Low molecular weight PEI-grafted carboxyl-modified soybean protein as gene carriers with reduced cytotoxicity and greatly improved transfection in vitro

SA-SP-PEI were synthesized via acylation reaction between carboxyl-modified soybean protein (SA-SP) and branched polyethylenimine (PEI) with molecular weight of 600, 1200, and 1800?Da, and designed as SA-SP-PEI600, SA-SP-PEI1200, and SA-SP-PEI1800, respectively. SA-SP-PEI could effectively condense plasmid DNA into nanoscale polyplexes and protect them from enzymatic digestion. MTT assay revealed that SA-SP-PEI exhibited reduced cytotoxicity on 293?T and SH-SY5Y cells. SA-SP-PEI1800/DNA complexes hold highest transfection efficiency on 293?T and SH-SY5Y cells with or without 10% serum, which was owing to its better serum stable and improved biocompatibility. Such polycationic soybean proteins have great potentials as gene carriers by further optimization.     

大豆油体蛋糕的制作及品质分析

目的 为比较大豆油体、单甘脂和蔗糖酯三种成分对蛋糕烘焙学特征的影响。方法 本文通过对蛋糕面胚比容、质构，蛋糕面糊比重、黏度和表面气孔特性以及理化指标检测，并对蛋糕进行感官评定进行测试。结果 结果表明，大豆油体最适添加量为4.5%。大豆油体能增加蛋糕的黏度，有助于形成稳定的乳化体系，并且大豆油体蛋糕的酸价、过氧化值和反式脂肪酸检测结果符合国家标准。结论 大豆油体和乳化剂能显著提高豆乳奶油蛋糕的比容，降低硬度，从而改善蛋糕的品质特性。     

Comparisons of β-Hairpin Propensity Among Peptides with Homochiral or Heterochiral Strands

Assemblies of racemic β-sheet-forming peptides have attracted attention for biomedical applications because racemic forms of peptides can self-associate more avidly than do single enantiomers. In 1953, Pauling and Corey proposed “rippled β-sheet” modes of H-bond-mediated interstrand assembly for alternating L- and D-peptide strands; this structural hypothesis was complementary to their proposal of “pleated β-sheet” assembly for L-peptides. Although no high-resolution structure has been reported for a rippled β-sheet, there is strong evidence for the occurrence of rippled β-sheets in some racemic peptide assemblies. Here we compare propensities of peptide diastereomers in aqueous solution to form a minimum increment of β-sheet in which two antiparallel strands associate. β-Hairpin folding is observed for homochiral peptides with aligned nonpolar side chains, but no β-hairpin population can be detected for diastereomers in which one strand contains L residues and the other contains D residues. These observations suggest that rippled β-sheet assemblies are stabilized by interactions between β-sheet layers rather than interactions within these layers.     

浅谈环保型增塑剂生产过程中污染最小化的处理措施

研究了具体的单个增塑剂生产过程中各个生产环节“三废”的产生情况，以及怎样最大限度地减少污染物生成的方法。复配型环保增塑剂是几种不同优良增塑剂的叠加，可以赋予塑料制品多方面的特性，对此类增塑剂的生产特点以及怎样控制污染物做了分析和介绍。     

Biochemical characterisation and application of lipases produced by Aspergillus sp. on solid‐state fermentation using three substrates

Lipase from Aspergillus sp. obtained by solid‐state fermentation (SSF) on wheat bran (LWB), soybean bran (LSB) and soybean bran combined with sugarcane bagasse (LSBBC) were 67.5, 58 and 57.3 U of crude lipase per gram substrate, respectively. The optimum pH of activity and stability of the LWB was between 8 and 9, and the optimum temperature of activity and stability was 50 °C and up to 60 °C, respectively. The LSB and LSBBC showed two peaks of optimum pH (4 and 6) and optimal values of temperature and stability at 50 °C. The LSB was stable in the pH range of 6–7, while LSBBC in the range of pH 4–7. All the enzymes show activities on p‐nitrophenyl esters (butyrate, laurate and palmitate). LWB stood out either on the hydrolysis of sunflower oil, presenting 66.1% of the activity over commercial lipase and on the esterification of oleic acid and ethanol, surpassing the activities of the commercial lipases studied. The thin layer chromatography showed that LWB and LSB have produced ethyl esters from corn oil, while LWB produced it from sunflower oil.     

Identification and determination of isoflavones in germinated black soybean sprouts by UHPLC−Q-TOF-MS mass spectrometry and HPLC-DAD

Ultra-performance liquid chromatography coupled with electrospray ionization tandem quadrupole time-of-flight mass spectrometry (UHPLC?Q-TOF-MS) and HPLC-DAD with an ultrasonic extraction method was developed for qualitative and quantitative compositions and contents in black soybean sprouts. Operational conditions of ultrasonic extraction were optimized by single-factor experiment. Phytochemical compositions of black soybean sprouts were identified by UHPLC?Q-TOF-MS in positive ion mode. A total of 23 compounds were tentatively characterized and identified by means of accurate mass and characteristic fragment ions. Among of them, the six isoflavones in different germinated black soybean sprouts were further quantified by HPLC-DAD. The results indicated that the calibration curves showed good linearity (r² > 0.9994). The intra-day and inter-day precision variations were less than 1.65% and 1.73%, respectively. The recoveries were in the range of 94.95–106.45%. The results indicated that the maximum amounts of isoflavones were produced on the fourth to fifth day germinated black soybean sprouts.