Advanced Materials Research Vols. 955-959

Abstract: DNA G-quadruplex (G4-DNA) has emerged as a new drug target for anti-tumor. The small compounds can induce the formation of G4-DNA and stabilize its structures, which is of potential significance for the tumor treatment. This paper focuses on our current understanding about the structure of G4-DNA, the binding mode between G4-DNA and small molecular ligands, and natural products targeting G4-DNA.

Abstract: Analyses of Rare Earth Element were made for the 486 surface samples from the western South Yellow Sea in this paper. It was found that the grain size dominates the distribution of the elements. Their contents rise with the decrease of the mean grain size. Their contents was also effected by the minerals at certain stations. The parameters of the Rare Earth Element denote the surface sediments are mostly from Yellow River in the study area.

Abstract: The corrosion behaviors of X70 pipeline steels in polluted freshwater were investigated by electrochemical measurements. Results of immersion experiments in eutrophic freshwater and pollution-free water showed that the dissolved oxygen content in the water was a key factor in determining the corrosion rate of X70 pipeline steels. Because the dissolved oxygen content in the polluted freshwater was lower than that in pollution-free freshwater, the corrosion rate of X70 pipeline steels in polluted freshwater was also lower than that in the pollution-free water. Moreover, electrochemical measurements in simulated freshwater showed that phosphoric compounds had an inhibiting influence on the corrosion of X70 pipeline steels while the nitric compounds had little this inhibiting effect.

Abstract: Adsorption-desorption characteristics of E. coli by quartz sands of five different particle size (351、319、217、71、27μm) were studied using batch equilibrium method. The results showed that quartz sands had great adsorption quantity of E. coli. The adsorption ratio could reach above 95%,when the initial microbial concentration was 10⁹ cfu/mL. With the decreased of the quartz sand particle size,the adsorption quantity increased,and adsorption reached balance faster. The Pseudo-second-order rate equation is optimal to describe adsorption kinetics of E. coli by quartz sands, and the isothermal adsorption process is suitable to describe using Henry equation. Quartz sands had small desorption ratio of E. coli,the desorption ratio increased as quartz sands particle size increased, the largest desorption ratio was only 3.6%.The desorption dynamic processes and desorption isothermal processes also can be decreased using Pseudo-second-order rate equation and Henry equation respectively. Desorption of E. coli on quartz sands existed obvious hysteresis. It indicated there existed irreversible adsorption between E. coli and quartz sands, which the E. coli adsorbed was hard to desorb. The average particle size of quartz sands have some relevance with the parameters of Henry equation and Pseudo-second-order rate equation. This shows that particle size is one of the important factors that affect the adsorption and desorption.

Abstract: Bacillus thuringiensis (BT) was the typical environmental microorganism.To explore the environmental behavior of lithium, the growth metabolism of BT under Li+ was investigated by microcalorimetry. The power-time curve showed the growth metabolic power-time curve of BT was divided into the bacterial growth phase and sporulation process. Lithium at 0.1-12mmol L-1 revealed no obvious effect to the bacterial growth phase of BT . Li+ at 0.1-4mmol L-1 stimulated the sporulation production and Li+ at 12-16mmol L-1 inhibited that respectively. While the time for initiation to produce sporulation was not influenced. However, the time for initiation to produce sporulation was earlier than the control induced by 8 mmol L-1 of Li+. The interest turning point of microcalorimetric result was confirmed by the following SEM detection. Besides the proof on environmental behavior of lithium, present results may bring related information for BT spores biological engineering transformation.

Abstract: Bosten Lake lies in semi-arid of the southern Xinjiang with hot summer, low precipitation and will be salinized and in which water plays a strategic role. The most toxicity trace metal arsenic (As) in lake sediment was taken as an object to study the environment effects when the water is increasingly salinized. Through sampling around the obviously salinity gradient area, the 191 field data were used to analyze the effect of salinity of porewater on the change of As risk to the environment. From the sample distribution between the As speciation (the As in the porewater, the exchangeable fraction and the carbonate fraction of the sedimentary As) vs. EC (salinity index), and ions concentration of Cl^-, SO₄^2-, Na⁺, Mg²⁺, K⁺ and Ca²⁺, it is inferred that the As risk is decreased when the water salinity is increasing.

Abstract: Catechol 2,3-dioxygenase (C23O), the key enzyme catalyzing the second step in the phenol degradation meta-cleavage pathway has been purified to homogeneity by one-step chromatography from bacterial strain Bacillus cereus ZL1. The culture condition was optimized according to the analysis of the biomass and C23O activity, and the separation process was monitored by SDS-PAGE method. The molecular weight of the purified C23O was 37±3KDa and the active enzyme was eluted by potassium phosphate buffer with 400 mmol NaCL using linear gradient mode on DEAE-Sepharose Fast Flow.

Abstract: Microorganisms play important biochemical and geochemical roles in the environments they inhabit. To understand structure and function of wetlands ecosystems, it is essential to identify primary drivers of microbial diversity and community structure. In this study, soil bacteria communities were profiled in Wuliangsuhai Wetland, a natural wetland located in western Inner Mongolia, China. Soils were surveyed to characterize the structure and diversity of its microbial communities using barcoded pyrosequencing based on the 16S rDNA. The most abundant bacterial groups in all four soils were the Proteobacteria, Bacteroidetes and Actinobacteria. The results of this study provide new information regarding a previously uncharacterized wetland ecosystem and show the value of highthroughput sequencing in the study of wetland ecosystems.

Abstract: The paper studies three-dimensional food-chain model with variable consumption rate in Chemostat. Assume the prey population's consumption rate of the nutrients is quadratic function, and the predator's consumption rate of the prey population is linear function. Use qualitative theory of ordinary differential equation to analyze the equilibrium solution of the model, especially the existence and stability of positive equilibrium solutions and Hopf bifurcation solutions. Finally,several numerical simulations illustrating the theoretical analysis are also given.

Abstract: SHARON-anammox process is a new energy-efficient biological denitrification process. In this paper, the basic principles of SHARON and anammox were introduced. Technical characteristics and present research status of SHARON-anammox process were analyzed, and existed questions and development trend were put forward.