LPS1, Encoding Iron-Sulfur Subunit SDH2-1 of Succinate Dehydrogenase,Affects Leaf Senescence and Grain Yield in Rice

The iron-sulfur subunit (SDH2) of succinate dehydrogenase plays a key role in electron transport in plant mitochondria. However, it is yet unknown whether SDH2 genes are involved in leaf senescence and yield formation. In this study, we isolated a late premature senescence mutant, lps1, in rice (Oryza sativa). The mutant leaves exhibited brown spots at late tillering stage and wilted at the late grain-filling stage and mature stage. In its premature senescence leaves, photosynthetic pigment contents and net photosynthetic rate were reduced; chloroplasts and mitochondria were degraded. Meanwhile, lps1 displayed small panicles, low seed-setting rate and dramatically reduced grain yield. Gene cloning and complementation analysis suggested that the causal gene for the mutant phenotype was OsSDH2-1 (LOC_Os08g02640), in which single nucleotide mutation resulted in an amino acid substitution in the encoded protein. OsSDH2-1 gene was expressed in all organs tested, with higher expression in leaves, root tips, ovary and anthers. OsSDH2-1 protein was targeted to mitochondria. Furthermore, reactive oxygen species (ROS), mainly H₂O₂, was excessively accumulated in leaves and young panicles of lps1, which could cause premature leaf senescence and affect panicle development and pollen function. Taken together, OsSDH2-1 plays a crucial role in leaf senescence and yield formation in rice.     

PBS降解性能与环境影响评价的研究

从聚丁二酸丁二醇酯(PBS)的合成原料、低聚物及降解产物等方面探讨了PBS在生物降解过程中对种子发芽、植物的生长和环境理化性状的影响,旨在评价PBS在生物降解过程中对环境的影响。结果表明,当丁二酸浓度高于500 mg/L时,抑制种子的生长;PBS低聚物降解初期的产物,抑制植物幼苗的生长;在40 d的降解过程中,PBS显示了一定的降解性,并为能在陕西当地土壤中筛选、培养出降解PBS的微生物提供了依据。     

壬基酚聚氧乙烯醚琥珀酸酯合成条件的研究

在原有合成壬基酚聚氧乙烯醚琥珀酸酯方法的基础上,讨论了催化剂种类、原料配比及其他反应条件对反应的影响,确定了壬基酚聚氧乙烯醚琥珀酸酯的最佳合成条件:催化剂为自制催化剂,原料摩尔比1.00:1.04,反应温度(94±2)℃,真空度15.5 kPa,反应时间3 h。     

Dielectric spectroscopy of poly(butylene succinate) films

Dielectric properties of poly(butylene succinate) crystallized under different conditions have been reported in the temperature range of 163-383 K and in the frequency range of 0.01-10⁵ Hz. Both the dipolar α and β processes have been identified at low temperatures: the α process is associated with the amorphous fraction while the β with the relaxations in both the amorphous and crystalline fractions. The space charge effect dominates the high temperature dielectric spectra. These spectra have been analyzed in the light of an equivalent circuit model. The Maxwell-Wagner-Sillars polarization, electrode polarization and free charge motion are well resolved. At 383 K, near the melting temperature (387 K), massive melting and subsequent recrystallization have been observed. The peculiar evolution of the spectra is also analyzed using the same equivalent circuit model. The relationship between the fitting parameters and the evolved microstructures is discussed.     

高相对分子质量可生物降解聚丁二酸丁二醇酯的合成

以丁二酸和丁二醇为原料,采用溶液与熔融结合法合成了高相对分子质量可生物降解的聚丁二酸丁二醇酯(PBS)。考察了8种单催化剂和7种双催化剂对合成PBS反应的催化性能,采用傅里叶变换红外光谱和核磁共振方法对PBS的结构进行了表征,采用凝胶渗透色谱、热重分析和万能实验机测定了PBS的相对分子质量及其分布、热稳定性和力学性能。实验结果表明,采用单催化剂时,PBS相对分子质量的大小顺序为:SnCl2>Ti(OBu)4>Ti(iOPr)4>Sn(Oct)2>Zn(OAc)2>MgHPO4>732型酸性阳离子交换树脂>P-TS(P-TS为对甲苯磺酸);采用双催化剂时PBS的相对分子质量大于采用单催化剂时的PBS;SnCl2/P-TS双催化剂对合成PBS反应的催化性能最好,PBS的数均相对分子质量达8.95×104,相对分子质量分布为1.77,断裂伸长率达391%。     

Lewis酸性离子液体催化合成丁二酸二异丙酯

采用两步法制备了9种不同的Lewis酸性离子液体,采用¹H NMR、FT-IR对离子液体的结构进行了表征,并系统地考察了其对丁二酸和异丙醇酯化反应的催化性能。结果表明,离子液体随着卤化物用量增加表现出更强的酸性。其中[Bmim]Br-Fe₂Cl₆催化合成丁二酸二异丙酯效果良好,催化剂用量为丁二酸质量的10.0%,反应温度100℃,反应时间4 h,酸醇摩尔比为1：5,丁二酸二异丙酯收率为88.9%,酯化率达92.7%。离子液体重复使用6次后,产品收率下降1.7%。     

聚丁二酸丁二醇酯/乙烯-醋酸乙烯共混物的形态与性能研究

用乙烯-醋酸乙烯橡胶（EVM）对聚丁二酸丁二醇酯（PBS）进行增韧改性,通过添加过氧化二异丙苯（DCP）使得PBS与EVM的相容性增强。结果表明,随着DCP含量的增大,PBS/EVM共混物的拉伸强度、断裂伸长率、肖氏硬度等力学性能先升高,随后又降低,其中拉伸强度由7 MPa 提高到17 MPa,100 %定伸应力由2 MPa提高到10 MPa;加入DCP使得PBS的结晶由受限结晶变为正常结晶;DCP的适宜添加量为0.3份。     

亚精胺对小鼠骨骼肌自由基代谢影响及抗疲劳的效果研究

目的：研究亚精胺（spermidine,SPD）对骨骼肌自由基代谢的影响以及抗疲劳作用。方法：实验分为生理盐水组、SPD低剂量组（0.5 mmol/（kg·d））、中剂量组（1.0 mmol/（kg·d））、高剂量组（1.5 mmol/（kg·d））以及西洋参口服液阳性对照组（总皂苷30 mg/（kg·d））,每周灌胃6 d共30 d,每次灌胃前称量小鼠体质量调整灌胃溶液量,灌胃期间进行每天45 min无负重游泳训练。各组随机选取10 只小鼠测试力竭游泳时间;各组剩余10 只负重游泳30 min,休息30 min后取材,检测血清肌酸激酶（creatine kinase,CK）、骨骼肌谷胱甘肽-过氧化物酶（glutathione peroxidase,GSH-Px）、总超氧化物歧化酶（total-superoxide dismutase,T-SOD）、琥珀酸脱氢酶（succinate dehydrogenase,SDH）活性和骨骼肌丙二醛（malondialdehyde,MDA）含量。结果：与生理盐水组比较,SPD能显著延长小鼠力竭游泳时间（P＜0.05）;低、中剂量组骨骼肌中GSH-Px、T-SOD、SDH酶活性显著提高（P＜0.05）,MDA含量显著降低（P＜0.05）;SPD组与西洋参组比较,低、中剂量抗疲劳效果有非常显著性（P＜0.05）差异,高剂量抗疲劳效果略优（P＞0.05）。结论：0.5～1.0 mmol/（kg·d） SPD可以增加抗氧化酶的活性,减少自由基的积累,提高骨骼肌细胞膜代谢能力和抗损伤能力,显著推迟小鼠疲劳发生。     

阻燃聚丁二酸丁二醇酯复合材料的制备及其阻燃性能研究

采用熔融共混技术,将次磷酸铝(AHP)和三聚氰胺氰尿酸盐(MC)引入聚丁二酸丁二醇酯(PBS),制备了一系列阻燃PBS复合材料,并采用极限氧指数、垂直燃烧、微型量热测试以及热失重分析研究了复合材料的阻燃性能以及热稳定性。结果表明,AHP可以有效提高PBS复合材料的阻燃性能;AHP与MC复配可以进一步提高复合材料的阻燃性能,两者质量比为2∶1,添加量为20 %（质量分数,下同）即可使复合材料达到UL 94 V 0级别,极限氧指数达到29 %;AHP以及复合阻燃体系可以有效提高复合材料初始分解温度及其高温稳定性。