Advanced Materials Research Vols. 343-344

Abstract: Magnetic Fe₃O₄/chitosan nanoparticles were synthesized for lysozyme separation from solution. The adsorption of lysozyme was investigated on magnetic Fe₃O₄/chitosan nanoparticles at fixed pH 6.0, because the enzymatic activity of lysozyme reaches its maximum in this condition. The influence of initial lysozyme concentration, temperature and contact time on lysozyme adsorption was studied. The results of lysozyme adsorption indicated that the adsorption isotherm fitted Sips model well. The maximum adsorption capacity was 144.11mg/g at 310 K. The thermodynamic parameters, ΔG⁰, ΔH⁰ and ΔS⁰, illustrated that the adsorption of lysozyme was endothermic and spontaneous process.

Abstract: Cyanobacteria are widespread in eutrophic freshwater lakes and can produce potent toxins which pose serious risk for human and animal health, aquatic ecosystem sustainability and economic vitality. There are 9 major lakes, which eutrophication and related ecological problem had occurred in most of these lakes in Yunnan, China. In this study, water samples were collected at different sampling time from five freshwater plateau lakes, which located in the middle area of Yunnan province, to assess the cyanobacteria diversity vary with the seasons. The morphological character of cyanobacteria were observed by light microscope (LM), the genetic diversity of cyanobacteria had been demonstrated by constructed phylogenetic trees based on DNA sequence of cyanobacteria 16S-23S rRNA internal space (ITS).The results showed that a variety of cyanobacterial species were distributed in five plateau freshwater lakes. The cyanobacterial population consisted mainly of several Microcystis species as dominants in Dianchi Lake and the dominant species of cyanobacteria found in June to October of 2009 was Microcystis aeruginosa. The diversity of cyanobacteria in Caohai was higher than that of Waihai in Dianchi Lake.

Abstract: This paper deals with the surface characteristic of pyrrhotite bio-oxidized by Acidithiobacillus ferrooxidans. Large amounts of jarosite and element sulfur were determined in the bio-oxidation processe of pyrrhotite. More complicatedly, biofilm exists on the surface of pyrrhotite. This type of structured community of A. ferrooxidans was enclosed in the extracellular polymeric substances (EPS), and covered with the deposition generated in the bio-oxidation processe of pyrrhotite.

Abstract: To observe the effect of NR2B-siRNA mediated by hydroxyapatite nanoparticles (HA) on formalin-induced inflammatory pain of mice and the expression of NR2B in spinal cord. To preliminarily investigate the feasibility of HA as siRNA carrier to transfer NR2B-siRNA in vivo. The sequence-specific NR2B-siRNA of mice was designed and synthesized initially. Using HA as a siRNA carrier, green fluorescent protein(GFP)-siRNA as the control, 4 ug of NR2B-siRNA was administered into subarachnoid space of mice via conscious injection. On 7th day after intrathecal injection, formalin test was observed for 1 hour in each group, followed by dissection of lumbar segments of spinal cords immediately for use in immunohistochemical staining of NR2B. The results show that NR2B-siRNA not only significantly abolish the nociceptive response of mice in the tonic phase induced by formalin, but also decrease the amount of cells expressing NR2B protein in spinal cord, while GFP-siRNA mediated by HA don’t produce the same effects, which demonstrates that HA is capable of effectively transfering NR2B-siRNA via intrathecal injection, furthermore, HA/NR2B-siRNA complex can significantly reduce formalin-induced pain of mice, and specificly inhibit NR2B expression in spinal cord of mice.

Abstract: The extraction of pectin from pomelo peel was optimized to maximize pectin yield Y in this study. A central composite design of response surface methodology involving extracting time, extracting temperature, liquid-solid ratio and pH was used, and second-order model for Y was employed to generate the response surfaces. The optimum condition for Y was determined as follows: extracting time 1h, extracting temperature 95 °C, liquid-solid ratio 25, pH 1. Under the optimum condition, the pectin yield was 20.98%.

Abstract: Regulation of ethylene biosynthesis or action has an important effect on volatiles production in tomato (Lycopersicon esculentum) fruits. To understand the role of ethylene in the biosynthesis of fatty acid-derived aroma volatiles in tomato, we used Lichun tomato from a transgenic line with strictly suppression of ethylene biosynthesis (antisense LeACS2 tomato) and its wild type background line. This study was focused on the levels of the precursor substrates, activities and transcriptional levels of aroma volatile-related enzymes, including lipoxygenase (LOX), hydroperoxide lyase (HPL) and alcohol dehydrogenase (ADH). We also investigated the different abilities of converting the precursor substrates to aroma volatiles in ethylene suppressed transgenic and wild-type (WT) tomato fruits. Our results showed that the contents of endogenous linoleic and linolenic acid in tomato fruits were ethylene depended. Suppression of ethylene biosynthesis increased the content of endogenous linolenic acid in Lichun tomato fruit and then declined the ratio of linoleic /linolenic acid. Exogenous ethylene changed the value of linoleic acid /linolenic acid in antisense LeACS2 (ACS) tomato fruit to the similar level of WT. During the ripening of wild type Lichun tomato fruit, LOX activity was ethylene and development dependent. Suppression of ethylene biosynthesis did not inhibit the transcriptional expression of LoxC gene. And the HPL and ADH activities were partial ethylene-dependent during the ripening of wild type Lichun tomato fruit. Moreover, suppression of ethylene biosynthesis also affected the bioconversion of unsaturated-fatty acid precursors to C6 aldehydes and C6 alcohols. All these results indicated that ethylene had complicated effects on the biosynthesis of fatty acid-derived armoa volatiles by affecting the precursor’s content, enzyme activities, enzyme expression and the substrate utilization.

Abstract: To investigate the characters of Sorangium strains and the approaches for improving the production of epothilone, correlation of epothilone production and morphogenesis was studied in strains So0157-2, So0007-3 and So0003-3. On lean medium, So0157-2 could produce epothilones in a wide pH range (5.0-12.0), but formed fruiting bodies at high pH values (9.0-14.0). Formation of fruiting body did not affect the yield of epothilones in So0157-2. In So0007-3 and So0003-3, producing of epothilone was strongly coupled with the process of morphogenesis. It suggests that reduction of the association between morphogenesis and epothilone producing would prominently improve the epothilone production.

Abstract: Epothilones are a kind of poliketide macrolide with antifungal and anticancer bioactivity which are attracting more and more attention. In this paper we compared the extraction effects of epothilones with several organic solvents by comparing the recovery rates and purities. Result shows that chloroform and dichloromethane are more suitable for the extraction of epothilones than methanol which is universally used. Then we analyzed the HPLC and TLC results of the different solvents extract, and optimized the extraction method by using chloroform and ether. The final recovery rate and purity increase 114.2% and 21.53 times than methanol.

Abstract: In order to find out appropriate process for ethanol production from corn stover, wet oxidation（195°C，15 minutes）and simultaneous saccharification and fermentation (SSF) was carried out to produce ethanol. The results showed that the cellulose recovery of 92.9% and the hemicellulose recovery of 74.6% were obtained after pretreatment. 86.5% of cellulose was remained in the solid cake . After 24h hydrolysis at 50°C using cellulase（Cellubrix L）,the achieved conversion of cellulose to glucose was 64.8%. Ethanol production was evaluated from dried solid cake and the hydrolysate was employed as liquid fraction . After 142 h of SSF with substrate concentration of 8% (W/V), ethanol yield of 73.1 % of the theoretical based on glucose in the raw material was obtained by S. cerevisiae(ordinary baker’ yeast) . The corresponding ethanol concentration and volumetric productivity were 17.2g/L and 0.121g/L.h respectively. The estimated total ethanol production was 257.7 kg/ton raw material by assuming consumption of both C-6 and C-5. No obvious inhibition effect occurred during SSF. These instructions give you the basic guidelines for preparing papers for WCICA/IEEE conference proceedings.

Abstract: Soil aggregate stability as a key indicator of soil structure and erodibility to evaluate soil stability, is a product of interactions between soil environment, management practices, and land use patterns. The objective of this study was to analyze the distribution characteristics, characteristics of fractal features and stability of soil aggregates in tea plantations and eucalyptus plantations of Western Sichuan in China. The dry- and water-stable aggregate size distributions were determined by dry sieving and wet sieving methods. The results showed that soil structural properties in tea and eucalyptus plantations were similar. With increase in depth of soil layer, the aggregate stability of tea plantation soil became stronger. Comparative analysis of dry and wet sieving results showed that most of the aggregates in tea plantation soil were unstable. The soil aggregates >5mm and 0.5-0.25mm in size had higher stability, while those 2-1mm in size had lower stability. For tea plantation soil, the correlation coefficients between aggregate stability index and mean weight diameter, geometric mean diameter, fractal dimension were bigger under wet sieving than those under dry sieving. The results showed that aggregate stability index, mean weight diameter, geometric mean diameter, fractal dimension of water-stable aggregates could characterize soil aggregate stability in tea plantation ideally.