Effect of AMPKα2 gene silencing by shRNA recombinant plasmid on chloride-mediated anoxia/reoxygenation injury in rat cardiomyocytes

AIM: To explore the role of AMP-activated protein kinase α2 subunit (AMPKα2) gene in chloride-mediated anoxia/reoxygenation (A/R) injury by transfection of short-hairpin RNA (shRNA) expression vector targeting to AMPKα2 gene into H9c2 cardiomyocytes. METHODS: Recombinant shRNA expression vector pSuper-AMPKα2 targeting to AMPKα2 gene was constructed and transfected into H9c2 cardiomyocytes. The protein expression of AMPKα2 was determined by Western blotting. The cells were divided into 5 groups: control group, A/R group, Cl^--free A/R group, pSuper+Cl^--free A/R group and pSuper-AMPKα2 shRNA+Cl^--free A/R group. After treatment, the cell viability was detected by MTT assay. LDH activity was analyzed with an automatic biochemical analyzer. The apoptotic rate and the level of intracellular ROS was measured by flow cytometry. The activity of SOD and GSH-Px was analyzed by a colorimetric method. RESULTS: The result of sequencing proved that the recombinant plasmid pSuper-AMPKα2 shRNA was correctly constructed. The protein level of AMPKα2 significantly decreased after the plasmid was transfected into the cardiomyocytes. Compared with A/R group, the cell viability and the activity of SOD and GSH-Px were significantly increased, while the activity of LDH, apoptotic rate and ROS production were significantly decreased in Cl^--free A/R group. The protective effect of Cl^--free solution on the A/R-induced injury of cardiomyocytes was abolished, and the ROS production was increased and the activity of SOD and GSH-Px was decreased after the cells were transfected with pSuper-AMPKα2 shRNA. CONCLUSION: Recombinant plasmid pSuper-AMPKα2 shRNA is successfully constructed, and silencing of AMPKα2 gene abolishes the protective effect of Cl^--free solution on A/R injury.     

肉鸡胫骨软骨症发病趋势及组织学研究

本试验采用４８０只１日龄Ａｒｂｒｏ Ａｃｒｅｓ商品代仔公鸡，研究胫骨软骨症的发生特征，胫骨软骨症随肉鸡生长的动态发展趋势以及与日粮氯和镁水平之间的关系。试验为２×２×４因子设计，日粮氯，镁分别采用２个水平，氯为０．１１５％和０．３５％，镁为０．１５％和０．４０％。时间因素为第三个因子，１０天为一个阶段，共４个阶段。试验期为４０天，实验结果表明，肉鸡胫骨软骨症的发生与发展具有明显的时间性并与肉鸡的生     

氯化钙对始花期辣椒抗冷性的影响

用不同浓度的氯化钙溶液对始花期辣椒进行处理,研究了氯化钙对缓解始花期辣椒低温胁迫的影响。研究结果表明,低温环境下,氯化钙降低了辣椒叶片中的电解质渗透率和MDA含量,增加了POD、SOD活性和Pro含量,在一定程度上缓解了低温伤害,其中20mmol/L氯化钙的作用效果最好。     

CaCl2对冬小麦抗旱性影响的研究

[目的]研究氯化钙和冬小麦抗旱性的关系。[方法]用不同浓度氯化钙溶液喷施小麦苗期叶片,测定叶中脯氨酸、丙二醛、可溶性糖含量及SOD活性;用不同浓度氯化钙溶液拌种后测定小麦种子萌发率;用不同浓度氯化钙溶液浸种后测定幼苗复活能力。[结果]结果表明,用浓度为100mmol／L的氯化钙溶液喷施小麦苗期叶片,能显著增加小麦幼苗的脯氨酸和可溶性糖含量,丙二醛浓度降低,SOD活性升高、并保持水力;用100mmol／L氯化钙浸种,可提高小麦种子在干旱条件下的萌发率。[结论]氯化钙可作为小麦苗期抗旱的一种有效的植物生长调节剂。     

Elimination of chloride interference in the phenoldisulphonic acid method of nitrate determination in soils

Abstract

A technique was developed to eliminate chloride interference using antimony (III) in the determination of nitrates in soils by phenoldisulphonic acid method. This method was found effective upto nearly 300 ppm Cl^‐ in soils ranging in pH from 5.6 to 8.3. By avoiding repeated filtrations of chloride precipitates, this method allowas quick analysis of soils for nitrates in single soil extracts containing other mineral nitrogen fractions.     

Effectiveness of Chloride Compared to 3,4-Dimethylpyrazole Phosphate on Nitrification Inhibition in Soil

Microbial oxidation of ammonium to nitrate may impose dangers to ecosystem functioning through soil and atmosphere contamination with end products or intermediate gases. A wide range of chemicals can inhibit nitrification under soil and laboratory conditions. In the present study, the effectiveness of chloride compared to 3,4-dimethylpyrazole phosphate (DMPP) as a standard nitrification inhibitor was evaluated. The results showed that DMPP (especially with double concentrations) inhibited nitrification for a longer time, until the end of incubation period. Chloride in the form of ammonium chloride (NH₄Cl) or potassium chloride (KCl) also significantly inhibited nitrification compared to the control during the 7-week incubation period. This inhibition was positively correlated with applied chloride concentrations in soil. During a 5-week incubation period, the strongest concentration (500 mg/kg soil) showed more inhibition than concentrations of 250 or 100 mg/kg soil, particularly when compared to control. The results suggest that beside commercial nitrification inhibitors, chloride can significantly inhibit microbial nitrification in soil. Therefore, when chloride is not a soil problem, the chloride form of nitrogen fertilizers (e.g., ammonium chloride) could be a proper nitrogen fertilizer.     

施氯量对丽江烤烟烟叶生长·产量和化学成分的影响

[目的]为寻找丽江金沙江河谷地区烟田适宜施氯量。[方法]试验设置6个施氯量处理(KCl 0、30、45、90、135、180 kg/hm2),比较各处理的烤烟生长、产质量表现。[结果]随施氯量增加,烟株的团棵期、现蕾期分别提前了2～3、3～5 d,终采期及大田期均延长了1～7d,烟株株高增加3.55～7.78 cm。增施氯使产量、产值、均价、上等烟比例、中上等烟比例分别提高了0.59%～10.70%、3.75%～10.92%、4.05%～8.56%、6.25%～28.13%、2.35%～5.88%。当施氯量为KCl 180 kg/hm2时虽产量最大,但较对照均价已下降0.82元/kg。施氯较为一致地提高了各部位烟叶的含氮量、含氯量,均降低了烟叶烟碱含量。施氯量效应表现为上部>中部>下部。施氯提高了上部烟叶的总糖含量,而降低了中部、下部烟叶的总糖含量。[结论]从烟叶的可用性和经济效益综合考虑,以KCl 135 kg/hm2为丽江砂质冲积型水稻土最佳施氯量。     

土壤──植物系统中的氯及施用含氯肥料的几个问题

分析了土壤中Ｃｌ的来源与分布；植物对Ｃｌ的生理需求与忍耐；施用含Ｃｌ肥料对土壤、植物的影响；并提出了施用含Ｃｌ肥料应注意的几个问题．     

离子色谱法和毛细管电泳法测定土壤中氯离子、 硫酸根及其差异性

分别采用离子色谱法(IC)、毛细管电泳法(CE)两种仪器方法对不同pH土壤中Cl~–、SO_4~(2–)含量进行测定,并对其结果进行差异性分析。结果显示:参照标准物质的参考值(滴定法),IC与CE测定值的准确度、回收率均满足实验分析要求,但精密度差异较大,IC(RSD,3.61%)的稳定性优于CE(RSD,8.97%)。据差异性(F与t检验)分析,两种仪器方法测定酸性土壤中Cl~–、SO_4~(2–)含量存在显著性差异,而碱性、中性土壤的测定结果保持一致。对比4个被测样品基本性质发现,酸性土壤的pH与离子强度均低于其他样品,从而影响了石英毛细管的电渗流,最终改变了CE分离过程,这可能是Cl~–结果偏离的主要因素。同时,对于IC,酸性土壤较中性、碱性土壤更易由于离子交换效应产生次级保留(拖尾)。此外,采用碱性分离体系分离酸性样品易形成结晶,从而导致SO_4~(2–)含量的偏离。可见,两种方法各有优缺点。但是,IC较经典,而CE是一种新兴的仪器方法。测定像土壤这样基体较复杂的样品(特别是酸性土壤)中阴离子的仪器条件还需要进行更多摸索与优化,以促进这两种方法在土壤领域的推广与应用。