Advanced Materials Research Vols. 1073-1076

Abstract: In recent years, the mechanized soil compaction is becoming increasingly prominent problem with the rapid increase of agricultural mechanization level. The paper expounded that soil compaction influenced on soil environment including bulk density, hardness, porosity of soil, which resulted in soil structural characteristics change and soil quality degradation, it went against crops production. The improvement measures were proposed including agronomic measures, field craft measures, tractors driving and walking device technological improvement measures and loose soil measures for soil compaction.

Abstract: Dichlorvos is an environmental hormone insecticide, and several studies have demonstrated its toxic effects on C. elegans. However, little is known about its effect on the population growth rate of nematode cohort. After exposing worms to dichlorvos (1, 10 and 50 μmol/L) for 4h, a life table experiment was conducted by a hanging-drop method with a semi-fluid culture medium. Results showed that the survival rate and fecundity of worms decreased significantly, and concentration-dependent inhibitions were also observed in net reproductive rate, total fertility rate, average lifespan and population growth rate, so these parameters were approved to be sensitive to dichlorvos, and could be used as monitors of dichlorvos pollutant. The life table experiment measured several life-cyle traits simultaneously, and integrated them into population growth rate, which reflects a population’s response to a specific pollutant. The experimental results proved that life table experiment was important for assessment of pollutants.

Abstract: Carotenoids demonstrated multiple antioxidant activities, including the ability to scavenge single oxygen and reactive oxygen radicals. Superoxide anion/radials, produced by exogenous chemical or physical stimuli and endogenous metabolic processes, can be another source of harmful reactive oxygen species (ROS) in vivo. The main components of carotenoids, lycopene, from Blakeslea trispora were separated by HPLC. In the current study, we reported the direct scavenging of superoxide anion by the carotenoids from Blakeslea trispora evaluated by electron paramagnetic resonance (EPR) spectroscopy, employing the spin-trap DMPO.

Abstract: The Zijinshan bioheapleaching plant started operating at the end of 2005. During four years of leaching operation, concern about migration of acidophiles from the heap into the nearby Ting river has arisen. A total of 44 soil samples, 49 water samples and 15 air samples were collected surround the heap at different spatial scales, and the quantitative distribution of acidophile around Zijinshan bioheap was studied. Chemical characteristics of the samples such as pH, copper content and iron content were analyzed. Real-time PCR assay was used to qualify acidophiles, included genus Acidithiobacillus, Leptospirillum, Ferroplasma and Sulfobacillus in all samples. The results showed that the four acidophiles displayed different biogeographic patterns. Geographic distance did not have a biogeographical effect on the experimental spatial scale for the genus Acidithiobacillus, Leptospirillum and Sulfobacillus. However, the geographic distance was a significant factor for genus Ferroplasma. The water soluble copper and iron concentrations of soil samples had crucial relevance for the existence of acidophiles. No significant variation was found among all the water samples regarding the concentation of acidophiles. The concentration of copper in the river met China National water quality II standard. These results indicated that: a) the dispersal of acidophiles from the heap may not be significant b) the adverse impact from the heap on the local environmental may not be significant.

Abstract: In this paper, the effect of nitric oxide (NO) on the secondary metabolites of Taxus chinensis var. mairei under elevated UV-B radiation was studied. The 5-year-old seedlings were used as test materials. The sodium nitroprusside (SNP) was as the NO donor and Carboxy-PTIO potassium salt (cPTIO) as the NO scavenger. The results showed that the SNP, UV, UV-B+SNP treatments significantly increased the contents of photosynthetic pigments (p<0.05). The contents of chlorophyll a, chlorophyll b, carotenoid and total chlorophyll exhibited CK < cPTIO < UV-B+cPTIO < UV-B < SNP < UV-B+SNP. SNP, cPTIO, UV-B, UV-B+SNP and UV-B+cPTIO significantly increased the concentrations of flavonoids, condensed tannins, total phenolics and taxol (p<0.05). Spraying SNP and cPTIO had significant effect on the taxol concentration (p<0.05). The concentrations of flavonoids, condensed tannins, total phenolics and taxol reached the maximum under the UV-B+cPTIO treatment. Spraying different concentrations of SNP or cPTIO might affect the NO content in plants, and then impact on the secondary metabolism, which mechanism needs further investigation.

Abstract: The photosynthetic pigments of Sagittaria sagittifolia, including total chlorophyll content, chlorophyll a content, chlorophyll b content and carotenoid content, were investigated after 0, 7, 14 and 21 d exposure to 3 mg L^-1 P. After 7 d P-exposure, total chlorophyll content, chlorophyll a content and chlorophyll b content increased significantly compared with the control, and then decreased with time extended. Carotenoid content increased significantly after 14 d P-exposure compared with the control, and then decreased slightly after 21 d P-exposure.

Abstract: In this study, a novel microwave-assisted extraction (MAE) method has been developed for the extraction and determination of the major biologically active compounds, crocin and its seven trans-cis analogues in a traditional Chinese medicine (TCM), gardenia fruits (Gardenia jasminoides Ellis) with analysis by reversed phase HPLC. Sudan I [1-phenylazo-2-naphthol] was selected as the internal standard. The results of quantitative determination of seven crocin analogues in six commercial gardenia fruits samples show that MAE–HPLC is a simple, rapid, low cost and reliable method for the determination of biologically active compounds, crocin analogues in TCM, and also a potential and powerful tool for quality assessment of gardenia fruits (Gardenia jasminoides Ellis).

Abstract: In the present study, the SDA (specific denitrification activity) and SMA (specific methanogenic activity) in Start up of mixotrophic anammox reactor was optimized by applying the response surface method (RSM). The purpose of this work was to find the optimal combination of C/N ratio, influent ammonium (NH₄⁺-N) and volatile suspended solid (VSS) with respect to minmum the SDA and SMA. Based on the RSM results, the quadratic model developed for the responses indicated that optimal conditions were C/N ratio of 0.5, influent NH₄⁺-N content of 200mg L^-1, and VSS content of 59.31g L^-1. Under this conditions, the SDA and SMA were minimize and found to be 0.05 mmol N₂ (g VSS d)^-1, 0.017 mmol N₂ (g VSS d)^-1, respectively

Abstract: A nanoSiO2/polyacrylamide (PAM) organic–inorganic nanocomposite system was prepared using acrylamide as the monomer, nanoSiO2 as the modifier, and ammonium persulfate as the initiator. The system was then used to investigate the impact of various factors, including amount of modifier and concentration of monomer, thereby determining the conditions for optimal reaction. Infrared spectroscopy was then used for structural characterization. Measurements using the viscosity method indicated that the viscosity average molecular weight of the product exceeded 1 million. Electron microscopy images showed that a good organic coating layer formed on the surface of the microspheres.

Abstract: A hoagland solution hydroponic experiment was carried out to study the short-duration (8 d) accumulation ability of uranium by Eichhornia crassipes and Pistia stratiotes under different uranium concentration. Effects on antioxidant enzymes (SOD, CAT, POD) activity, malondialdehyde (MDA) and free proline content of E. crassipes and P. stratiotes under uranium stress were discussed. The results show the activity of antioxidant enzymes is increased under 0.1~1 mg·L^-1 uranium stress, MDA content is at lower level indicated that antioxidant enzymes play an important role in alleviating lipid peroxidation induced by uranium stress. Under 5mg·L^-1 uranium stress, the antioxidant enzymes activity of E. crassipes is at higher level and MDA content is lower,nevertheless, the P. stratiotes is just the opposite, indicating that E. crassipes tolerated higher concentrations than P. stratiotes. The activity of antioxidant enzymes is inhibited under higher concentration (20 mg·L^-1 and 50 mg·L^-1) uranium stress. As an important osmoregulation material, free proline content of both plants is more than the contrast.