Advanced Materials Research Vols. 1004-1005

Abstract: Protein is the major component of muscle tissue, in order to analyze change rule of the grass carp muscle protein during storage, the Plackett–Burman design and response surface methodology were employed to optimize its extraction conditions. The results showed that pH, SDS concentration and liquid-solid ratio were the significant factors influencing response, and the final combination of the optimized parameters was generated: pH, 8.3; liquid-solid ratio, 17:1; SDS concentration, 3.50%;beta mercaptoethanol concentration,0.3%; extraction temperature, 25 °C; extraction time, 1 h; ultrasonic time,15 min. And under these conditions, the protein extraction rate increased to 92.42%.

Abstract: The α-glucosidase gene agl from Thermus thermophilus HB8 was cloned into expression vector pBV220. The phylogenetic trees of α-glucosidases were constructed using Neighbor-Joining (NJ) and Maximum-Parsimony (MP) methods. Evolution analysis indicated the α-glucosidase from T. thermophile HB8 was distant from the other glycoside hydrolases 4 and 31 α-glucosidases. By weakening the mRNA secondary structure and replacing the rare codons for the N-terminal amino acids of the target protein, the expression level of the agl was increased 30-fold. The recombinant AGL was purified by the heat treatment, and had a molecular mass of 61 kDa. The optimal activity was at pH 7.8 and 95°C over a 10 min assay. The purified enzyme was stable over a pH range of 5.4-8.6, and had a 1-h half life at 85°C. Kinetic experiments at 90°C with p-nitrophenyl-α-D-glucoside as substrate gave a K_m, and V_max of 0.072 mM and 400 U/mg. Thus, this report provides an industrial means to produce the recombinant α-glucosidase in E. coli.

Abstract: Preparing of cool wool natural energy storage materials from wool fiber is a feasible and effective method. The structure characteristics of wool and the reason that wool has cool properties were introduced. The preparation principle, preparation methods and properties of cool wool fiber was studied. The preparation methods of cool wool mainly include scale stripping and surface coating. Scale stripping mainly consists of Chlorination, oxidation, biological enzyme treatment and plasma treatment. Surface coating mainly consists of resin finishing and ceramic finishing. Slenderizing and adding energy storage materials are also the effective methods. Wool as a new concept of natural energy storage material is recognized by people.

Abstract: Protein structure prediction is a challenging field strongly associated with protein function and evolution determination, which is crucial for biologists. Despite significant process made in recent years, protein structure prediction maintains its status as one of the prime unsolved problems in computational biology. In this study, we have developed a method for protein structure prediction based on 7-state HMM which can reduce the number of states using secondary structure information about proteins for each fold. The QPSO is an efficient optimization algorithm which is used to train profile HMM. Experiment results show that the proposed method is reasonable.

Abstract: Diabetic nephropathy (DN) is a common complication of diabetes and it is related to irreversible kidney damages and chronic renal failure. Impaired glucose tolerance (IGT) is an early stage in the development of diabetes and DN. Early detection of IGT and treatment of its associated early kidney damage can effectively prevent the development of DN. In this paper, the influence of dihydromyricetin (DHM) on lowering blood glucose concentration and reducing early kidney damage in IGT rats was studied. Animal model of IGT rats was built by two week intragastric injection of D-galactose and treated with eight weeks of intragastric injection of DHM at two dose levels. The concentrations of fasting blood glucose (FBG), two-hour postprandial blood glucose (2hBG), insulin levels, contents of microalbuminuia (mAlb) and blood urea nitrogen (BUN), and activities of lactate dehydrogenase (LDH) in kidney were analysed and compared with those in control groups. Experimental results indicated that DHM treatment can significantly lower the levels of two-hour postprandial blood glucose and insulin, decrease the content of mAlb and the activities of LDH in kidney, but does not influence the level of BUN. The study suggested that DHM can effectively improve the states of IGT rats and provide a protective effect against early kidney damage.

Abstract: Modified zein could improve functional properties of zein broadening its application. The L₉(3⁴) orthogonal experimental design was applied to optimize modification technology of zein. The results showed that the optimum parameters of zein modification were using gallic acid as modifier, ethanol 80% and modification time 2.0h. Under these conditions, the fracture elongation of modified zein was reached to 79.5%. The results showed obvious effects. The antioxidant activities of zein were determined by •OH and DPPH radicals scavenging assays. When modified zein concentration was 2.0 g/mL the scavenging capacity of DPPH and •OH reached to 34.7% and 45.2%. The antioxidant activity of zein was less than vitamin C. This study has important practical significance for deep processing of zein resources.

Abstract: Orthogonal experiment optimization of microwave-assisted extraction (MAE) conditions of total flavonoids from castor leaves with the factors of ethanol concentration, microwave power, extraction time, solid/liquid ratio on the yield of total flavonoids were studied. The results showed that optimum extracting conditions of total flavonoids from castor leaves were as follows: adding 1:50 g·mL-1 of 40% alcohol and extracting for 3 min,microwave irradiation power 464W. Microwave extraction of total flavonoids from castor leaves is fast, energy saving and high extraction rate.

Abstract: Lipid extraction process claimed about 10-20% of the total cost of microalgal fuels. Cell disruption (bead beater, a high-pressure homogenizer, ultrasoniaction, etc) followed with solvent extraction (hexane, chloroform and methyl, etc) are commonly used in lab-scale experiments. However, it is time consuming and costly to apply these methods in large-scale production. Recently, some innovative methods, such as microwave-assisted process and enzyme treatment are also found effective in lipid extraction from wet microalgae biomass. This article reviewed the current techniques commonly used in lipid extraction from wet microalgae.

Abstract: The objective of this paper was to optimize the flocculation and biomass productivity of Botryococcus braunii by using an organic carbon source glycine. The effects of culture period and glycine dose with high, medium and low levels on both solid concentration achieved and biomass productivity were conducted. It was found that extracellular polymeric substances (EPS), which promotes flocculation, was produced not only by bacterial but also by microalgae. The productivity of EPS was affected by culture period, glycine dose and mixing time. The maximum EPS of 103.3 mg/L obtained with 11 day culture period and 0.1 g/L glycine, leading to the maximum solid concentration achieved of 51 g/L, the biomass recovery rate 72%.

Abstract: Water hyacinth is an invasive weed because of its high reproductive capacity, adaptability, nutritional requirements and resistance to adverse environments. It is impossible to eradicate and difficult to control. Since water hyacinth is mainly composed of lignin, cellulose, hemicellulose and water (around 90%).This paper introduced the current researches and perspectives of the utilization of water hyacinth.