Short-term exposure to the environmentally relevant estrogenic mycotoxin zearalenone impairs reproduction in fish

Zearalenone (ZON) is one of the worldwide most common mycotoxins and exhibits estrogenic activity in the range of natural steroid estrogens such as 17β-estradiol (E2). The occurrence of ZON has been reported in drainage water, soil, wastewater effluents and rivers, but its ecotoxicological effects on fish have hardly been investigated.In this study the estrogenic potency of the ZON was compared to E2 in a recombinant yeast estrogen screen (rYES) and the effects of waterborne ZON exposure on reproduction, physiology and morphology of zebrafish (Danio rerio) were investigated in a 42-day reproduction experiment. E2 as well as ZON evoked a sigmoid concentration-response curve in the rYES with a mean EC₅₀ of 2 and 500 μg/L, respectively, resulting in an E2:ZON EC₅₀ ratio of 1:250. Exposure to ZON for 21 days reduced relative spawning frequency at 1000 and 3200 ng/L to 38.9 and 37.6%, respectively, and relative fecundity at 100, 320, 1000 and 3200 ng/L to 74.2, 41.7, 43.8 and 16.7%, respectively, in relation to the 21-day pre-exposure period. A 4.4 and 8.1 fold induction of plasma vitellogenin (VTG) was observed in male zebrafish at 1000 and 3200 ng/L ZON, respectively. Exposure to ZON did not affect fertility, hatch, embryo survival and gonad morphology of zebrafish.The results of this study demonstrate that although ZON possesses a moderate estrogenic potency in vitro, it exhibits a comparably strong effect on induction of VTG and reproduction in vivo. This indicates that ZON might contribute to the overall estrogenic activity in the environment and could therefore pose a risk for wild fish in their natural habitat.     

Adsorption of the endocrine-active compound estrone on microfiltration hollow fiber membranes

Results of studies reported here show that adsorption could result in considerable accumulation of hormones on hydrophobic hollow fiber membrane surfaces during filtration of trace-hormone-containing feed solutions with a linear adsorption isotherm applicable over the majority of the estrone concentration range examined (2.6-154 ng/L). Models based on both diffusion and surface reaction limitation were used to describe the kinetics of estrone adsorption to the membranes tested. Results indicate that the rate of adsorption of estrone to the hollow fiber membranes was limited principally by surface reaction rate rather than the rate of diffusive transport to membrane surface sites. Both adsorption and desorption kinetics were satisfactorily described by pseudo-first-order expressions. These results are of environmental significance, especially in drinking water applications, where contaminants such as natural and synthetic hormones may accumulate on the membranes and desorb during backwashing and membrane cleaning.     

Comparison of feeding corn silages from leafy or conventional corn hybrids to lactating dairy cows

Three corn hybrids (Pioneer 36F30, Mycogen TMF2450, and Mycogen TMF2404) were compared for yield and quality traits, and lactation performance and apparent digestibility by Holstein cows. The three corn silages were harvested at a target of 33 to 35% dry matter. Before harvest, six corn plants were randomly selected for plant fractionation. Grain-to-stover ratios were 0.92, 0.70, and 0.95 for the 36F30, TMF2450, and TMF2404 corn plants, respectively. Fifty-two multiparous Holstein cows were placed on a 120-d lactation trial after a 21-d covariate diet. Cows were blocked by calving date and randomly assigned within block to one of three dietary treatments, containing approximately 40% (dry matter basis) corn silage. Milk yield, milk components, and dry matter intake did not differ among dietary treatments. In vitro true and neutral detergent fiber digestibilities were numerically higher for TMF2404 than the other corn silage hybrids. Apparent total-tract crude protein and neutral detergent fiber digestibilities, as measured by acid insoluble ash, were higher for TMF2450 than the other two hybrids, but starch digestibility was not different between the corn silage dietary treatments. Although small differences in nutrient content and digestibility existed among corn silage hybrids, inclusion of these leafy hybrids in lactating cow diets at 40% of the dietary dry matter did not have a significant impact on lactation performance of dairy cattle.     

Binding of harvested bacterial exopolymers to the surface of calcite

Biologically produced exopolysaccharides (EPS) affect calcite dissolution and precipitation. In this study, natural alkaliphilic microbial isolates were collected from biofilms on historic limestone. The isolates were screened for their ability to produce significant quantities of EPS in cultures. The most productive isolates were identified by 16S rRNA sequence analysis as a close relative of Bacillus cereus. EPS with different chemical structures were harvested from the isolates. Isothermal titration calorimetry (ITC) was used to quantify the thermodynamics of binding by the harvested EPS to calcite. The binding was described by a Langmuir adsorption isotherm. Characterization of the EPS showed that binding strength to calcite depended on the chemical nature of the polymer.     

印度中央燃料研究院当前的科研项目

本文简要叙述了目前中央燃料研究院的煤炭科研项目,以及以前在煤炭科技方面所取得的成就。并就在煤炭科技的各个方面采用现代化方法和新技术的必要性进行了探讨。     

假一水氧化铝的热分析

利用TG-DTA区分了不同类型的一水氧化铝,并对生产催化剂载体用的湿法假一水氧化铝Pseudo-AlOOH(或Al_2O_3·xH_2O,1.4≤x≤2.0)进行了评价,对比x衍射分析结果,提出了判别假一水氧化铝性能的指标,为科研和生产提供了参考依据。     

Magnetic Fe(2)MO(4) (M:Fe, Mn) activated carbons: fabrication, characterization and heterogeneous Fenton oxidation of methyl orange

We present a simple and efficient method for the fabrication of magnetic Fe(2)MO(4) (M:Fe and Mn) activated carbons (Fe(2)MO(4)/AC-H, M:Fe and Mn) by impregnating the activated carbon with simultaneous magnetic precursor and carbon modifying agent followed by calcination. The obtained samples were characterized by nitrogen adsorption isotherms, X-ray diffraction (XRD), scanning electron microscopy (SEM) and vibrating sample magnetometer (VSM), and the catalytic activity in heterogeneous Fenton oxidation of methyl orange (MO) was evaluated. The resulting Fe(2)MnO(4)/AC-H showed higher catalytic activity in the methyl orange oxidation than Fe(3)O(4)/AC-H. The effect of operational parameters (pH, catalyst loading H(2)O(2) dosage and initial MO concentration) on degradation performance of the oxidation process was investigated. Stability and reusability of selected catalyst were also tested.     

The effects of acrolein on the thioredoxin system: implications for redox-sensitive signaling

The reactive aldehyde acrolein is a ubiquitous environmental pollutant and is also generated endogenously. It is a strong electrophile and reacts rapidly with nucleophiles including thiolates. This review focuses on the effects of acrolein on thioredoxin reductase (TrxR) and thioredoxin (Trx), which are major regulators of intracellular protein thiol redox balance. Acrolein causes irreversible effects on TrxR and Trx, which are consistent with the formation of covalent adducts to selenocysteine and cysteine residues that are key to their activity. TrxR and Trx are more sensitive than some other redox-sensitive proteins, and their prolonged inhibition could disrupt a number of redox-sensitive functions in cells. Among these effects are the oxidation of peroxiredoxins and the activation of apoptosis signal regulating kinase (ASK1). ASK1 promotes MAP kinase activation, and p38 activation contributes to apoptosis and a number of other acrolein-induced stress responses. Overall, the disruption of the TrxR/Trx system by acrolein could be significant early and prolonged events that affect many aspects of redox-sensitive signaling and oxidant stress.     

Quantifying in-use PM measurements for heavy duty diesel vehicles

Heavy duty emissions regulations have recently expanded from the laboratory to include in-use requirements. This paradigm shift to in-use testing has forced the development of portable emissions measurement systems (PEMS) for particulate matter (PM). These PM measurements are not trivial for laboratory work, and are even more complex for in-use testing. This study evaluates five PM PEMS in comparison to UCR's mobile reference laboratory under in-use conditions. Three on-highway, heavy-duty trucks were selected to provide PM emissions levels from 0.1 to 0.0003 g/hp-h, with varying compositions of elemental carbon (EC), organic carbon (OC), and sulfate. The on-road driving courses included segments near sea level, at elevations up to 1500 m, and coastal and desert regions. The photoacoustic measurement PEMS performed best for the non-after treatment system (ATS)-equipped engine, where the PM was mostly EC, with a linear regression slope of 0.91 and an R(2) of 0.95. The PEMS did not perform as well for the 2007 modified ATS equipped engines. The best performing PEMS showed a slope of 0.16 for the ATS-equipped engine with predominantly sulfate emissions and 0.89 for the ATS-equipped engine with predominantly OC emissions, with the next best slope at 0.45 for the predominantly OC engine.     

Comparison of fluorescence, laser-induced fluorescence, and ultraviolet absorbance detection for measuring HPLC fractionated protein/peptide mixtures

Proteomics is the study of all proteins in a biological sample. High-pressure liquid chromatography coupled online with mass spectrometry (HPLC/MS) is currently the method of choice for proteomic analysis. Proteins are extracted, separated at the protein or peptide level (after enzymatic digestion), and fractions are analyzed by HPLC/MS. Detection during off-line fractionation is generally conducted using UV-vis, which is not sensitive enough to distinguish fractions having the largest concentration of proteins/peptides and should not be combined prior to HPLC/MS. To overcome this deficiency, we utilize fluorescence or UV-laser induced fluorescence (UV-LIF) detection for measuring proteins/peptides during the off-line fractionation. Fluorescence detection allows low-abundance proteins/peptides that contain aromatic amino acids to be measured. In this study, peptide/protein samples fractionated using ion-exchange chromatography were detected using UV absorbance, fluorescence, and UV-LIF. The results indicated that fluorescence and UV-LIF were able to detect the lower abundance proteins/peptides to give a more representative chromatogram, allowing the analyst to decide which fractions should be combined prior to HPLC/tandem mass spectrometry (MS/MS) analysis.