Antibacterial effects of chitosan and its water‐soluble derivatives on E. coli,plasmids DNA,and mRNA

The antibacterial activities of chitosan and its water‐soluble derivatives on E. coli were studied according to four influencing factors in vitro. The antibacterial study showed that chitosan, O‐hydroxyethyl chitosan (O‐HECS), and O‐carboxymethyl chitosan (O‐CMCS) could inhibit the growth of the microbial. To study the antibacterial mechanism, plasmid DNA pBR322 and pUC18 were selected to be the probes to find out the binding abilities of chitosans. Results showed that raw chitosan had a high binding ability with the plasmids and the influencing degrees were stable. The effects of chitosan derivatives on plasmids might be affected by space effect and static effect. With appropriate concentrations and molecular weights, the derivatives might have strong abilities to combine with DNA. The degree of influence of chitosan and its derivatives on plasmids had nothing to do with time. The experiment focusing on the relationship between chitosans and mRNA showed that O‐CMCS would hinder the synthesis of mRNA, and this may give some proof to its antibacterial mechanism. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3521–3528, 2007     

油脂化学工业中酶与微生物开发利用的新进展

评述了油脂化学工业中酶、微生物开发应用的新进展。介绍了脂肪酶的分解，脂肪酸、脂肪醇的微生物转化和利用微生物生产不饱和脂肪酸及油脂等过程。指出生物工艺学的发展前景。     

肉桂酰杯[4]芳烃的合成及清除自由基活性

杯[4]芳烃经醚化、氨解得到了含酰肼基团的中间体3,在PEG-400存在下,肉桂酰氯与3反应获得了含肉桂酰基的杯[4]芳烃衍生物4;4-经基肉桂酸与氯甲酸乙酯形成的混合酐与3反应,得到了相应的化合物5。用^1H NMR,^13C NMR及IR对4,5进行了结构表征,用MS对4进行了结构确证。DPPH·法测定4,5清除有机自由基活性的结果表明,4,5的自由基清除率约为19％,比杯[4]芳烃母体及肉桂酸都有所提高。     

(h，φ)-凸函数与(h，φ)-Lipschitz函数的一些广义微分性质

利用函数f与它的对应函数f(t)=φ(f(h~(-1)(t)))之间的关系,研究了(h,φ)-凸函数和(h,φ)- Lipschitz函数的广义方向导数,得到了R~n上连续(h,φ)-凸函效的广义方向导数的有限性、上半连续性以及估值不等式.在f是R~n上的(h,φ)-凸函数的假设下,给出了f为局部(h,φ)-Lipschitz的一个充分必要条件.并讨论了R~n上的(h,φ)-凸函数和(h,φ)-Lipschitz函数的关系,得到了(h,φ)-凸函数的广义次微分的几个基本性质.     

Synthesis and fluorescence properties of Tb（Ⅲ） complexes with pyridine-2,6-dicarboxylic acid derivatives

Two novel ligands named 4-styrylpyridine-2,6-dicarboxylic acid （4-SPDA） and 4-（4-（2-（2, 6-dicarboxypyridin-4-yl）- vinyl）styryl）pyridine-2,6-dicarboxylic acid（DSPDA） and their complexes with Tb（Ⅲ） were synthesized and characterized by infrared spectrometry, 1H nuclear magnetic resonance, elemental analysis and gas chromatograph-mass spectrometry. The ligand synthetic route was optimized. The fluorescence properties of the complex in solid state, in different kind of solvents and in solutions with different pH values were investigated in detail. The results show that the yields of DSPDA and 4-SPDA reach over 78% by Wittig-Horner reaction and other eight pyridine-2, 6-dicarboxylic acid derivatives with different substituents on pyridine ring, and their complexes with Tb（Ⅲ） are also obtained. The fluorescence intensities of the complexes with electron-donating groups are more intense than those of the complexes with electron-withdrawing groups on pyridine ring; fluorescence intensities of the complexes are the strongest in neutral solution （pH=7）, and the less the dipole moment of solvent molecule is, the stronger the fluorescence intensity is. It is found that the two ligands （4-APDA and DSPDA） are the good sensitizers for Tb（Ⅲ） ion.     

乳酸酯及其衍生物的合成研究进展

介绍了近几年来乳酸乙酯、乳酸丁酯，乳酸乙酯乙酸酯，O－酰基乳酸酯，丙酮酸乙酯，2－氯丙酸乙酯，O－对甲苯磺酰－（S）－乳酸甲（乙）酯及L（－）对甲苯磺酰乳酸乙酯的合成研究进展，提出了中国加快发展乳酸工业亟待解决的几个问题。     

环糊精及其衍生物在气相色谱手性分离中的应用

阐述了手性化合物分离的必要性，以及环糊精(CD)及其衍生物(CDs)的结构特点和作为气相色谱固定相的可能性，并简要概括CDs在气相色谱手性分离中的应用。     

丹皮酚及其席夫碱衍生物的抑菌性研究

以丹皮酚为先导,合成了丹皮酚缩1,3-丙二胺、丹皮酚缩2-羟基-1,3-丙二胺和丹皮酚缩糠胺3种丹皮酚席夫碱衍生物。琼脂扩散抑菌试验表明,丹皮酚及其衍生物对受试4种革兰氏阴性菌、阳性菌皆有明显的抑制作用。     

HEPT类HIV-1逆转录酶衍生物的CoMFA、CoMSIA及HQSAR研究

采用比较分子力场分析法（CoMFA）、比较分子相似因子分析法（CoMSIA）和分子全息定量结构关系（HQSAR）对1-[(2-羟乙氧)甲基]-6-苯硫基胸腺嘧啶(HEPT)类衍生物进行了分子活性构象选择、分子叠合、空间力场范围建立以及相应3D-QSAR模型建立。结果表明，该法所建模型对此类化合物具有良好的预测能力。CoMFA模型显示，交叉验证系数（q2）为0.565，非交互验证系数（r2）为0.892；CoMSIA模型显示，最佳q2为0.636， r2为0.953；最佳的HQSAR模型显示， q2为0.876， r2为0.929，最佳全息长度为97。根据三维等势图和HQSAR色码图设计了7个有较高活性的HEPT类化合物。     

Effects of various mixtures of ferulic acid and some of its microbial metabolic products on cucumber leaf expansion and dry matter in nutrient culture

Cucumber seedlings (Cucumis sativus cv. Early Green Cluster) ranging from 6 to 16 days of age were treated with various concentrations (0– 1 mM) of caffeic, ferulic,p-coumaric,p-hydroxybenzoic, protocatechuic, sinapic, syringic, and vanillic acids and mixtures of ferulic acid and one or two of the other phenolic acids. Seedlings were grown in full-strength Hoagland's solution which was changed every other day. Phenolic acid treatments were given with each nutrient solution change starting at day 6 or given once when seedlings were 13 or 14 days old. Leaf area, mean relative rates of leaf expansion, transpiration rates, water utilization, and the concentrations of the phenolic acids in nutrient solution were determined at one- or two-day intervals. Seedling dry weight was determined at final harvest. Seedling leaf area and dry weight were linearly related. Since leaf areas can be easily obtained without destructive sampling and leaf area expansion responds rapidly to phenolic acid treatments, it was utilized as the primary indicator of plant response. The resulting data suggested that a number of ferulic acid microbial metabolic products, as well as two other phenolic acids observed in soils (p-coumaric and syringic acid), can reduce seedling dry weight, leaf expansion, and water utilization of cucumber seedlings in a similar manner. The magnitude of impact of each of the phenolic acids, however, varied with phenolic acid and concentration. It appears that the inhibitory activity of these phenolic acids involved water relations of cucumber seedlings, since the phenolic acid treatments resulted in closure of stomata which then remained closed for several days after treatment. The data also demonstrated that the effects of mixtures of phenolic acids on cucumber seedlings may be synergistic, additive, or antagonistic. The type of response observed appeared to be related to the factor measured, the compounds in the nmixture, and the magnitued of inhibition associated with each compounds. The data also indicated that the effects of the various phenolic acids were reversible, since seedling leaf area increased rapidly once phenolic acids were removed from the root environment. Mean relative rates of leaf expansion recovered even in the presence of the various phenolic acids.Paper No. 9396 of the Journal Series of the North Carolina Agricultural Research Service. Raleigh, North Carolina. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the Agricultural Research Service and does not imply its approval to the exclusion of other products that may be suitable.