with Stealth RNAi, the levels of HPV16/18 E6 and TERT mRNA were greatly decreased. The methylated CpG around the transcription start sites in CaSki and SiHa cells were statistically increased (respectively P =0.016, P =0.000). However, there was no significant difference in HeLa cells (P =0.128). Conclusion: Hypomethylated CpG around the transcription start site enables the expression of TERT in cervical cancer cells. Our results show for the first time that HPV16 E6 can promote TERT transcription through demethylating the DNA sequence around the TERT transcription start site in cervical squamous cancer cells. [Copyright &y& Elsevier]