Hyperbaric oxygen therapy activates CREB/BDNF signaling pathway to reduce synaptic damage in hippocampal neurons of Alzheimer disease mice

AIM To investigate the effect of hyperbaric oxygen (HBO) on synaptic damage of hippocampal neurons in APP/PS1 transgenic (TG) mice and its possible mechanism. METHODS The 6-month-old male APP/PS1 TG mice were randomly divided into TG group, HBO group and cAMP response element binding protein (CREB) inhibitor H89 group, with 10 mice in each group. Ten male wild-type (WT) C57BL/6 mice of the same age were used as negative control group (WT group). The mice in HBO and H89 groups were treated with HBO for 6 cycles, while the mice in WT group and TG group were not treated. The learning and memory abilities were observed by Morris water maze. The nesting ability of the mice was detected by nesting test. The Nissl bodies in hippocampal neurons were observed by Nissl staining. The mRNA expression of CREB and brain-derived neurotrophic factor (BDNF) in hippocampus was detected by real-time PCR. The protein levels of synapsin (SYN), postsynaptic density protein 95 (PSD95), growth-associated protein 43 (GAP43), CREB, phosphorylated CREB (p-CREB) and BDNF in the hippocampus were determined by Western blot. RESULTS Compared with WT group, the learning and memory abilities of the mice in TG group were signilficantly reduced (P<0.05). In addition, the nesting score, the number of Nissl bodies in the hippocampal neurons, the mRNA expression of CREB and BDNF, and the protein levels of SYN, PSD95, GAP43, p-CREB and BDNF were also decreased significantly (P<0.05). Compared with TG group, the learning and memory abilities of the mice in HBO group were improved (P<0.05). Meanwhile, the nesting scores of the mice were significantly increased (P<0.05), the neurons in the hippocampus were arranged neatly, and the number of Nissl bodies, the relative mRNA expression of CREB and BDNF,and the protein levels of SYN, PSD95, GAP43, p-CREB and BDNF were also increased significantly (P<0.05). Compared with HBO group, the mice in H89 group had poor learning and memory abilities, lowered nesting scores and decreased number of Nissl bodies. Futhermore, the relative mRNA expression of CREB and BDNF, and the protein levels of SYN, PSD95, GAP43, p-CREB and BDNF were also decreased significantly (P<0.05). CONCLUSION HBO improves the learning and memory abilities of APP/PS1 TG mice, and its mechanism may be related to activating the CREB/BDNF signaling pathway to reduce synaptic damage of hippocampal neurons in mice.     

水杨酸与高温锻炼对高温胁迫下葡萄叶肉细胞质膜ATPase活性的影响

采用水性两相分配法对经水杨酸(SA)和高温锻炼处理过的葡萄幼苗叶肉细胞中ATPase进行了分离和测定.结果表明:高温下,细胞质膜ATPase活性随着胁迫程度的加深均呈下降趋势,经SA和高温锻炼预处理后再经高温胁迫,发现质膜ATPase的活性低于正常条件下的水平(CK1),但明显高于未经处理直接进行高温胁迫后ATPase活性水平,即高温锻炼和SA预处理的质膜酶活仍保持了较高的活性,并且后一种处理效果更明显.说明质膜上ATPase活性的变化对高温胁迫作出了一定的响应,SA和高温锻炼对提高葡萄幼苗叶片的抗热性与二者可以维持细胞质膜上ATPase活性的稳定有关.     

Density separation of soil organic matter across three land uses in calcareous soils of Iran

ABSTRACT

The aim of this study was to examine the usefulness of physical and chemical fractionation in quantifying soil organic matter (SOM) in different stabilized fraction pools. Soil samples from three land use types in Lorestan province, Southwest Iran were examined to account for the amount of organic carbon and nitrogen in different SOM fractions. Size/density separation and chemical oxidation methods were applied to separate the SOM fractions including particulate organic matter (POM), Si + C (silt and clay), DOC (dissolved organic C), rSOM (oxidation-resistant organic carbon and nitrogen) and S + SA (sand and stable aggregates). The values obtained for TOC, TN, and HWC were highest in forest lands followed by the range and agricultural lands. Among the SOM fractions, S + SA showed the highest values (5.75, 5.77 and 20.6 g kg^?1 for agriculture, range and forest lands respectively) followed by POM, Si + C, rSOM, and DOC. The concentrations of C and N in the labile fractions obtained the higher values than in the stabilized fractions. Forest lands had the highest amounts of organic C and N among all fractions whereas agricultural lands showed highest values for inorganic C content of soils in different fractions.     

菜心对邻苯二甲酸酯(PAEs)吸收途径的初步研究

采用玻璃室处理和污染土壤覆盖原土壤来控制PAEs来源进行盆栽试验，应用GC/MS联机检测技术初步研究了菜心对PAEs的吸收途径。结果表明：污染土壤处理与污染土壤上覆盖原土壤处理相比，前者菜心茎叶中DBP和DEHP的含量均高于后者，但相差不大，表明菜心茎叶可以吸收污染土壤中挥发出来的DBP和DEHP，而根系吸收运移是菜心茎叶中DBP和DEHP的主要来源途径。玻璃室处理增加了菜心茎叶和根系中DBP的含量，而对DEHP的影响趋势不明显。DBP与DEHP相比，前者更易被菜心根系吸收并向地上部(茎叶)运移，后者主要滞留在根部。     

Notch1 promotes renal tubulointerstitial fibrosis in renal tissues of diabetic mice by inhibiting autophagy through Akt/mTOR signaling pathway

AIM: To observe the changes of Notch1 expression and autophagy in the renal tissues of diabetic mice, and to explore the regulatory effect of Notch1 on tubulointerstitial fibrosis by inhibiting autophagy in diabetic nephro-pathy. METHODS: The mice were randomly divided into normal control group (db/m mice) and diabetes group (db/db mice), with 8 rats in each group. After 12 weeks of feeding, the mice were sacrificed and the corresponding biochemical indexes were measured. The protein expression of Notch1 in the renal tubular epithelial cells was observed by immunohistochemical staining. The protein levels of Notch1, PTEN, p-Akt (Thr308), Akt, p-mTOR (Ser2448), mTOR, LC3, P62, collagen type Ⅰ (Col-Ⅰ) and collagen type Ⅲ (Col-Ⅲ) were determined by Western blot. RESULTS: Compared with the db/m mice, the blood glucose, glycosylated hemoglobin, serum creatinine, triglyceride and total cholesterol were increased in the db/db mice (P<0.01). Renal tubular epithelial cell vacuolar degeneration, renal tubular expansion and interstitial inflammatory cell infiltration in db/db mouse renal tissues with HE staining were observed. The images of Masson staining showed collagenous fiber-like substance deposition in the glomerular capillaries and renal interstitium, and disarrangement of tubular structure in the renal tissues of db/db mice. The protein expression levels of PTEN and LC3-Ⅱ were decreased (P<0.01 or P<0.05), while the protein levels of Notch1, P62, p-mTOR (Ser2448), p-Akt (Thr308), Col-I and Col-III were increased in the db/db mice as compared with the db/m mice (P<0.01). However, no significant change of total mTOR and Akt proteins between the 2 groups was found. CONCLUSION: Notch1 protein expression was increased, PTEN expression was significantly reduced, Akt/mTOR pathway was activated, autophagy was inhibited, and fibrosis was aggravated in the renal tissues of the diabetic mice.     

MC1R c.676A>G与山羊皮肤色素沉积的关系及其对黑色素合成的影响

为探讨山羊MC1R基因c.676A>G突变与山羊皮肤色素沉积的关系,及其对黑色素合成和cAMP信号通路下游色素相关基因表达的影响：一方面采用直接测序法检测酉州乌羊及其杂交后代群体(120个个体)MC1R基因c.676A>G的突变情况,用色差仪测量不同基因型个体的腹部皮肤色度值,分析c.676A>G突变与皮肤色素沉积的关系;另一方面,构建野生型(MC1R c.676A)和突变型(MC1R c.676G)真核表达载体,采用脂质体介导法转染到小鼠皮肤黑色素瘤细胞(B16-F10)中进行过表达,利用酶标仪检测各组细胞黑色素含量的差异,并通过实时荧光定量PCR方法检测各组细胞中cAMP信号通路下游色素相关基因(MITF、TYR、TYRP1、DCT)的表达差异性。结果显示：酉州乌羊及其杂交后代群体中,c.676A>G位点均以GG基因型占优势,不同基因型群体的皮肤色度值差异不显著(P>0.05)。MC1R突变组(MC1R c.676G)细胞中的黑色素含量极显著(P<0.05)高于MC1R野生组(MC1R c.676A)。MITF、TYRP1和DCT基因在MC1R突...     

花粉管通道法在玉米自交系改良中的应用

就几年来花粉管通道法在玉米自交系改良中的应用情况加以概括,提出了导入方法的适宜细则,对后代变异情况加以论述,并对今后该项工作的开展提出几点建议.