目的模拟脑组织弹性模量制备相应二维培养基,比较亚低温联合温敏脐带间充质干细胞(ts UC)与常温下脐带间充质干细胞(UC)的分化特性。方法应用单、双丙烯酰胺的聚合作用,制备弹性模量为0.5 k Pa的聚丙烯酰胺(PA)水凝胶,用于模拟脑组织的...目的模拟脑组织弹性模量制备相应二维培养基,比较亚低温联合温敏脐带间充质干细胞(ts UC)与常温下脐带间充质干细胞(UC)的分化特性。方法应用单、双丙烯酰胺的聚合作用,制备弹性模量为0.5 k Pa的聚丙烯酰胺(PA)水凝胶,用于模拟脑组织的生物力学环境,并测其弹性模量。从新生儿脐带中分离培养脐带间充质干细胞,通过感染携温度敏感型猿猴病毒40大T抗原(ts-SV40LT)基因的逆转录病毒来制备ts UC。实验分为3组:UC+常温+玻片组(A组)、UC+常温+0.5 k Pa组(B组)、ts UC+亚低温+0.5 k Pa组(C组)。动态观察各组细胞的生长情况和形态变化,并于7 d后行细胞免疫荧光检测各组细胞的分化水平并计算分化神经元的轴突长度。结果 PA水凝胶弹性模量的检测结果为(0.50±0.03)k Pa。B、C两组部分细胞出现细长的胞突,并存在β-tubulinⅢ阳性细胞,A组细胞镜下无明显神经元形态,也无β-tubulinⅢ阳性表达。B、C两组的神经元分化率以及荧光下轴突长度均明显高于A组,但组间差异无统计学意义(P>0.05)。结论在模拟脑组织弹性模量的环境中,ts UC具有向神经元分化的能力,可应用于亚低温治疗下脑损伤修复的细胞移植研究。展开更多
为进一步解析甘蓝型油菜温敏细胞核雄性不育系(GMS)TE5A的不育机理,筛选与育性蛋白Bna A.tsMs互作的重要蛋白。提取不育系TE5A的幼蕾(直径≤2mm)总RNA,利用SMART(switching mechanism at 5'end of the RNA transcript)技术构建酵母...为进一步解析甘蓝型油菜温敏细胞核雄性不育系(GMS)TE5A的不育机理,筛选与育性蛋白Bna A.tsMs互作的重要蛋白。提取不育系TE5A的幼蕾(直径≤2mm)总RNA,利用SMART(switching mechanism at 5'end of the RNA transcript)技术构建酵母双杂交cDNA文库和诱饵载体p GBKT7-Bna A.tsMs,转化酵母菌株Y2H gold,检测其毒性和自激活活性,通过Mating方法筛选与蛋白Bna A.tsMs互作的蛋白,并根据基因注释推测其功能。结果成功地构建了甘蓝型油菜温敏细胞核雄性不育系TE5A幼蕾酵母双杂交cDNA文库,文库库容量为2×107cfu,重组率达到100%,插入片段平均长度大于1.8kb。发现诱饵载体p GBKT7-Bna A.tsMs对酵母没有毒性,没有自激活活性。筛选出49个候选互作蛋白,其中有丝分裂纺锤体检测点蛋白(BUBR1)、周期蛋白D3(cyclin-D3)和F-box蛋白(FBW2)三个互作蛋白可能与该不育蛋白相互作用,共同调控该不育系TE5A的育性。展开更多
Sterility changeover induced by low temperature in male sterility line CMS7311 of heading Chinese cabbage ( Brassica campestris L. ssp. penkinsis) was investigated under constant temperature, day/night alternating tem...Sterility changeover induced by low temperature in male sterility line CMS7311 of heading Chinese cabbage ( Brassica campestris L. ssp. penkinsis) was investigated under constant temperature, day/night alternating temperature in light-growth-incubator and outdoor natural day/night alternating temperature respectively. It showed that the sterility of CMS7311 has significant change with temperature. The constant temperature of 6 - 12 degreesC was suitable to induce the changeover of sterility (CGS) of CMS7311 ; the shortest treatment time for CGS induction at this temperature was 3 d. The significant value of sterility changeover of CMS7311 occurred at the constant temperature of 6 - 9 degreesC after treatment for 6 - 9 d. The intensity of CGS was stronger under constant temperature than under alternate temperature, but the shortest treatment time inducing CGS has no difference between them. When treated for 9 d under the day/night alternating temperature of 11/7 degreesC, its sterility could also turn to normal fertility (near to sterile grade I or zero). In normal condition, the interval from the end of temperature treatment to the beginning of CGS induction was 10 - 16 d. In the condition of natural day/night alternating temperature, the lower limit of temperature for effective CGS induction was at the daily mean temperature ( DMT) of 3. 5 - 6. 8 degreesC, and the shortest treatment time which could induce the sterility changeover was also longer than that under constant temperature, being 11d at DMT of 1.5 - 3.1 degreesC. In addition, for the apical dominance, the flower bud on the first lateral branch showed the CGS 8 - 10 d later than the flower bud on the main stem under the same temperature with the same days of treatment. The intensity of CGS of CMS7311 on the first lateral branch was also weaker than the flower bud on the main stem.展开更多
The chemical structure of end groups influenced the phase transition temperature of thermoresponsive polymers. We demonstrated a strategy for the preparation of the pH/thermo-responsive polymeric nanoparticles via sub...The chemical structure of end groups influenced the phase transition temperature of thermoresponsive polymers. We demonstrated a strategy for the preparation of the pH/thermo-responsive polymeric nanoparticles via subtle modification of end groups of thermoresponsive polymer segments with a carboxyl group and revealed its potential application for enhanced intracellular drug delivery. By developing a polymeric nanoparticle composed of poly(aliphatic ester) as the inner core and thermoresponsive polyphosphoester as the outer shell, we showed that end groups of thermoresponsive polyphosphoester segments modified by carboxyl groups exhibited a pH/thermo-responsive behavior due to the hydrophilic to hydrophobic transitions of the end groups in response to the pH. Moreover, by encapsulating doxorubicin into the hydrophobic core of such pH/thermo-responsive polymer nanoparticles, their intracellular delivery and cytotoxicity to wild-type and drug-resistant tumor cells were significantly enhanced through the phase-transition-dependent drug release that was triggered by endosomal/lysosomal pH. This novel strategy and the multi-responsive polymer nanoparticles achieved by the subtle chain-terminal modification of thermoresponsive polymers provide a smart platform for biomedical applications.展开更多
文摘目的模拟脑组织弹性模量制备相应二维培养基,比较亚低温联合温敏脐带间充质干细胞(ts UC)与常温下脐带间充质干细胞(UC)的分化特性。方法应用单、双丙烯酰胺的聚合作用,制备弹性模量为0.5 k Pa的聚丙烯酰胺(PA)水凝胶,用于模拟脑组织的生物力学环境,并测其弹性模量。从新生儿脐带中分离培养脐带间充质干细胞,通过感染携温度敏感型猿猴病毒40大T抗原(ts-SV40LT)基因的逆转录病毒来制备ts UC。实验分为3组:UC+常温+玻片组(A组)、UC+常温+0.5 k Pa组(B组)、ts UC+亚低温+0.5 k Pa组(C组)。动态观察各组细胞的生长情况和形态变化,并于7 d后行细胞免疫荧光检测各组细胞的分化水平并计算分化神经元的轴突长度。结果 PA水凝胶弹性模量的检测结果为(0.50±0.03)k Pa。B、C两组部分细胞出现细长的胞突,并存在β-tubulinⅢ阳性细胞,A组细胞镜下无明显神经元形态,也无β-tubulinⅢ阳性表达。B、C两组的神经元分化率以及荧光下轴突长度均明显高于A组,但组间差异无统计学意义(P>0.05)。结论在模拟脑组织弹性模量的环境中,ts UC具有向神经元分化的能力,可应用于亚低温治疗下脑损伤修复的细胞移植研究。
文摘为进一步解析甘蓝型油菜温敏细胞核雄性不育系(GMS)TE5A的不育机理,筛选与育性蛋白Bna A.tsMs互作的重要蛋白。提取不育系TE5A的幼蕾(直径≤2mm)总RNA,利用SMART(switching mechanism at 5'end of the RNA transcript)技术构建酵母双杂交cDNA文库和诱饵载体p GBKT7-Bna A.tsMs,转化酵母菌株Y2H gold,检测其毒性和自激活活性,通过Mating方法筛选与蛋白Bna A.tsMs互作的蛋白,并根据基因注释推测其功能。结果成功地构建了甘蓝型油菜温敏细胞核雄性不育系TE5A幼蕾酵母双杂交cDNA文库,文库库容量为2×107cfu,重组率达到100%,插入片段平均长度大于1.8kb。发现诱饵载体p GBKT7-Bna A.tsMs对酵母没有毒性,没有自激活活性。筛选出49个候选互作蛋白,其中有丝分裂纺锤体检测点蛋白(BUBR1)、周期蛋白D3(cyclin-D3)和F-box蛋白(FBW2)三个互作蛋白可能与该不育蛋白相互作用,共同调控该不育系TE5A的育性。
文摘Sterility changeover induced by low temperature in male sterility line CMS7311 of heading Chinese cabbage ( Brassica campestris L. ssp. penkinsis) was investigated under constant temperature, day/night alternating temperature in light-growth-incubator and outdoor natural day/night alternating temperature respectively. It showed that the sterility of CMS7311 has significant change with temperature. The constant temperature of 6 - 12 degreesC was suitable to induce the changeover of sterility (CGS) of CMS7311 ; the shortest treatment time for CGS induction at this temperature was 3 d. The significant value of sterility changeover of CMS7311 occurred at the constant temperature of 6 - 9 degreesC after treatment for 6 - 9 d. The intensity of CGS was stronger under constant temperature than under alternate temperature, but the shortest treatment time inducing CGS has no difference between them. When treated for 9 d under the day/night alternating temperature of 11/7 degreesC, its sterility could also turn to normal fertility (near to sterile grade I or zero). In normal condition, the interval from the end of temperature treatment to the beginning of CGS induction was 10 - 16 d. In the condition of natural day/night alternating temperature, the lower limit of temperature for effective CGS induction was at the daily mean temperature ( DMT) of 3. 5 - 6. 8 degreesC, and the shortest treatment time which could induce the sterility changeover was also longer than that under constant temperature, being 11d at DMT of 1.5 - 3.1 degreesC. In addition, for the apical dominance, the flower bud on the first lateral branch showed the CGS 8 - 10 d later than the flower bud on the main stem under the same temperature with the same days of treatment. The intensity of CGS of CMS7311 on the first lateral branch was also weaker than the flower bud on the main stem.
基金supported by the Ministry of Science and Technology of China(2010CB934001)the National Natural Science Foundation of China(51125012,51203145)
文摘The chemical structure of end groups influenced the phase transition temperature of thermoresponsive polymers. We demonstrated a strategy for the preparation of the pH/thermo-responsive polymeric nanoparticles via subtle modification of end groups of thermoresponsive polymer segments with a carboxyl group and revealed its potential application for enhanced intracellular drug delivery. By developing a polymeric nanoparticle composed of poly(aliphatic ester) as the inner core and thermoresponsive polyphosphoester as the outer shell, we showed that end groups of thermoresponsive polyphosphoester segments modified by carboxyl groups exhibited a pH/thermo-responsive behavior due to the hydrophilic to hydrophobic transitions of the end groups in response to the pH. Moreover, by encapsulating doxorubicin into the hydrophobic core of such pH/thermo-responsive polymer nanoparticles, their intracellular delivery and cytotoxicity to wild-type and drug-resistant tumor cells were significantly enhanced through the phase-transition-dependent drug release that was triggered by endosomal/lysosomal pH. This novel strategy and the multi-responsive polymer nanoparticles achieved by the subtle chain-terminal modification of thermoresponsive polymers provide a smart platform for biomedical applications.
